MEMBRANE-BOUND ANTIBODIES TO BLOOD-STREAM TRYPANOSOMA-CRUZI IN MICE - STRAIN DIFFERENCES IN SUSCEPTIBILITY TO COMPLEMENT-MEDIATED LYSIS

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  • 1 January 1979
    • journal article
    • research article
    • Vol. 37  (3) , 416-423
Abstract
The Y, CL and other strains of Trypanosoma cruzi display different morphological and immunological characteristics. The interaction of bloodstream forms of different strains of T. cruzi with components of the complement [C] system is described. The bloodstream forms of the Y and B strains but not those of the CL strain are lysed by normal human serum. Lysis is mediated by combined activities of the alternative and classical C pathways. These activities are triggered by antibodies [Ab] on the surface of the parasites as shown by binding of flurescein or radiolabeled anti-mouse immunoglobulin [Ig] to the parasite''s membrane and the finding that bloodstream forms from lethally irradiated mice can be sensitized and rendered susceptible to C-mediated lysis by incubation with sera from acutely infected animals. Bloodstream forms of the CL strain bear surface Ig and sensitizing Ab are present in the sera of the mice infected with this strain. CL trypomastigotes from acutely infected mice fail to be lysed by human or mouse C unless the parasites are pre-incubated with sera from chronically infected animals. The basis of the different interactions between CL and Y trypomastigotes with Ab and the C system and their biological significance are discussed.