Entry of Trypanosoma (Schizotrypanum) dionisii to macrophages in vitro and its subsequent fate therein.

Observations by phase contrast, fluorescence and electron microscopy showed that epimastigotes of Trypanosoma (Schizotrypanum) dionisii (grown in vitro) were phagocytosed posterior end first by mouse peritoneal macrophages in vitro. Many were subsequently digested as a result of phagosome-lysosome fusion but others survived by apparently inhibiting this fusion and/or escaping from the phagosome into the host cell's cytoplasm. These survivors replicated as amastigotes. Long trypomastigotes, separated from populations grown in vitro by passage down a column of glass beads (with or without prior exposure to guinea-pig serum), were phagocytosed by either pole and all were subsequently digested.