Influência do BCG (Bacillus Calmette-Guérin) na maturação de células dendríticas humanas diferenciadas a partir de monócitos

Abstract

Dendritic cells (DCs) play a crucial role in the immune system. They are derived from monocyte differentiation and have been utilized in cancer immunotherapy. Previous studies have demonstrated the maturation of DCs with live BCG, but for models targeting immunosuppressed patients, the maturation of DCs with killed BCG needs to be investigated. This study aims to compare the in vitro maturation of DCs by BCG with TNF-α as a reference, evaluating phenotypic expression, cytokine production, the influence on T lymphocyte cytokine production, and the ability to induce lymphocyte proliferation. The DCs were differentiated from monocytes isolated from the blood of healthy donors and matured with killed BCG (DC-BCG) or TNF-α and IFN-α (DC-TNF). After terminal maturation, the phenotype of these cells was investigated. Under both conditions, high expression levels of markers such as HLA-DR, CD1A, and CD86 were observed, with a significant increase in CD80 expression seen only in DC-TNF (p<0.05). Regarding MFI (mean fluorescence intensity) levels, a significant difference was observed in HLA-DR levels, which were higher in DCTNF compared to DC-BCG (p<0.05). Cytokine production by DCs revealed a more pronounced pro-inflammatory profile in DC-TNF, with higher levels of IP10, IL-8, and RANTES. These cells were further co-cultured with autologous and allogeneic lymphocytes for five days to evaluate their ability to induce lymphocyte proliferation. The supernatant was collected at 24 and 48 hours of culture for cytokine quantification. DC-BCG induced greater lymphocyte proliferation in both autologous (11% vs. 5%) and allogeneic (21% vs. 16%) cultures and also promoted greater production of cytokines associated with Th1 profiles in stimulated lymphocytes (IFN-γ, IL-2), Th2 (IL-4, IL-13), and Th17 (IL-17a). The results suggest that killed BCG is effective in DC maturation, promoting an amplified immune response compared to TNF-α. This potential reinforces the use of DC-BCG in immunotherapy, especially in immunosuppressed patients.