Analysis of human B cell response to recombinant Leishmania LPG3

AbstractObjectiveTo evaluate the capability of recombinant Leishmania LPG3 and its fragments in the activation of B cells.MethodsIn the present study, human B cells were purified from peripheral blood of 10 adult healthy subjects using magnetic-activated cell sorting technique. Subsequently, purified B cells were treated with recombinant LPG3, and its N-terminal and C-terminal fragments at different concentrations (2, 10 and 20 μg/mL). B cell activation was assessed through expression of CD69 molecule by flow cytometry and secretion of IL-6, TNF-α and IL-10 cytokines via enzyme-linked immunosorbent assay following treatment with recombinant antigens.ResultsOur results showed that while the recombinant LPG-3 could significantly increase the production of IL-6 and TNF-α (P < 0.05) in B cells, it had no effect on the secretion of IL-10 by B cells.ConclusionsOur study indicated that recombinant LPG-3 and especially its N-terminal fragment could stimulate B cell response as an important immune response component against leishmaniasis. Thus, it seems that it can be considered as an effective adjuvant in vaccine developments against leishmaniasis

Recombinant LPG3 Stimulates IFN-Γ and TNF-Α Secretion by Human NK Cells

Background:Natural killer (NK) cells play an important role in early stages of innate immune responses against viral and tumoral attacks. Activation of NK cells by leishmaniasis results in secretion of cytokines such as interferon (IFN)-γ and tumor necrosis factor (TNF)-α, which enhance the phagocytosis and clear­ance of parasite. Lipophosphoglycan 3 (LPG3), the Leishmania homologous with GRP94 (glucose regulated protein 94), a member of HSP90 family, contributes to LPG assembly as the most abundant macromolecule on the surface of Leishmania promastigotes. Methods:We purified NK cells from healthy individuals (n=10) using magnetic-activated cell sorting (MACS) technology. Purified NK cells were co-incubated with different concentrations of recombinant LPG3 (rLPG3), and its N-terminal (NT) and C-terminal (CT) fragments. Finally, the production of IFN-γ and TNF-α by NK cells were measured by ELISA. Results:Recombinant LPG3 but not its fragments (CT and NT), could signifi­cantly enhance the production of TNF-α by NK cells (P<0.05). Moreover, rLPG3, CT, and NT fragments were markedly stimulated the secretion of IFN-γ by NK cells (P<0.001). Conclusion: The Leishmania LPG3 antigen could effectively activate NK cells, in vitro. Leishmania LPG3 participates in the innate immunity against leishmaniasis and thereby improves the effective parasite destruction.However, its efficiency should be tested in vivo