B-cell-derived human interleukin 1.

This review addresses the questions of the molecular nature and of the physiological role of interleukin-1 (IL-1)-like activities produced by B lymphocytes. IL-1 was originally described as an exclusive product of activated monocytes/macrophages. The recent cloning of two genes for IL-1 (IL-1 alpha and beta), together with the availability of specific antibodies to these two species of IL-1 have allowed their identification as secretory products of a number of other cell types, including B cells. B cells secrete a variety of other autostimulatory factors and of IL-1-like molecules, the identification of which is still pending. In addition, B cells express receptors for IL-1, which has been shown to enhance proliferation and immunoglobulin synthesis. An important issue is that of whether B-cell-derived IL-1 serves a purpose in the physiology of the immune response. Inasmuch as IL-1 is required for T-cell response, it has been suggested that B-cell-derived IL-1 may contribute to the amplification of the immune response, particularly where B lymphocytes serve as antigen-presenting cells.