HIV-1 Peptides, Nucleic Acids, and Compositions and Uses Thereof

Abstract

This invention features polypeptides, variants thereof, and fragments thereof useful in eliciting an immune response (e.g., neutralizing antibodies) against abroad spectrum of HIV-I isolates. The polypeptides, variants, and fragments include a portion of the gp120 V2 domain of HIV-I. The polypeptides, variants, and fragments display an epitope that is recognized by at least one antibody which neutralizes at least one HIV-I primary isolate. This invention also features nucleic acid sequences encoding those polypeptides. In addition, the invention provides methods of screening for inhibitors of HIV-I entry into cells, as well as methods of treatment using the inhibitors.

1 . An isolated polypeptide, consisting of:
 (a) an amino acid sequence EIKNC SFNXT TXXRD KXXXX YXLFY XLDXV (SEQ ID NO:1); or   (b) a fragment of the sequence, wherein the fragment comprises amino acids 14-20 of SEQ ID NO:1; or   (c) a fragment of the sequence, wherein the fragment comprises at least six consecutive amino acids of SEQ ID NO:1 and includes at least two of the residues at positions 14-16 and at least two of the X residues at positions 17-20,   wherein the X at position 9 of SEQ ID NO:1 is M or I;   the X at position 12 of SEQ ID NO:1 is S, E, G, or N;   the X at position 13 is L, I, or M;   the X at position 17 of SEQ ID NO:1 is K, R or Q;   the X at position 18 of SEQ ID NO:1 is K, R, or Q;   the X at position 19 of SEQ ID NO:1 is K, R or Q;   the X at position 20 of SEQ ID NO:1 is E or V;   the X at position 22 of SEQ ID NO:1 is S or A;   the X at position 26 of SEQ ID NO:1 is K or R; and   the X at position 29 of SEQ ID NO:1 is I or V.   
     
     
         2 . The polypeptide of  claim 1 , selected from the group of
 a) wherein the X at position 17 is K; the X at position 18 is Q; the X at position 19 is K; and the X at position 20 is V (KQKV, SEQ ID NO:3);   b) wherein the X at position 17 is K; the X at position 18 is Q; the X at position 19 is K; and the X at position 20 is E (KQKE, SEQ ID NO:4);   c) wherein the X at position 17 is K; the X at position 18 is K; and the X at position 19 is K (KKK);   d) wherein the X at position 17 is K; the X at position 18 is R; and the X at position 19 is Q (KRQ);   e) wherein the X at position 17 is K; the X at position 18 is K; and the X at position 19 is Q (KKQ); or   f) wherein the X at position 17 is K; the X at position 18 is Q; and the X at position 19 is Q (KQQ).   
     
     
         3 . An isolated protein comprising the polypeptide of  claim 1 , and flanked at either end, or both ends, by a heterologous amino acid sequence. 
     
     
         4 . The isolated polypeptide of  claim 1 , wherein the polypeptide is glycosylated. 
     
     
         5 . (canceled) 
     
     
         6 . A pharmaceutical composition comprising the polypeptide of  claim 1  and a pharmaceutically acceptable carrier. 
     
     
         7 . An isolated antibody, or antigen-binding fragment thereof, that specifically binds to a polypeptide consisting of SEQ ID NO:6 at an epitope comprising one or more of the amino acid residues at positions 14-19 of SEQ ID NO:1. 
     
     
         8 . The isolated antibody of  claim 7 , wherein the residues at positions 17-20 of SEQ ID NO:1 are selected from of KQKE (SEQ ID NO:4) or KQKV (SEQ ID NO:3). 
     
     
         9 . An isolated antibody that crossblocks the binding of the antibody of  claim 7 . 
     
     
         10 . The isolated polypeptide of  claim 1 , wherein the polypeptide, when administered to a mammalian subject, elicits the production by the subject of an antibody that has cross-neutralizing activity against HIV-1. 
     
     
         11 . An isolated nucleic acid encoding the polypeptide of  claim 1 . 
     
     
         12 . A vector comprising the nucleic acid sequence of  claim 11 . 
     
     
         13 . (canceled) 
     
     
         14 . A method of stimulating the production of an antibody in a mammalian subject, the method comprising
 delivering to a mammalian subject a composition comprising the polypeptide of  claim 1 .   
     
     
         15 - 19 . (canceled) 
     
     
         20 . The method of  claim 14 , further comprising delivering one or more additional polypeptides to the subject, wherein each of the one or more additional polypeptides is a polypeptide consisting of:
 (a) an amino acid sequence EIKNC SFNXT TXXRD KXXXX YXLFY XLDXV (SEQ ID NO:1); or   (b) a fragment of the sequence, wherein the fragment comprises amino acids 14-20 of SEQ ID NO:1; or   (c) a fragment of the sequence, wherein the fragment comprises at least six consecutive amino acids of SEQ ID NO:1 and includes at least two of the residues at positions 14-16 and at least two of the X residues at positions 17-20, wherein   the X at position 9 of SEQ ID NO:1 is M or I;   the X at position 12 of SEQ ID NO: 1 is S, E, G, or N;   the X at position 13 is L, I, or M;   the X at position 17 of SEQ ID NO: 1 is K, R or Q;   the X at position 18 of SEQ ID NO: 1 is K, R, or Q;   the X at position 19 of SEQ ID NO: 1 is K, R or Q;   the X at position 20 of SEQ ID NO: 1 is E or V;   the X at position 22 of SEQ ID NO: 1 is S or A;   the X at position 26 of SEQ ID NO: 1 is K or R; and   the X at position 29 of SEQ ID NO:1 is I or V.   
     
     
         21 . The method of  claim 1 , wherein the mammalian subject is a human. 
     
     
         22 . The method of  claim 14 , wherein the polypeptide comprises a single-chain epitope fused to a T-helper amino acid sequence. 
     
     
         23 - 24 . (canceled) 
     
     
         25 . A method of inhibiting infection of a cell by HIV-1, the method comprising contacting a cell or an HIV-1 virus with the polypeptide of  claim 1 . 
     
     
         26 . (canceled) 
     
     
         27 . A method of treating a subject that is infected, is suspected of being infected, or is likely to be infected with HIV-1, the method comprising delivering to a subject the pharmaceutical composition of  claim 6 . 
     
     
         28 - 29 . (canceled) 
     
     
         30 . A method of immunizing a human subject with an immunogen consisting or containing the polypeptides of  claim 1 , together with appropriate adjuvants and carriers, in order to induce an antibody response that protects against infection by HIV. 
     
     
         31 . A method of immunizing a human subject with an immunogen consisting or containing the polypeptides of  claim 1 , together with appropriate adjuvants and carriers, where the specific sequence of the V2-CND polypeptide is identical or highly related to the sequence of the corresponding region in a virus or HIV-1 Env gene isolated directly from the same patient. 
     
     
         32 . An isolated protein comprising the polypeptide of  claim 1 , and flanked at either end, or both ends, by additional gp120-derived amino acid sequences that normally flank this region in one or more viral isolates.