Immunomodulatory effects of crotoxin isolated from Crotalus durissus terrificus venom in mice immunised with human serum albumin

ABSTRACT

Crotalus durissus terrificus venom and its main component, crotoxin (CTX), have the ability to down-modulate the immune system. Certain mechanisms mediated by cells and solublefactors of the immune system are responsible for the elimination of pathogenic molecules to ensure the specific protection against subsequent antigen contact. Accordingly, weevaluated the immunomodulatory effects of CTX on the immune response of mice that had been previously primed by immunisation with human serum albumin (HSA). CTX inoculationafter HSA immunisation, along with complete Freund’s adjuvant (CFA) or Aluminium hydroxide (Alum) immunisation, was able to suppress anti-HSA IgG1 and IgG2a antibodyproduction. We showed that the inhibitory effects of this toxin are not mediated by necrosis or apoptosis of any lymphoid cell population. Lower proliferation of T lymphocytesfrom mice immunised with HSA/CFA or HSA/Alum that received the toxin wasobserved in comparison to the mice that were only immunised. In conclusion, CTX is able to exert potent inhibitory effects on humoural and cellular responses induced by HSAimmunisation, even when injected after an innate immune response has been initiated.