An ultrastructural and cytochemical study of Tritrichomonas foetus-eosinophil interaction.

The fine structure of the process of interaction between uncoated and antibody-coated Tritrichomonas foetus with rat peritoneal eosinophils was studied. Eosinophils were purified by discontinuous Metrizamide gradient. Agglutination and immunofluorescence microscopy showed that T.foetus grown in a medium supplemented with different kinds of serum, antibodies present in it opsonize the parasites. Parasites incubated in the presence of anti-T.foetus rabbit serum attach to and are ingested by eosinophils. No such attachment was observed with trypsin-treated parasites. Attachment of antibody-coated parasites to the eosinophils induced their degranulation with the release of granule contents onto parasite surface causing its destruction. Hyperimmune serum was shown to be required for both attachment and ingestion of the parasites. The cytochemical localization of basic proteins and peroxidase showed that leucocyte granules fused with parasite-containing phagocytic vacuoles. Images were obtained suggesting that the binding of the parasites to the eosinophil surface triggers an exocytic process with release of the granule content onto the parasite surface.

Fine structure and cytochemistry of Tritrichomonas foetus and rat neutrophil interaction.

The fine structure of normal and antibody-coated Tritrichomonas foetus cells and their interaction with rat peritoneal neutrophils was studied. Peritoneal neutrophils were obtained by glycogen stimulation. The neutrophils readily associated with and killed the parasites, which were subsequently ingested. The process involved activation of the respiratory burst, as demonstrated by the use of cytochemical methods. Images were obtained indicating that binding of parasites to the neutrophil surface triggers an exocytic response with release of oxygen-derived products. Cytochemical localization of acid phosphatase and peroxidase activities showed that leukocyte granules fused with the parasite-containing phagocytic vacuoles. We also showed the cytochemical localization of alkaline phosphatase in the parasite-neutrophil interaction.

The interaction of Tritrichomonas foetus and Trichomonas vaginalis with macrophages.

The process of interaction between macrophages and Tritrichomonas foetus and Trichomonas vaginalis was analysed using light microscopy, scanning and transmission electron microscopy. The parasites attach to the macrophage surface and are ingested through a phagocytic process. Parasite-macrophage association index was higher for activated than for resident macrophages. Previous incubation of the parasites in the presence of Concanavalin A rendered their surface less negative and more hydrophobic, as evaluated by measurement of the zeta potential and contact angle, respectively. This treatment significantly increased parasite ingestion by resident, but not activated macrophages.