Effects of long-term in vitro cultivation on Leishmania donovani promastigotes.
Promastigotes of Leishmania donovani that had been subcultured in modified Tobie's medium for 2 to 3 years showed decreased infectivity and lack of virulence for hamsters and mice compared to newly transformed promastigotes. Amastigotes derived from these long-term promastigote cultures decreased in number rapidly in hamsters, but only slightly in mice, over a 48-day period. In cultured mouse and hamster macrophages infected in vitro, amastigotes derived from long-term cultures rapidly decreased to low numbers, which persisted. The same pattern was seen in macrophages treated with catalase, an inhibitor of the oxygen-dependent killing mechanism of the macrophage. Promastigotes from long-term cultures also differed from virulent first-passage promastigotes in size, growth patterns in Tobie's medium, and in the quantities of some of their antigens.
D000818:Animals; D000953:Antigens, Protozoan; D002374:Catalase / Q000494:pharmacology; D002478:Cells, Cultured; D006224:Cricetinae; D003470:Culture Media; D005260:Female; D066298:In Vitro Techniques; D007891:Leishmania / Q000254:growth & development* / Q000276:immunology / Q000472:pathogenicity; D007898:Leishmaniasis, Visceral / Q000469:parasitology; D008099:Liver / Q000469:parasitology; D008264:Macrophages / Q000469:parasitology; D008297:Male; D051379:Mice; D013154:Spleen / Q000469:parasitology; D013997:Time Factors; D014774:Virulence
D000953:Antigens, Protozoan; D003470:Culture Media; D002374:Catalase