Antibody-induced formation of caps inToxoplasma gondii

Summary Trophozoites ofToxoplasma gondii from mouse peritoneal exudate move their surface membrane antigens towards one pole of the cell when incubated with antibodies. The phenomenon may be induced in up to 50% of incubated parasites. It is prvented by some metabolic inhibitors and low temperatures (0–4°C). These properties do not change in parasites subpassaged after repeated incubation with antibodies.We wish to thank Dr. J.lusarczyk of the National Institute of Hygiene for his help in preparation the photomicropgraphs.