This study was carried out to investigate the immune response
against 97 kDa (p97) molecular marker of Toxoplasma gondii
that has been characterized as a cytosolic protein and a component of the excreted-secreted
antigens from this parasite. A total of 60 serum samples from patients were analyzed
by enzime-linked immunosorbent assay and Western blot for toxoplasmosis. These
samples were organized in three groups, based on clinical symptoms and results
of serological tests. Group I: 20 samples reactive to IgG and IgM (acute phase);
group II: 20 non-reactive samples (control group); and group III: 20 samples reactive
only to IgG (chronic phase). Western blot was performed with total antigenic extracts
or with excreted and secreted antigen from T. gondii
to identify the fraction
correspondent to p97. It was observed that this cytosolic component from T.
stimulates the immunologic system to produce both IgM and IgG antibodies
in the beginning of the acute infection and IgG throughout the chronic stage of
the asymptomatic toxoplasmosis.