Keratinocyte-derived T-cell growth factor: a T-cell growth factor functionally distinct from interleukin 2.
T-cell growth factor, more recently termed interleukin 2 (IL-2), is the product of activated T lymphocytes and is considered the principal trophic factor for T lymphocytes. The activity of IL-2 preparations is assessed by the degree to which they support the growth of various IL-2-dependent cell lines. We report that murine epidermal epithelial cells (keratinocytes) produce and release a factor that supports the growth of the helper-T-cell-derived, IL-2-dependent cell line HT-2. This substance, keratinocyte-derived T-cell growth factor (KTGF), does not support the growth of an IL-2-dependent cell line derived from cytotoxic T cells (line CTLL-2). This differential effect on IL-2-dependent cell lines is unique to KTGF. KTGF has an apparent molecular weight of 25,000-35,000 and has properties similar to those of conventional IL-2 by reversed-phase and gel-filtration HPLC analysis. However, even highly purified KTGF fails to stimulate the proliferation of CTLL-2 cells. The observation that epidermal epithelium produces a trophic factor for T lymphocytes may help explain the basis for preferential proliferation of T cells in the microenvironment of skin in certain dermatologic disorders. Further, it suggests that different IL-2-dependent T-cell lines may have distinct growth requirements and that non-lymphocyte cell types may produce factors capable of maintaining the growth of T cells.
D000818:Animals; D001688:Biological Products; D002455:Cell Division; D002460:Cell Line; D016207:Cytokines; D004817:Epidermis / Q000502:physiology*; D004848:Epithelium / Q000502:physiology; D007376:Interleukin-2 / Q000302:isolation & purification; D051379:Mice; D008970:Molecular Weight
D001688:Biological Products; D016207:Cytokines; D007376:Interleukin-2