Characterization of in Vitro Cultivated Amastigote like of Leishmania major: A Substitution for in Vivo Studies

Background: Promastigotes of Leishmania spp. have been readily cultured, but the axenic culture of amastigotes has been successful in L. donovani, L .infantum L. mexicana and L. pifanoi. However, some species such as L. major, is much less amenable to axenic cultivation. In present study, we describe an in vitro culture system for the generation and propagation of axenic amastigotes form of L. major.Methods: Promastigotes of L. major were cultivated in a biphasic NNN medium. The liquid phase was Schneider's medium, pH 3.5, supplemented by 25% FCS (fetal calf serum). The cultures were maintained at 33-34°C for 120 hours. Results: Fine structure analysis of these in vitro-grown amastigotes by electron microscopy, demonstrated that they have a pear-shaped body with abortive short terminal flagellum. The in vitro-grown cells are agglutinated by peanut lectin. SDS-PAGE pattern of these axenic amastigotes showed a 66-kDa band, which was not present in promastigotes. The axenic grown amastigotes were able to infect peritoneum macrophages of BALB/c mice. In supernatant of culture, biochemical, analysis showed decreased protein and acid phosphate activity. Conclusion: These amastigotes like cells might serve as a suitable strain for the study of amastigote biochemistry, in vitro drug testing, and immunology of L. major