Figure 1: Schematic representation of the immune effects of vitamin D: this figure depicts the principal innate and adaptive immune responses to an antigenic challenge and the influence of vitamin D (positive regulation: increase or negative regulation: decrease) on these responses (B cell: B lymphocyte, cyto T cell, cytotoxic T cell, DC: dendritic cell, MΦ: macrophage T cell: T lymphocyte; TLR: toll-like receptor; TH: helper T cell; Treg: regulatory T cell; IL: interleukin; TNF: tumor necrosis factor; and INF: interferon).