Chimeric recombinant antigens of toxoplasma gondii

Abstract

The invention described herein relates to a method for combining antigen fragments of Toxoplasma gondii proteins, in the form of chimeric fusion products, and their use as diagnostic and immunogenic agents.

1 - 31 . (canceled) 
     
     
         32 . A chimeric recombinant antigen containing a fusion of at least three different antigenic fragments of  Toxoplasma gondii  polypeptides, wherein said antigenic fragments are B-cell epitopes which bind to  Toxoplasma gondii -specific antibodies and wherein the three different antigenic regions have an amino acid sequence selected from the group consisting of: SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41 and SEQ ID NO: 42. 
     
     
         33 . The chimeric antigen of  claim 32 , wherein the  Toxoplasma gondii  specific antibodies are extracted from sera of subjects who have been infected by  Toxoplasma gondii.    
     
     
         34 . The chimeric antigen of  claim 32 , wherein the at least three different antigenic regions are linked by a covalent bond or by a peptide linker. 
     
     
         35 . A nucleotide sequence coding for the chimeric recombinant antigen of  claim 32 . 
     
     
         36 . The nucleotide sequence according to  claim 35 , comprising at least three different nucleotide sequences selected from the group consisting of: SEQ ID NO:1, SEQ ID NO:3, SEQ ID NO:5, SEQ ID NO:7, SEQ ID NO:9 AND SEQ ID NO:11. 
     
     
         37 . The nucleotide sequence according to  claim 35 , comprising the nucleotide sequence of SEQ ID NO:27. 
     
     
         38 . The nucleotide sequence according to  claim 35 , comprising the nucleotide sequence of SEQ ID NO:29. 
     
     
         39 . The nucleotide sequence according to  claim 35 , comprising the nucleotide sequence of SEQ ID NO:31. 
     
     
         40 . A nucleotide sequence that hybridizes under stringent hybridization conditions with a nucleotide sequence coding for the chimeric recombinant antigen of  claim 32 . 
     
     
         41 . The chimeric recombinant antigen encoded by the nucleotide sequence of  claim 40 . 
     
     
         42 . The nucleotide sequence of  claim 35 , which is a DNA sequence. 
     
     
         43 . A vector comprising the DNA sequence of  claim 42 . 
     
     
         44 . A host cell transformed with the vector of  claim 43 . 
     
     
         45 . The chimeric recombinant antigen according to  claim 32 , obtained by a process comprising
 culturing a host cell transformed with a vector comprising a nucleotide sequence that codes for the chimeric recombinant antigen of  claim 32  or that hybridizes under stringent hybridization conditions with a complement of a nucleotide sequence coding for the chimeric recombinant antigen of  claim 32 , and   isolating the chimeric recombinant antigen from the cultured host cells.   
     
     
         46 . A method for diagnosing a  Toxoplasma gondii  infection in a subject, the method comprising:
 contacting a chimeric recombinant antigen according to  claim 32  with a body component of the subject for a time and under condition to allow the chimeric antigen to form an antigen/antibody immune complex; and   detecting the antigen/antibody immune complex comprising the chimeric antigen.   
     
     
         47 . The method according to  claim 46 , wherein the  Toxoplasma gondii  infection is a congenital toxoplasmosis and the subject is an infant. 
     
     
         48 . The method according to  claim 46 , wherein the detecting of the antigen/antibody immune complex is indicative of a time of infection. 
     
     
         49 . A kit for diagnosis of a  Toxoplasma gondii  infection, containing at least one chimeric recombinant antigen according to  claim 32 . 
     
     
         50 . The kit of  claim 49 , wherein the kit is for the diagnosis of an acute and/or chronic  Toxoplasma gondii  infection.