TRANSFORMATION, DEVELOPMENT, AND TRANSMISSION OF AXENICALLY CULTURED AMASTIGOTES OF LEISHMANIA-MEXICANA IN-VITRO AND IN LUTZOMYIA-LONGIPALPIS

Axenic cultures of Leishmania mexicana amastigotes were transformed to promastigotes in vitro and in vivo in Lutzomyia longipalpis. In vitro , both exponential phase and stationary phase amastigotes were capable of transforming and growing as promastigotes, but exponential phase a mastigotes completed this transition more quickly. in vivo, both popul ations were capable of establishing infections in sand flies by membra ne feeding and could be transmitted to BALB/c mice via bite. A variety of morphologic forms could be observed in vivo, including putative me tacyclic promastigotes. Infection rates in sandflies with axenic amast igotes were comparable with those achieved with lesion-derived amastig otes, supporting the use of these cultured forms in studies of parasit e biology.