Pam3CSK4 enhances adaptive immune responses to recombinant Mycobacterium bovis bacille Calmette-Guérin expressing Plasmodium falciparum C-terminus merozoite surface protein-1

Objective: To determine the effects of toll-like receptor 2(TLR-2) agonist, Pam3 CSK4, on cellular and humoral immune response against recombinant Mycobacterium bovis bacille Calmette-Guérin(rBCG) expressing the C-terminus of merozoite surface protein-1 of Plasmodium falciparum.Methods: Six groups of mice(n=6 per group) received intraperitoneal phosphate buffered saline T80(PBS-T80), BCG or rBCG in the presence or absence of Pam3 CSK4. Enzymelinked immunosorbent assay was carried out to measure serum total IgG, IgG1, IgG2 a, and Ig G2 b production. Spleens were also harvested and splenocytes were co-cultured with rBCG antigen for in vitro determination of IL-4 and IFN-γ via enzyme-linked immunosorbent assay.Results: The production of total IgG and the isotype IgG1, IgG2 a and IgG2 b was significantly higher in rBCG-immunised mice than in the BCG and PBS-T80-immunised mice, and Pam3 CSK4 further enhanced their productions. A similar pattern was also observed in IFN-γ production. Moreover, there was no significant difference in IL-4 production in all groups either in the presence or absence of Pam3 CSK4.Conclusions: We present evidence of the adjuvant effects of TLR-2 agonist in enhancing the production of total IgG, IgG1, IgG2 a, IgG2 b, as well as IFN-γ in response to rBCG. However, the presence or absence of Pam3 CSK4 had no effect on IL-4 production.