Anti-cd3 antibodies, anti-cd123 antibodies and bispecific antibodies specifically binding to cd3 and/or cd123

Abstract

The present invention concerns antibody-like binding protein specifically binding to CD3 and binding specifically to at least one further antigen, for example CD123. The present invention also concerns antibody-like binding protein specifically binding to CD123 and binding specifically to at least one further antigen. The invention further concerns anti-CD3 antibodies and anti-CD123 antibodies. The invention also relates to pharmaceutical compositions comprising the antibody-like binding protein, anti-CD3 antibodies or anti-CD123 antibodies of the invention, and their use to treat cancer. The invention further relates to isolated nucleic acids, vectors and host cells comprising a sequence encoding said antibody-like binding protein, anti-CD3 or anti-CD123 antibody and the use of said anti-CD123 antibody as a diagnostic tool.

1 : An isolated antibody that binds to the extracellular domain of human CD3ε protein comprising:
 a) a heavy chain variable domain comprising a CDR1-H consisting of an amino acid sequence GFX 1 X 2 X 3 X 4 AW (SEQ ID NO: 331) wherein X 1  is T or S, X 2  is F or V, X 3  is S or T and X 4  is N, K, L or Y, or any combination thereof, and a CDR2-H consisting of an amino acid sequence IKX 1 X 2 X 3 NX 4 YX 5 T (SEQ ID NO: 332) wherein X 1  is A or D, X 2  is K or R, X 3  is S or A, X 4  is N or S, and X 5  is A or E, or any combination thereof; and a CDR3-H consisting of an amino acid sequence TWRHYYSSHTMDA (SEQ ID NO: 69), or RALTYYGYKRDAMDG (SEQ ID NO: 129), or RX 1 X 2 X 3 YX 4 X 5 X 6 X 7 X 8 X 9 X 10 X 11 DX 12  (SEQ ID NO: 333) wherein X 1  is Y, G or A, X 2  is V, T or L, X 3  is H, N, Y or Q, X 4  is G, R or A, X 5  is F or V or no amino acid, X 6  is R or no amino acid, X 7  is F, S or I or no amino acid, X 8  is F, L, N, M, Y, S, A or G, X 9  is Y, A, K, S, N, T, F or L, X 10  is A, P, G or T, X 11  is M, L, F or S, and X 12  is A, V or Y, or any combination thereof; and 
 a light chain variable domain comprising a CDR1-L consisting of an amino acid sequence QX 1 LX 2 HX 3 NGX 4 TY (SEQ ID NO: 334) wherein X 1  is R or S, X 2  is V or E, X 3  is N, D or T, and X 4  is N or Y, or any combination thereof; and a CDR2-L consisting of an amino acid sequence KVS; and a CDR3-L consisting of an amino acid sequence GQGX 1 X 2 YPFT (SEQ ID NO: 335) wherein X 1  is T, A or S and X 2  is H, E or Q, or any combination thereof; or 
 b) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 30 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 30 by one amino acid substitution; and a CDR2-H of amino acid sequence SEQ ID NO: 31 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 31 by one or more amino acid substitutions; and a CDR3-H of amino acid sequence SEQ ID NO: 32 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 32 by one amino acid substitution; and 
 a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 34 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 34 by one amino acid substitution; and a CDR2-L of amino acid sequence RDD or an amino acid sequence differing from the amino acid sequence RDD by one amino acid substitution; and a CDR3-L of amino acid sequence SEQ ID NO: 35 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 35 by one amino acid substitution; or 
 c) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 50 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 50 by one amino acid substitution; and a CDR2-H of amino acid sequence SEQ ID NO: 51 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 51 by one or more amino acid substitutions; and a CDR3-H of amino acid sequence SEQ ID NO: 52 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 52 by one amino acid substitution; and 
 a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 54 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 54 by one amino acid substitution; and a CDR2-L of amino acid sequence NAN or an amino acid sequence differing from the amino acid sequence NAN by one amino acid substitution; and a CDR3-L of amino acid sequence SEQ ID NO: 55 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 55 by one amino acid substitution; or 
 d) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 90 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 90 by one amino acid substitution; and a CDR2-H of amino acid sequence SEQ ID NO: 91 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 91 by one or more amino acid substitutions; and a CDR3-H of amino acid sequence SEQ ID NO: 32 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 32 by one amino acid substitution; and 
 a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 93 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 93 by one amino acid substitution; and a CDR2-L of amino acid sequence GAS or an amino acid sequence differing from the amino acid sequence GAS by one amino acid substitution; and a CDR3-L of amino acid sequence SEQ ID NO: 94 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 94 by one amino acid substitution; or 
 e) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 96 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 96 by one amino acid substitution; and a CDR2-H of amino acid sequence SEQ ID NO: 97 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 97 by one or more amino acid substitutions; and a CDR3-H of amino acid sequence SEQ ID NO: 98 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 98 by one amino acid substitution; and 
 a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 100 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 100 by one amino acid substitution; and a CDR2-L of amino acid sequence NTN or an amino acid sequence differing from the amino acid sequence NTN by one amino acid substitution; and a CDR3-L of amino acid sequence SEQ ID NO: 101 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 101 by one amino acid substitution; or 
 f) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 103 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 103 by one amino acid substitution; and a CDR2-H of amino acid sequence SEQ ID NO: 104 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 104 by one or more amino acid substitutions; and a CDR3-H of amino acid sequence SEQ ID NO: 105 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 105 by one amino acid substitution; and 
 a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 10 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 10 by one amino acid substitution; and a CDR2-L of amino acid sequence KVS or an amino acid sequence differing from the amino acid sequence KVS by one amino acid substitution; and a CDR3-L of amino acid sequence SEQ ID NO: 11 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 11 by one amino acid substitution; or 
 g) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 116 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 116 by one amino acid substitution; and a CDR2-H of amino acid sequence SEQ ID NO: 117 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 117 by one or more amino acid substitutions; and a CDR3-H of amino acid sequence SEQ ID NO: 118 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 118 by one amino acid substitution; and 
 a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 100 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 100 by one amino acid substitution; and a CDR2-L of amino acid sequence VTN or an amino acid sequence differing from the amino acid sequence VTN by one amino acid substitution; and a CDR3-L of amino acid sequence SEQ ID NO: 120 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 120 by one amino acid substitution; or 
 h) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 122 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 122 by one amino acid substitution; and a CDR2-H of amino acid sequence SEQ ID NO: 123 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 123 by one or more amino acid substitutions; and a CDR3-H of amino acid sequence SEQ ID NO: 124 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 124 by one amino acid substitution; and 
 a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 126 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 126 by one amino acid substitution; and a CDR2-L of amino acid sequence RDD or an amino acid sequence differing from the amino acid sequence RDD by one amino acid substitution; and a CDR3-L of amino acid sequence SEQ ID NO: 127 or an amino acid sequence differing from the amino acid sequence SEQ ID NO: 127 by one amino acid substitution. 
 
     
     
         2 : The isolated antibody according to  claim 1 , comprising:
 a) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 6, a CDR2-H of amino acid sequence SEQ ID NO: 7, and a CDR3-H of amino acid sequence SEQ ID NO: 8; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 10 or SEQ ID NO: 142, a CDR2-L of amino acid sequence KVS and a CDR3-L of amino acid sequence SEQ ID NO: 11; or   b) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 13, a CDR2-H of amino acid sequence SEQ ID NO: 14, and a CDR3-H of amino acid sequence SEQ ID NO: 15; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 17 or SEQ ID NO: 184, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 11; or   c) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 13, a CDR2-H of amino acid sequence SEQ ID NO: 19, and a CDR3-H of amino acid sequence SEQ ID NO: 20; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 22, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 11; or   d) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 24, a CDR2-H of amino acid sequence SEQ ID NO: 19, and a CDR3-H of amino acid sequence SEQ ID NO: 25; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 27, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 28; or   e) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 30, a CDR2-H of amino acid sequence SEQ ID NO: 31, and a CDR3-H of amino acid sequence SEQ ID NO: 32; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 34, a CDR2-L of amino acid sequence ROD, and a CDR3-L of amino acid sequence SEQ ID NO: 35; or   f) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 13, a CDR2-H of amino acid sequence SEQ ID NO: 37, and a CDR3-H of amino acid sequence SEQ ID NO: 38; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 10, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 28; or   g) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 13, a CDR2-H of amino acid sequence SEQ ID NO: 37, and a CDR3-H of amino acid sequence SEQ ID NO: 41; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 17, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 11; or   h) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 13, a CDR2-H of amino acid sequence SEQ ID NO: 37, and a CDR3-H of amino acid sequence SEQ ID NO: 44; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 10, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 11; or   i) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 13, a CDR2-H of amino acid sequence SEQ ID NO: 37, and a CDR3-H of amino acid sequence SEQ ID NO: 47; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 10, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 11; or   j) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 50, a CDR2-H of amino acid sequence SEQ ID NO: 51, and a CDR3-H of amino acid sequence SEQ ID NO: 52; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 54, CDR2-L of amino acid sequence NAN, and a CDR3-L of amino acid sequence SEQ ID NO: 55; or   k) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 57, a CDR2-H of amino acid sequence SEQ ID NO: 37, and a CDR3-H of amino acid sequence SEQ ID NO: 58; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 10, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 28; or   l) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 13, a CDR2-H of amino acid sequence SEQ ID NO: 37, and a CDR3-H of amino acid sequence SEQ ID NO: 61; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 10, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 11; or   m) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 64, a CDR2-H of amino acid sequence SEQ ID NO: 65, and a CDR3-H of amino acid sequence SEQ ID NO: 47; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 67, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 28; or   n) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 13, a CDR2-H of amino acid sequence SEQ ID NO: 37, and a CDR3-H of amino acid sequence SEQ ID NO: 69; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 10, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 71; or   o) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 13, a CDR2-H of amino acid sequence SEQ ID NO: 37, and a CDR3-H of amino acid sequence SEQ ID NO: 84; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 17, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 11; or   p) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 75, a CDR2-H of amino acid sequence SEQ ID NO: 76, and a CDR3-H of amino acid sequence SEQ ID NO: 77; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 10, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 11; or   q) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 80, a CDR2-H of amino acid sequence SEQ ID NO: 76, and a CDR3-H of amino acid sequence SEQ ID NO: 81; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 10, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 11; or   r) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 13, a CDR2-H of amino acid sequence SEQ ID NO: 37, and a CDR3-H of amino acid sequence SEQ ID NO: 84; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 10, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 11; or   s) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 13, a CDR2-H of amino acid sequence SEQ ID NO: 37, and a CDR3-H of amino acid sequence SEQ ID NO: 47; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 10, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 88; or   t) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 90, a CDR2-H of amino acid sequence SEQ ID NO: 91, and a CDR3-H of amino acid sequence SEQ ID NO: 32; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 93, a CDR2-L of amino acid sequence GAS, and a CDR3-L of amino acid sequence SEQ ID NO: 94; or   u) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 96, a CDR2-H of amino acid sequence SEQ ID NO: 97, and a CDR3-H of amino acid sequence SEQ ID NO: 98; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 100, a CDR2-L of amino acid sequence NTN, and a CDR3-L of amino acid sequence SEQ ID NO: 101; or   v) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 103, a CDR2-H of amino acid sequence SEQ ID NO: 104, and a CDR3-H of amino acid sequence SEQ ID NO: 105; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 10, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 11; or   w) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 80, a CDR2-H of amino acid sequence SEQ ID NO: 19, and a CDR3-H of amino acid sequence SEQ ID NO: 108; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 10, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 11; or   x) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 13, a CDR2-H of amino acid sequence SEQ ID NO: 37, and a CDR3-H of amino acid sequence SEQ ID NO: 1111 and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 113, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 114; or   y) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 116, a CDR2-H of amino acid sequence SEQ ID NO: 117, and a CDR3-H of amino acid sequence SEQ ID NO: 118; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 100, a CDR2-L of amino acid sequence VTN, and a CDR3-L of amino acid sequence SEQ ID NO: 120; or   z) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 122, a CDR2-H of amino acid sequence SEQ ID NO: 123, and a CDR3-H of amino acid sequence SEQ ID NO: 124; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 126, a CDR2-L of amino acid sequence ROD, and a CDR3-L of amino acid sequence SEQ ID NO: 127; or   aa) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 13, a CDR2-H of amino acid sequence SEQ ID NO: 19, and a CDR3-H of amino acid sequence SEQ ID NO: 129; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 10, a CDR2-L of amino acid sequence KVS, and a CDR3-L of amino acid sequence SEQ ID NO: 11; or   bb) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 103, a CDR2-H of amino acid sequence SEQ ID NO: 104, and a CDR3-H of amino acid sequence SEQ ID NO: 105; and a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 133, a CDR2-L of amino acid sequence LVS, and a CDR3-L of amino acid sequence SEQ ID NO: 134.   
     
     
         3 : An antibody-like binding protein that binds specifically to human CD3ε comprising two polypeptide chains that form two antigen-binding sites, wherein a first polypeptide has a structure represented by the formula [I]:
   V D1 -L 1 -V D2 -L 2 -C L   [I]
 
 and a second polypeptide has a structure represented by the formula [II]:
   V D3 -L 3 -V D4 -L 4 -C H1   [II]
 
 
 wherein:
 V D1  is a heavy or light chain variable domain of a first immunoglobulin; 
 V D2  is a heavy or light chain variable domain of a second immunoglobulin; 
 V D3  is a heavy or light chain variable domain of said second immunoglobulin; 
 V D4  is a heavy or light chain variable domain of said first immunoglobulin; 
 C L  is a light chain constant domain of an immunoglobulin; 
 C H1  is a C H1  heavy chain constant domain of an immunoglobulin; 
 L 1 , L 2 , L 3 , and L 4  are amino acid linkers; 
 
 wherein the first polypeptide and the second polypeptide form a cross-over light chain-heavy chain pair; and 
 wherein V D1  and V D4 , or V D2  and V D3  comprise a heavy chain variable domain and a light chain variable domain of an antibody according to  claim 1 . 
 
     
     
         4 : The antibody-like binding protein according to  claim 3 , wherein the polypeptide of formula [II] further comprises a Fc domain. 
     
     
         5 : The antibody-like binding protein according to  claim 4 , comprising two polypeptide chains that form two antigen-binding sites, wherein one polypeptide chain has a structure represented by the formula [I]:
   V D1 -L 1 -V D2 -L 2 -C L   [I]
   and a second polypeptide has a structure represented by the formula [III]:
   V D3 -L 3 -V D4 -L 4 -C H1 -Fc  [III]
 
   wherein:
 V D1  is a heavy or light chain variable domain of a first immunoglobulin; 
 V D2  is a heavy or light chain variable domain of a second immunoglobulin; 
 V D3  is a heavy or light chain variable domain of said second immunoglobulin; 
 V D4  is a heavy or light chain variable domain of said first immunoglobulin; 
 C L  is a light chain constant domain of an immunoglobulin; 
 C H1  is a C H1  heavy chain constant domain of an immunoglobulin; 
 Fc is the immunoglobulin hinge region and CH 2 , CH 3  immunoglobulin heavy chain constant domains of an immunoglobulin; 
 L 1 , L 2 , L 3 , and L 4  are amino acid linkers; 
   wherein the polypeptide of formula III and the polypeptide of formula [III] form a cross-over light chain-heavy chain pair; and   wherein V D1  and V D4 , or V D2  and V D3  comprise a heavy chain variable domain and a light chain variable domain of an antibody according to  claim 1 .   
     
     
         6 : The antibody-like binding protein according to  claim 3 , wherein the polypeptide of formula [I] further comprises a Fc domain (Fc 2 ). 
     
     
         7 : The antibody-like binding protein according to  claim 6 , comprising two polypeptide chains that form two antigen-binding sites, wherein one polypeptide chain has a structure represented by the formula [IV]:
   V D1 -L 1 -V D2 -L 2 -C L -L 5 -Fc 2   [IV]
   and one polypeptide chain has a structure represented by the formula [III]:
   V D3 -L 3 -V D4 -L 4 -C H1 -Fc  [III]
 
   wherein:
 V D1  is a heavy or light chain variable domain of a first immunoglobulin; 
 V D2  is a heavy or light chain variable domain of a second immunoglobulin; 
 V D3  is a heavy or light chain variable domain of said second immunoglobulin; 
 V D4  is a heavy or light chain variable domain of said first immunoglobulin; 
 C L  is a light chain constant domain of an immunoglobulin; 
 C H1  is a C H1  heavy chain constant domain of an immunoglobulin; 
 Fc is the immunoglobulin hinge region and CH 2 , CH 3  immunoglobulin heavy chain constant domains of an immunoglobulin; 
 Fc 2  is the immunoglobulin hinge region and CH 2 , CH 3  immunoglobulin heavy chain constant domains of an immunoglobulin; 
 L 1 , L 2 , L 3 , L 4  and L 5  are amino acid linkers; 
   wherein the polypeptide of formula [IV] and the polypeptide of formula [III] form a cross-over light chain-heavy chain pair; and   wherein V D1  and V D4 , or V D2  and V D3  comprise a heavy chain variable domain and a light chain variable domain of an antibody according to  claim 1 .   
     
     
         8 : The antibody-like binding protein according to  claim 4 , which comprises a third polypeptide chain comprising a Fc domain (F 3 ). 
     
     
         9 : The antibody-like binding protein according to  claim 8 , comprising three polypeptide chains that form two antigen-binding sites, wherein a first polypeptide has a structure represented by the formula [I]:
   V D1 -L 1 -V D2 -L 2 -C L   [I]
   and a second polypeptide has a structure represented by the formula [III]:
   V D3 -L 3 -V D4 -L 4 -C H1 -Fc  [III]
 
   and a third polypeptide Fc 3 , which is the immunoglobulin hinge region and CH 2 , CH 3  immunoglobulin heavy chain constant domains of an immunoglobulin;   wherein:
 V D1  is a heavy or light chain variable domain of a first immunoglobulin; 
 V D2  is a heavy or light chain variable domain of a second immunoglobulin; 
 V D3  is a heavy or light chain variable domain of said second immunoglobulin; 
 V D4  is a heavy or light chain variable domain of said first immunoglobulin; 
 C L  is a light chain constant domain of an immunoglobulin; 
 C H1  is a C H1  heavy chain constant domain of an immunoglobulin; Fc is the immunoglobulin hinge region and CH 2 , CH 3  immunoglobulin heavy chain constant domains of an immunoglobulin; 
 L 1 , L 2 , L 3 , and L 4  are amino acid linkers; 
   wherein the polypeptide of formula [I] and the polypeptide of formula [III] form a cross-over light chain-heavy chain pair;   wherein the polypeptide of formula [III] heterodimerizes with the third polypeptide through its Fc domain; and   wherein V D1  and V D4 , or V D2  and V D3  comprise a heavy chain variable domain and a light chain variable domain of an antibody according to  claim 1 .   
     
     
         10 : The antibody-like binding protein according to  claim 3 , wherein the antibody-like binding protein binds to at least one further target antigen. 
     
     
         11 : The antibody-like binding protein according to  claim 10 , wherein the at least one further antigen target is CD123. 
     
     
         12 : The antibody-like binding protein according to  claim 11 , wherein the antibody-like binding protein comprises:
 a) a light chain variable domain of a first immunoglobulin (V D1 ) consisting of the amino acid sequence SEQ ID NO: 9 or an amino acid sequence that is at least 85% identical thereto, a light chain variable domain of a second immunoglobulin (V D2 ) consisting of the amino acid sequence SEQ ID NO: 308 or an amino acid sequence that is at least 85% identical thereto, a heavy chain variable domain of the second immunoglobulin (V D3 ) consisting of the amino acid sequence SEQ ID NO: 312 or an amino acid sequence that is at least 85% identical thereto, and a heavy chain variable domain of the first immunoglobulin (V D4 ) consisting of the amino acid sequence SEQ ID NO: 5 or an amino acid sequence that is at least 85% identical thereto; or   b) light chain variable domain of a first immunoglobulin (V D1 ) consisting of the amino acid sequence SEQ ID NO: 21 or an amino acid sequence that is at least 85% identical thereto, a light chain variable domain of a second immunoglobulin (V D2 ) consisting of the amino acid sequence SEQ ID NO: 308 or an amino acid sequence that is at least 85% identical thereto, a heavy chain variable domain of the second immunoglobulin (V D3 ) consisting of the amino acid sequence SEQ ID NO: 312 or an amino acid sequence that is at least 85% identical thereto, and a heavy chain variable domain of the first immunoglobulin (V D4 ) consisting of the amino acid sequence SEQ ID NO: 18 or an amino acid sequence that is at least 85% identical thereto; or   c) a light chain variable domain of a first immunoglobulin (V D1 ) consisting of the amino acid sequence SEQ ID NO: 16 or an amino acid sequence that is at least 85% identical thereto, a light chain variable domain of a second immunoglobulin (V D2 ) consisting of the amino acid sequence SEQ ID NO: 308 or an amino acid sequence that is at least 85% identical thereto, a heavy chain variable domain of the second immunoglobulin (V D3 ) consisting of the amino acid sequence SEQ ID NO: 312 or an amino acid sequence that is at least 85% identical thereto, and a heavy chain variable domain of the first immunoglobulin (V D4 ) consisting of the amino acid sequence SEQ ID NO: 12 or an amino acid sequence that is at least 85% identical thereto; or   d) a light chain variable domain of a first immunoglobulin (V D1 ) consisting of the amino acid sequence SEQ ID NO: 26 or an amino acid sequence that is at least 85% identical thereto, a light chain variable domain of a second immunoglobulin (V D2 ) consisting of the amino acid sequence SEQ ID NO: 308 or an amino acid sequence that is at least 85% identical thereto, a heavy chain variable domain of the second immunoglobulin (V D3 ) consisting of the amino acid sequence SEQ ID NO: 312 or an amino acid sequence that is at least 85% identical thereto, and a heavy chain variable domain of the first immunoglobulin (V D4 ) consisting of the amino acid sequence SEQ ID NO: 23 or an amino acid sequence that is at least 85% identical thereto; or   e) a light chain variable domain of a first immunoglobulin (V D1 ) consisting of the amino acid sequence SEQ ID NO: 308 or an amino acid sequence that is at least 85% identical thereto, a light chain variable domain of a second immunoglobulin (V D2 ) consisting of the amino acid sequence SEQ ID NO: 143 or an amino acid sequence that is at least 85% identical thereto, a heavy chain variable domain of the second immunoglobulin (V D3 ) consisting of the amino acid sequence SEQ ID NO: 138 or an amino acid sequence that is at least 85% identical thereto, and a heavy chain variable domain of the first immunoglobulin (V D4 ) consisting of the amino acid sequence SEQ ID NO: 312 or an amino acid sequence that is at least 85% identical thereto; or   f) a light chain variable domain of a first immunoglobulin (V D1 ) consisting of the amino acid sequence SEQ ID NO: 158 or an amino acid sequence that is at least 85% identical thereto, a light chain variable domain of a second immunoglobulin (V D2 ) consisting of the amino acid sequence SEQ ID NO: 308 or an amino acid sequence that is at least 85% identical thereto, a heavy chain variable domain of the second immunoglobulin (V D3 ) consisting of the amino acid sequence SEQ ID NO: 312 or an amino acid sequence that is at least 85% identical thereto, and a heavy chain variable domain of a first immunoglobulin (V D4 ) consisting of the amino acid sequence SEQ ID NO: 171 or an amino acid sequence that is at least 85% identical thereto, or   g) a light chain variable domain of a first immunoglobulin (V D1 ) consisting of the amino acid sequence SEQ ID NO: 230 or an amino acid sequence that is at least 85% identical thereto, a light chain variable domain of a second immunoglobulin (V D2 ) consisting of the amino acid sequence SEQ ID NO: 158 or an amino acid sequence that is at least 85% identical thereto, a heavy chain variable domain of the second immunoglobulin (V D3 ) consisting of the amino acid sequence SEQ ID NO: 171 or an amino acid sequence that is at least 85% identical thereto, and a heavy chain variable domain of the first immunoglobulin (V D4 ) consisting of the amino acid sequence SEQ ID NO: 226 or an amino acid sequence that is at least 85% identical thereto; or   h) a light chain variable domain of a first immunoglobulin (V D1 ) consisting of the amino acid sequence SEQ ID NO: 385 or an amino acid sequence that is at least 85% identical thereto, a light chain variable domain of a second immunoglobulin (V D2 ) consisting of the amino acid sequence SEQ ID NO: 141 or an amino acid sequence that is at least 85% identical thereto, a heavy chain variable domain of the second immunoglobulin (V D3 ) consisting of the amino acid sequence SEQ ID NO: 138 or an amino acid sequence that is at least 85% identical thereto, and a heavy chain variable domain of the first immunoglobulin (V D4 ) consisting of the amino acid sequence SEQ ID NO: 383 or an amino acid sequence that is at least 85% identical thereto.   
     
     
         13 : The antibody-like binding molecule according to  claim 3 , which comprises:
 a) one polypeptide according to formula [I] consisting of the amino acid sequence SEQ ID NO: 388, which comprises V D1  of amino acid sequence SEQ ID NO: 385, L 1  of amino acid sequence SEQ ID NO: 389, V D2  of amino acid sequence SEQ ID NO: 141, L 2  of amino acid sequence SEQ ID NO: 389, and C L  of amino acid sequence SEQ ID NO: 310; or   a sequence that is at least 85% identical to the amino acid sequence SEQ ID NO: 388 in which the 3 CDRs of amino acid sequences SEQ ID NO: 378, WAS, and SEQ ID NO: 379 of V D1 , and the 3 CDRs of amino acid sequences SEQ ID NO: 142, KVS, and SEQ ID NO: 11 of V D2  are unaltered; and   b) one polypeptide according to formula [II] consisting of the amino acid sequence SEQ ID NO: 390, which comprises V D3  of amino acid sequence SEQ ID NO: 138, L 3  is 0 amino acids, V D4  of amino acid sequence SEQ ID NO: 383, L 4  is 0 amino acids and CH1 of amino acid sequence SEQ ID NO: 313, or   a sequence that is at least 85% identical to the amino acid sequence SEQ ID NO: 390 in which the 3 CDRs of amino acid sequences SEQ ID NO: 381, SEQ ID NO: 384, and SEQ ID NO: 382 of V D4 , and the 3 CDRs of amino acid sequences SEQ ID NO: 6, SEQ ID NO: 7, and SEQ ID NO: 8 of V D3  are unaltered; and   wherein the polypeptide of formula [I] and the polypeptide of formula [II] form a cross-over light chain-heavy chain pair.   
     
     
         14 : The antibody-like binding molecule according to  claim 7 , which comprises:
 a) one polypeptide according to formula [IV] consisting of the amino acid sequence SEQ ID NO: 391, which comprises V D1  of amino acid sequence SEQ ID NO: 385, L 1  of amino acid sequence SEQ ID NO: 389, V D2  of amino acid sequence SEQ ID NO: 141, L 2  of amino acid sequence SEQ ID NO: 389, C L  of amino acid sequence SEQ ID NO: 310, L 5  which is 0 amino acids, and Fc 2  of amino acid sequence SEQ ID NO: 392; or   a sequence that is at least 85% identical to the amino acid sequence SEQ ID NO: 391 in which the 3 CDRs of amino acid sequences SEQ ID NO: 378, WAS, and SEQ ID NO: 379 of V D1 , and the 3 CDRs of amino acid sequences SEQ ID NO: 142, KVS, and SEQ ID NO: 11 of V D2  are unaltered; and   b) one polypeptide according to formula [III] consisting of the amino acid sequence SEQ ID NO: 393, which comprises V D3  of amino acid sequence SEQ ID NO: 138, L 3  is 0 amino acids, V D4  of amino acid sequence SEQ ID NO: 383, L 4  is 0 amino acids, CH1 of amino acid sequence SEQ ID NO: 313, and Fc of amino acid sequence SEQ ID NO: 394; or   a sequence that is at least 85% identical to the amino acid sequence SEQ ID NO: 393 in which the 3 CDRs of amino acid sequences SEQ ID NO: 381, SEQ ID NO: 384, and SEQ ID NO: 382 of V D4 , and the 3 CDRs of amino acid sequences SEQ ID NO: 6, SEQ ID NO: 7, and SEQ ID NO: 8 of V D3  are unaltered; and   wherein the polypeptide of formula [IV] and the polypeptide of formula [III] form a cross-over light chain-heavy chain pair.   
     
     
         15 : The antibody-like binding molecule according to  claim 9 ; which comprises:
 a) one polypeptide according to formula [I] consisting of the amino acid sequence SEQ ID NO: 388, which comprises V D1  of amino acid sequence SEQ ID NO: 385, L 1  of amino acid sequence SEQ ID NO: 389, V D2  of amino acid sequence SEQ ID NO: 141, L 2  of amino acid sequence SEQ ID NO: 389, and C L  of amino acid sequence SEQ ID NO: 310; or   a sequence that is at least 85% identical to the amino acid sequence SEQ ID NO: 388 in which the 3 CDRs of amino acid sequences SEQ ID NO: 378, WAS, and SEQ ID NO: 379 of V D1 , and the 3 CDRs of sequences SEQ ID NO: 142, KVS, and SEQ ID NO: 11 of V D2  are unaltered; and   b) one polypeptide according to formula [III] consisting of the amino acid sequence SEQ ID NO: 395, which comprises V D3  of amino acid sequence SEQ ID NO: 138, L 3  is 0 amino acids, V D4  of amino acid sequence SEQ ID NO: 383, L 4  is 0 amino acids, CH1 of amino acid sequence SEQ ID NO: 313, and Fc of amino acid sequence SEQ ID NO: 396; or   a sequence that is at least 85% identical to the amino acid sequence SEQ ID NO: 395 in which the 3 CDRs of amino acid sequences SEQ ID NO: 381, SEQ ID NO: 384, and SEQ ID NO: 382 of V D4 , and the 3 CDRs of amino acid sequences SEQ ID NO: 6, SEQ ID NO: 7, and SEQ ID NO: 8 of V D3  are unaltered; and   c) one polypeptide Fc 3  which consists of amino acid sequence SEQ ID NO: 397, or a sequence that is at least 85% identical thereto, wherein said Fc 3  or the amino acid sequence that is at least 85% identical thereto heterodimerises with the Fc region of the polypeptide according to formula [III]; and   wherein the polypeptide of formula [I] and the polypeptide of formula [III] form a cross-over light chain-heavy chain pair.   
     
     
         16 : The antibody-like binding molecule according to  claim 9 , which comprises:
 a) one polypeptide according to formula [I] consisting of the amino acid sequence SEQ ID NO: 388, which comprises V D1  of amino acid sequence SEQ ID NO: 385, L 1  of amino acid sequence SEQ ID NO: 389, V D2  of amino acid sequence SEQ ID NO: 141, L 2  of amino acid sequence SEQ ID NO: 389, and C L  of amino acid sequence SEQ ID NO: 310; or   a sequence that is at least 85% identical to the amino acid sequence SEQ ID NO: 388 in which the 3 CDRs of amino acid sequences SEQ ID NO: 378, WAS, and SEQ ID NO: 379 of V D1 , and the 3 CDRs of amino acid sequences SEQ ID NO: 142, KVS, and SEQ ID NO: 11 of V D2  are unaltered; and   b) one polypeptide according to formula [III] consisting of the amino acid sequence SEQ ID NO: 399, which comprises V D3  of amino acid sequence SEQ ID NO: 138, L 3  is 0 amino acids, V D4  of amino acid sequence SEQ ID NO: 383, L 4  is 0 amino acids, CH1 of amino acid sequence SEQ ID NO: 313, and F-Fc of amino acid sequence SEQ ID NO: 400; or   a sequence that is at least 85% identical to the amino acid sequence SEQ ID NO: 399 in which the 3 CDRs of amino acid sequences SEQ ID NO: 381, SEQ ID NO: 384, and SEQ ID NO: 382 of V D4 , and the 3 CDRs of amino acid sequences SEQ ID NO: 6, SEQ ID NO: 7, and SEQ ID NO: 8 of V D3  are unaltered; and   c) one polypeptide Fc 3  which consists of amino acid sequence SEQ ID NO: 398, or a sequence that is at least 85% identical thereto, wherein said Fc 3  or the amino acid sequence that is at least 85% identical thereto heterodimerises with the F-Fc region of the polypeptide according to formula [III]; and   wherein the polypeptide of formula [I] and the polypeptide of formula [III] form a cross-over light chain-heavy chain pair.   
     
     
         17 : An isolated antibody that binds to the extracellular domain of human CD123 protein comprising:
 a) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 227 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 227 by one amino acid substitution; a CDR2-H of amino acid sequence SEQ ID NO: 228 or SEQ ID NO: 353 or SEQ ID NO: 279, or an amino acid sequence differing from amino acid sequence SEQ ID NO: 228 or SEQ ID NO: 353 or SEQ ID NO: 279 by one or more amino acid substitutions; and a CDR3-H of amino acid sequence SEQ ID NO: 229 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 229 by one amino acid substitution; and   a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 231 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 231 by one amino acid substitution; a CDR2-L of amino acid sequence RDD or an amino acid sequence differing from amino acid sequence RDD by one amino acid substitution; and a CDR3-L of amino acid sequence SEQ ID NO: 232 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 232 by one amino acid substitution; or   b) a heavy chain variable domain comprising a CDR1-H consisting of amino acid sequence X 1 YTFTDX 2 I (SEQ ID NO: 336) wherein X 1  is G or A and X 2  is H, Y or N, or any combination thereof; a CDR2-H consisting of amino acid sequence INPYSX 1 GX 2  (SEQ ID NO: 337) wherein X 1  is G or D and X 2  is T or A, or any combination thereof; and a CDR3-H consisting of amino acid sequence ALNYGSYYAMDA (SEQ ID NO 201); and   a light chain variable domain comprising a CDR1-L consisting of amino acid sequence X 1 DIX 2 X 3 N (SEQ ID NO: 338) wherein X 1  is E or K, X 2  is F, H or Y, and X 3  is N or S, or any combination thereof; a CDR2-L consisting of amino acid sequence DAN or DAS; and a CDR3-L consisting of amino acid sequence X 1 QYNX 2 YPYT (SEQ ID NO: 339) wherein X 1  is H or Q and X 2  is I, K or N, or any combination thereof; or   c) a heavy chain variable domain comprising a CDR1-H consisting of amino acid sequence GFSLTSYX 1  (SEQ ID NO: 340) wherein X 1  is H or S; a CDR2-H consisting of amino acid sequence MWX 1 DGDT (SEQ ID NO: 341) wherein X 1  is S or N; and a CDR3-H consisting of amino acid sequence ARGX 1 X 2 X 3 X 4 X 5 X 6 X 7 X 8 X 9 FX 10 Y (SEQ ID NO: 342) wherein X 1  is D, Y or H, X 2  is Y or R, X 3  is S or T, X 4  is S or P, X 5  is Y or no amino acid, X 6  is L, I or no amino acid, X 7  is Y or no amino acid, X 8  is L or no amino acid, X 9  is W or no amino acid, X 10  is A or D, or any combination thereof; and   a light chain variable domain comprising a CDR1-L consisting of amino acid sequence QSFLSSGDX 1 X 2 NY (SEQ ID NO: 343) wherein X 1  is E or G and X 2  is R or K, or any combination thereof; a CDR2-L consisting of amino acid sequence WAS; and a CDR3-L consisting of amino acid sequence QQYYDTPLT (SEQ ID NO: 253); or   d) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 206 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 206 by one amino acid substitution; a CDR2-H of sequence SEQ ID NO: 207 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 207 by one or more amino acid substitutions; a CDR3-H of amino acid sequence SEQ ID NO: 208 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 208 by one amino acid substitution; and   a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 210 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 210 by one amino acid substitution; a CDR2-L of amino acid sequence ETS or an amino acid sequence differing from amino acid sequence ETS by one amino acid substitution; and a CDR3-L of amino acid sequence SEQ ID NO: 211 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 211 by one amino acid substitution; or   e) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 213 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 213 by one amino acid substitution; a CDR2-H of amino acid sequence SEQ ID NO: 214 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 214 by one or more amino acid substitutions; and a CDR3-H of amino acid sequence SEQ ID NO: 215 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 215 by one amino acid substitution; and   a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 217 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 217 by one amino acid substitution; a CDR2-L of amino acid sequence NTN or an amino acid sequence differing from amino acid sequence NTN by one amino acid substitution; and a CDR3-L of amino acid sequence SEQ ID NO: 218 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 218 by one amino acid substitution; or   f) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 220 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 220 by one amino acid substitution; a CDR2-H of amino acid sequence SEQ ID NO: 221 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 221 by one or more amino acid substitutions; and a CDR3-H of amino acid sequence SEQ ID NO: 222 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 222 by one amino acid substitution; and   a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 224 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 224 by one amino acid substitution; a CDR2-L of amino acid sequence RVS or an amino acid sequence differing from amino acid sequence RVS by one amino acid substitution; and a CDR3-L of amino acid sequence SEQ ID NO: 225 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 225 by one amino acid substitution; or   g) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 234 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 234 by one amino acid substitution; a CDR2-H of amino acid sequence SEQ ID NO: 235 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 235 by one or more amino acid substitutions; and a CDR3-H of amino acid sequence SEQ ID NO: 236 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 236 by one amino acid substitution; and   a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 238 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 238 by one amino acid substitution; a CDR2-L of amino acid sequence GAS or an amino acid sequence differing from amino acid sequence GAS by one amino acid substitution; and a CDR3-L of amino acid sequence SEQ ID NO: 239 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 239 by one amino acid substitution; or   h) a heavy chain variable domain comprising a CDR1-H of amino acid sequence SEQ ID NO: 241 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 241 by one amino acid substitution; a CDR2-H of amino acid sequence SEQ ID NO: 242 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 242 by one or more amino acid substitutions; and a CDR3-H of amino acid sequence SEQ ID NO: 243 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 243 by one amino acid substitution; and   a light chain variable domain comprising a CDR1-L of amino acid sequence SEQ ID NO: 245 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 245 by one amino acid substitution; a CDR2-L of amino acid sequence YAS or an amino acid sequence differing from amino acid sequence YAS by one amino acid substitution; and a CDR3-L of amino acid sequence SEQ ID NO: 246 or an amino acid sequence differing from amino acid sequence SEQ ID NO: 246 by one amino acid substitution.   
     
     
         18 : An antibody-like binding protein that binds specifically to human CD123, comprising two polypeptide chains that form two antigen-binding sites, wherein a first polypeptide has a structure represented by the formula [I]:
   V D1 -L 1 -V D2 -L 2 -C L   [I]
   and a second polypeptide has a structure represented by the formula [II]:
   V D3 -L 3 -V D4 -L 4 -C H1   [II]
 
   wherein:
 V D1  is a heavy or light chain variable domain of a first immunoglobulin; 
 V D2  is a heavy or light chain variable domain of a second immunoglobulin; 
 V D3  is a heavy or light chain variable domain of said second immunoglobulin; 
 V D4  is a heavy or light chain variable domain of said first immunoglobulin; 
 C L  is a light chain constant domain of an immunoglobulin; 
 C H1  is a C H1  heavy chain constant domain of an immunoglobulin; 
 L 1 , L 2 , L 3 , and L 4  are amino acid linkers; 
   wherein the polypeptide of formula [I] and the polypeptide of formula [III] form a cross-over light chain-heavy chain pair; and   wherein V D1  and V D4 , or V D2  and V D3  comprise a heavy chain variable domain and a light chain variable domain of an antibody according to  claim 17 .   
     
     
         19 : A pharmaceutical composition comprising:
 a) an anti-CD123 antibody according to  claim 17 ; or   b) an anti-CD3 antibody according to  claim 1 ; and   c) a pharmaceutically acceptable carrier.   
     
     
         20 - 23 . (canceled) 
     
     
         24 : A method of treating or preventing a disease or disorder comprising administering to a subject in need thereof a therapeutically effective amount of:
 a) an antibody-like binding protein according to  claim 3 ; or   b) an anti-CD123 antibody according to  claim 17 ; or   c) an anti-CD3 antibody according to  claim 1 ; or   d) a pharmaceutical composition according to  claim 19 .   
     
     
         25 : An isolated nucleic acid comprising a nucleotide sequence encoding an antibody-like binding protein according to  claim 3 , an anti-CD123 antibody according to  claim 17 , or an anti-CD3 antibody according to  claim 1 . 
     
     
         26 : A host cell which has been transformed by a nucleic acid according to  claim 25 . 
     
     
         27 : A kit comprising at least one antibody according to  claim 1  and at least one antibody-like binding protein according to  claim 3 . 
     
     
         28 - 31 . (canceled) 
     
     
         32 : A method of treating or preventing a pathological immune response a in subject in need thereof, comprising administering to the subject a therapeutically effective amount of an anti-CD3 antibody according to  claim 1 . 
     
     
         33 : The method according to  claim 24 , wherein the disease or disorder is cancer. 
     
     
         34 : The method according to  claim 33 , wherein the cancer is a haematological cancer. 
     
     
         35 : A method for detecting ex vivo or in vivo CD123 expression in a biological sample of a subject, comprising contacting the biological sample with an antibody of  claim 17  and detecting specific binding of the antibody in the biological sample.