Axenic promastigote forms of Leishmania (Viannia) lainsoni as an alternative source for Leishmania antigen production.

The present study demonstrates that axenic cultures of Leishmania (Viannia) lainsoni produce larger cell masses in NNN-LIT medium, as well as higher amounts of total proteins in cell extracts, than Leishmania (Leishmania) amazonensis. Antigenicity of L. (V.) lainsoni whole promastigotes is similar to that of L. (L.) amazonensis, as demonstrated by an indirect immunofluorescence diagnostic test using sera from human patients and dogs infected with visceral leishmaniasis. Infectivity of the L. (V.) lainsoni strain used in the present work was demonstrated by the detection by transmission-electron microscopy of tissue amastigotes in skin lesion samples from an experimentally infected hamster. Incubation of lesion fragments in NNN-LIT medium allowed us to obtain promastigote forms, which could be cultivated successfully in vitro. lsoenzyme analysis of such promastigotes confirmed the parasite strain as L. (V.) lainsoni, as compared to other Leishmania reference strains. Our data indicate that L. (V.) lainsoni is a useful alternative source for antigen production as well for use in assays that depend on large cell volumes of Leishmania spp. parasites.