TLR9 signalling mediates the activation of both innate and adaptive humoral and cellular immunity against viral and bacterial infections by promoting cellular proliferation and differentiation into antibody-secreting cells, upregulating molecules involved in immune cellular interactions, and increasing secretion of proinflammatory (IL6, TNFα, and type I interferons) and immune regulatory (IL10) cytokines [25, 26]. This evidence concerns the gene TLR9 and bacterial infectious disease.