Annotating genes with potential roles in the immune system: six new members of the IL-1 family

Analysis of the human genome sequence and other DNA databases is proceeding at a rapid pace, and immunologists are playing an important role in the effort to ascribe functions to putative gene products. An excellent, recent example is the description of six gene sequences predicted to encode homologs of interleukin-1 (IL-1), named IL-1F5–IL-1F10. Indications of a possible role for these homologs in immunity and inflammation are starting to emerge. Most are expressed in monocytes, macrophages and/or dendritic cells; IL-1F5 and IL-1F9 are expressed strongly in keratinocytes; and the expression of IL-1F9 is induced in skin during contact hypersensitivity and in psoriasis patients. IL-1F7 and IL-1F10 bind to the soluble type I IL-1 receptor (IL-1RI) and IL-18R, respectively. Specific functions for these proteins are currently being sought.