EXPRESSION OF ANTIGENS IN VIRULENT AND AVIRULENT INDIAN STRAINS OF LEISHMANIA-DONOVANI

Indo-Gen mediated surface labelling with I-125 demonstrated difference s in surface oriented antigens between virulent and avirulent promasti gotes of Leishmania donovani. In case of virulent strains, surface pol ypeptides with molecular masses of 63, 53, 42 and 35 kDa were found to be labelled with I-125 whereas in the case of avirulent stains 68, 55 , 50, 46, 42 and 38 kDa components were iodinated. Further studies by immunoblot assay using different subcellular Fractions of virulent and avirulent parasites demonstrated that antibody raised against gp63 cr oss-reacted with the 63 and 60 kDa antigen of the virulent and avirule nt Leishmania donovani strains of Indian origin respectively. It indic ates that these two polypeptides are antigenically similar, When virul ent and avirulent cells were grown in the presence of varying concentr ation of tunicamycin and immunoblotted with anti gp63, it was observed that with increasing concentration of tunicamycin the 63 kDa polypept ide of the virulent cells shifted to approximately 58-57 kDa and the 6 0 kDa polypeptide of the avirulent cells shifted to 57 kDa. This sugge sts that glycosylation may play an important role in antigenic variati on between virulent and avirulent parasites.