Search

Tritrichomonas foetus, the agent of bovine trichomoniasis, is a flagellate protozoan responsible for substantial economic losses to the dairy and calf industries worldwide. As yet, there is no approved treatment nor is there a sensitive diagnostic method. All these problems suggest that immunization is the best control strategy. In view of this, we isolated and partially purified flagella of the parasite by vortex homogenization followed by low-speed differential centrifugation. The resulting enriched flagellar preparation termed "crude flagellar prep" was purified further by sucrose and percoll gradients. Microscopic analysis showed that the flagellar membrane was intact. Analysis by sodium dodecyl-sulfate polyacrylamide gel electrophoresis revealed three prominent protein bands of 42, 49, and >250 kDa, and several minor bands. Immunoblotting of flagellar and whole-cell extracts revealed many flagellar antigens.

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.