Recombinant Leishmania major lipophosphoglycan 3 activates human T-lymphocytes via TLR2-independent pathway.

Leishmaniasis is one of the most common infectious diseases transmitted by an obligate intracellular genusLeishmania. As there is no efficient vaccination strategy for leishmaniasis, new immunostimulatory components may enhance protective immune responses against this parasite. Lipophosphoglycan 3 (LPG3) is an essential protein required for LPG assembling. In this study, the ability of recombinant LPG3 (rLPG) and its fragments to activate isolated healthy human T-cells and cytokine secretion was evaluatedin vitro. The results showed that rLPG3 and its N-terminal fragment (rNT-LPG3) enhanced expression of CD69 on the surface of T-cells and promoted differentiation of CD4+T-lymphocytes toward a T-helper 1 (TH1) phenotype, in part, through up-regulation of interferon (IFN)-γexpression in a TLR2-independent manner. These results indicated the protective effects of LPG3 (particularly NT-LPG3 fragment) as a potent immunostimulatory component ofleishmaniain vaccination against leishmaniasis. Further investigations inin vivoassays are clearly warranted. [ABSTRACT FROM AUTHOR]