Expression of a cDNA encoding a Toxoplasma gondii protein belonging to theheat-shock 90 family and analysis of its antigenicity

A cDNA clone (Tgzy85d11.r1) obtained from the Toxoplasma Expressed Sequence Tag project was chosen due to its homology with proteins of the heat shock 90 family. The cDNA encodes 137 amino acids of the C-terminal portion of t he Toxoplasma Hsp90 protein (TgHsp90). Serum samples obtained from orally i nfected BALB/c and C57BL/6 mice showed reactivity against a recombinant TgH sp90 (rTgHsp90) after 8 weeks postinfection. Isotype analysis showed an ant i-rTgHsp90 TgG2a/IgG3 response in infected BALB/c and anti rTgHsp90 IgG1/Ig G2a/IgG2b response in infected C57BL/B mice. Serum samples from individuals chronically and putative acutely infected with T. gondii showed a similar anti-rTgHsp90 IgG response. Our work identifies TgHsp90 as a novel parasite antigen that seems to elicit a higher relation of anti-TgHsp90/anti-T. gon dii IgGs during chronic infection in comparison with the acute stage. (C) 2 000 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.