Papel da BjcuL, uma lectina isolada do veneno da serpente Bothrops jararacussu, na resposta imunológica mediada por linfócitos T

Abstract

BjcuL is a type C lectin that depends on calcium ions to develop its biological activities. This protein is composed of two identical subunits that constitute the homodimer molecular structure. BjcuL has specificity for carbohydrate binding through its CDR region and exhibits hemagglutinating activity, inhibits proliferation of tumor cells, as well as the formation of bacterial biofilms. The purpose of this study was to investigate the effect of BjcuL under the human T lymphocyte mediated immune response and its different subpopulations. Results showed that BjcuL is not toxic to PBMCs and also does not exert mitogenic activity on these cells at concentrations of 5 and 10 μg/mL which can be regulated by the reactive oxygen species (ROS). The data evidenced that T lymphocytes are the cells responsible for ROS production induced by BjcuL, which contributes to the non-mitogenic activity for this lectin. BjcuL-FITC interacted with monocytes, B lymphocytes, Natural Killer cells and with subpopulations of T lymphocytes. The result of this interaction was the cellular activation that induced the production of pro-inflammatory cytokines such as IL-6 and TNF-α, and antiinflammatory cytokine such as IL-10. In addition, the data showed that the cells responsible for TNF-α production are mainly Natural Killer cells and monocytes, whereas IL-10 is produced by CD4+ T cells and Treg lymphocytes when stimulated by BjcuL. The cytokine profile produced by the cells when stimulated by this lectin allows us to confirm that BjcuL develops immunomodulatory activity. The results obtained may serve as a basis for the development of new drugs of clinical interest and as tools for biotechnological prospecting.