Correlation between direct binding ability of synthetic T. gondii SAG1 peptides to HLA-A2 measured by a sensor for surface plasmon resonance and antigenicity of the peptides for T. gondii-infected cell-specific CTL.

Toxoplasma gondii (T. gondii) -infected B lymphoma cells present T. gondii antigens in the context of major histocompatibility complex molecules to T. gondii-specific CD8+ cytotoxic T cells (CTL). HLA-A2 molecules of T. gondii-infected human cells have been shown to be used in presenting T. gondii antigens to CD8+ CTL. SAG1, one of the major antigenic molecules of T. gondii, is an antigen for T. gondii-specific CTL, and represents a possible basis for vaccines. The direct binding of nonamer SAG1 peptides to HLA-A2 was assayed here using an automated biosensor system with a sensor for surface plasmon resonance detection. The antigenicity of synthetic SAG1 peptides to T. gondii-specific CD8+ CTL also was assayed. The present study found a high correlation between the binding ability of synthetic SAG1 peptides to HLA-A2 and the antigenicity of peptides to T. gondii-infected cell-specific CD8+ CTL.