Immunomodulatory activity of Trypanosoma cruzi recombinant antigen combination TSA-1-C4 and Tc24-C4 induce activation of macrophages and CD8+ T cells

Chagas disease is a chronic infection caused by the protozoan parasite, Trypanosoma cruzi, with limited benefits of the currently available anti-parasitic chemotherapeutic approaches to halt the progression of heart disease. Recombinant TSA-1-C4 and Tc24-C4 proteins have been developed as promising antigen candidates for therapeutic vaccines, leading to propose them in combination as a bivalent recombinant protein strategy. In this study, we evaluated the immunomodulatory effect of the combined TSA-1-C4 and Tc24-C4 recombinant proteins by in vitro assays using murine macrophages. Macrophages from naive Balb/c mice were isolated and stimulated with TSA-1-C4 plus Tc24-C4 recombinant proteins, hence, supernatants were recovered to measure host NO, H2O2, as well as, TNF-alpha, IL-1 beta, IL-6 and IL-10 cytokine responses. Later, stimulated macrophages were co-cultured with CD8(+) T cells from naive mice, and inflammatory cytokine-profiles were measured from supernatants. We observed that combining both antigens promotes the activation of host macrophages by NO and H2O2 release; moreover, these macrophages also induced considerable pro-inflammatory immune-responses mediated by TNF-alpha, IL-1 beta and IL-6 cytokines compared to either TSA-1-C4 or Tc24-C4 stimulated macrophages. In addition, naive CD8(+) T cells in presence of TSA-1-C4 plus Tc24-C4 stimulated-macrophages similarly boosted the pro-inflammatory immune profile by significant production of IFN-gamma and TNF-alpha cytokines. These results support immunological advantages for the use of TSA-1-C4 and Tc24-C4 combination as vaccine candidates against T. cruzi.