Interleukin-1 but not tumour necrosis factor alpha synergistically upregulates the granulocyte-macrophage colony-stimulating factor-induced B7-1 expression of murine Langerhans cells

Epidermal Langerhans cells (LC) express several co-stimulatory molecules such as B7/BB1, which has been implicated as one of the important determinants for potent antigen-presenting function of LC. Recent studies have shown that B7/BB1 antigens comprise three distinct molecules termed B7-1, B7-2 and B7-3. Previous studies have revealed that the phenotypic and functional properties of murine LC are enormously affected by various cytokines including granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin-1 (IL-1), and tumour necrosis factor alpha (TNF-alpha) derived from surrounding keratinocytes. We have already demonstrated that the expression of B7-1 of murine LC is significantly enhanced by GM-CSF, IL-1 or TNF-alpha. In this paper, we present that IL-1, but not TNF-alpha, synergistically up-regulates the GM-CSF-induced B7-1 expression of murine LC.