Induction of transcription factors, miRNAs and cytokines involved in T lymphocyte differentiation in BCG-vaccinated subjects

•Modulation of TBET and FOXP3 expression following the administration of the vaccine.•Both IL-10 and IFN-γ indicate a state of protection induced by the vaccine.•BCG induces a downregulation of miR-146a, miR-326, and miR-155 at 6 months.•High production of multifunctional cells CD4+TNF-α+IL-10+IFN-γ-. The BCG vaccine induces a Th1 phenotype, which is essential for protection against Mycobacterium tuberculosis. However, the effects of BCG vaccination over time on the T helper subpopulation and the microRNAs involved in adulthood have not been studied. In the present study, we explored the involvement of microRNAs, transcription factors and multifunctional cytokines in BCG vaccination by examining their levels both before and after vaccination of healthy adults. Peripheral blood mononuclear cells were obtained at 0, 2 and 6 months after vaccination. Cells were cultured in the presence or absence of ESAT-6 and CFP-10 or M. tuberculosis filtrate. The expression levels of miRNAs and transcription factors were evaluated using qRT-PCR. Cytokine production in supernatants and serum samples was evaluated using ELISA. Multifunctional CD4+ T cells were analyzed using multiparametric flow cytometry. We observed a decrease in the expression levels of T-BET, GATA3 and FOXP3 at 2 months and miR-146a, miR-326 and miR-155 at 6 months after receiving the vaccine. In the supernatant, the production of IL-17 was increased after 6 months, with both stimuli. In contrast, IL-10, TNF-α and IFN-γ increased at 2 months. In the serum, high levels of IL-10 were found after 2 months compared to time 0 and 6 months. The production of multifunctional cells that expressed the cytokine profiles CD4+TNF-α+IFN-γ-IL-10-, CD4+TNF-α+IL-1IFN-γ-, CD4+IL-10+IFN-γ-TNF-α- and CD4+IL-17+IFN-γ- predominantly increased after 2 months with and without the stimulus. Correlation analysis revealed a negative association between FOXP3 and miR-155 (r=−0.5120, p=0.0176) and between IL-17 and miR-326 (r=−0.5832, p=0.0364). This study is the first to demonstrate roles for microRNAs, transcription factors and cytokines in the T helper differentiation lineage and to describe the possible mechanism by which their expression is modulated by the presence of the BCG vaccine in adulthood. In conclusion, our results suggest that the BCG vaccine induces a modulation in transcription factors and miRNAs with high production of multifunctional cells CD4+TNF-α+IL-10+IFN-γ-.