TOXOPLASMA LYSATE ANTIGEN (TLA144)-IG8 ANTIGENIC COMPONENT - BINDING AND INDUCTION OF CYTOTOXIC-CELL ACTIVITY IN MOUSE SPLEEN-CELLS

The antigenic component TLA-Ig8 purified from Toxoplasma gondii-lysate antigen (TLA-144) using anti-TLA-144 and anti-TLA-Ig8 monoclonal anti bodies exhibited significant anti-tumor activity in methylcholanthrene tumor cell-bearing BALB/c mice. Binding activity of labelled TLA-Ig8 antigenic component to adherent cells was significantly higher relativ e to non-adherent cells, and reached a plateau approximately 30 minute s postincubation. Binding reaching a saturation point early on facilit ates the attachment of the antigen to the surface membrane receptor of adherent cells enhancing antigen processing through phagocytosis and thus inducing cytotoxic activity. Analysis of specific macrophage cell surface antigen revealed a molecule of molecular weight 80 kilodalton s. Our results suggest TLA-Ig8 antigenic component to be a tachyzoite surface antigen important In the induction of cytotoxic cell activity.