Serum protein from Leishmania brasiliensis infected hamster that suppress lymphocyte response of normal hamster lymphocytes.

Immunosuppression in Leishmania brasiliensis (LB) or L. donovani (LD) infected hamsters is correlated with the appearance of two serum protein bands found at 21, 60, 68 and 76 days post LB-infection and with eight bands at 21 days post-LD-infection probably of host origin. A protein band from LB-infected hamster serum isolated by electrofocusing, suppressed the blastogenic response of normal lymphocytes to T and B cell mitogens.