CHANGED INFECTIVITY OF GAMMA EXPOSED Leishmania donovani: LIGHT MICROSCOPIC VIEW

The use of γ-irradiated live attenuated Leishmania donovani parasites as a potential therapeutic agent against visceral leishmaniasis enhance the long-lasting protective immunity to host. Promastigotes of L. donovani exposed to gamma radiation (Co60 Source, Gammacell 220) at 20krad resulted in significant parasitisation of mononuclear phagocytic system in vivo and in vitro. Irradiation at this dose revealed altered parasitisation and optimum infection after acquiring the shape of amastigote-like organism. Few of them engulfed by macrophages and rest of the parasite remained side by side in the field as if they could not recognize the macrophages. Morphologic changes of L. donovani such as shrinkage of cytoplasm, loss of flagellum and progressive loss of motility, all were induced by 20 krad Gamma radiation (1.33MeV).