[The virulence and cytochemical properties of Leishmania major during long-term cultivation].

It has been shown that morphogenesis of Leishmania major in each culture passage is characterised by the depletion of RNA and increase in its dispersion degree, by the change of the NADP-H-diaphorese, peroxidase and Janus green-B-oxidative activity in the promastigotes. Cytochemical peculiarities of invasive metacyclic promastigotes are an extreme depletion of RNA, its disperse form, a low activity of oxidative enzymes. This properties may manifest the pre-adaptation of Leishmania promastigotes to the development in vertebrate host. In the process of long-term cultivation of L. major the virulence, the metacyclogenesis, and the level of NADF-H-diaphorase and peroxidase activity decrease from passage to passage, but the ability to oxidate the Janus green-B increases.