title: Interleukins 18 and 12 synergistically upregulate interferon-gamma production by murine dendritic epidermal T cells.
abstract: A unique subset of gammadelta T cells, termed dendritic epidermal T cells, reside in murine epidermis. It was previously reported that freshly isolated dendritic epidermal T cells and dendritic epidermal T cell lines expressed mRNA for interferon-gamma. Recent studies indicated that interleukin-18, a novel cytokine which strongly induces interferon-gamma production by T cells, was produced by murine keratinocytes and Langerhans cells. Interleukin-12, which is regarded as a key cytokine for Th1 type helper clone responses, has also been reported to be produced by these cells in murine skin. In this study, we demonstrated by enzyme-linked immunosorbent assay that interleukin-18 and interleukin-12 synergistically upregulated interferon-gamma production by dendritic epidermal T cells in short-term cultures. This was the case in both C57/BL6 mice and BALB/C mice, although the quantity of interferon-gamma produced was different in the two mouse strains. Interleukin-18 or interleukin-12 alone did not induce interferon-gamma production by dendritic epidermal T cells. Interferon-gamma mRNA was only weakly detected by the semiquantitative reverse transcriptase-polymerase chain reaction method in freshly isolated dendritic epidermal T cells, and the mRNA expression was much increased 12 h after stimulation with interleukin-18 and interleukin-12. We also confirmed biologic activity of interferon-gamma produced by dendritic epidermal T cells by showing upregulation of major histocompatibility complex class II expression on Pam 212, murine keratinocyte cell line. Thus, this study suggests that interleukin-18 and interleukin-12 produced by keratinocytes and Langerhans cells regulate interferon-gamma production by dendritic epidermal T cells and thus may play important parts in the regulation of immune responses in skin-associated lymphoid tissues.
authors.affiliation: Department of Dermatology, University of Tokyo, Japan. sugaya-tra@h.u-tokyo.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Sugaya
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.forename: K
authors.initials: K
authors.lastname: Tamaki
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004357:Drug Synergism; D000078404:Epidermal Cells; D004817:Epidermis / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000235:genetics; D018664:Interleukin-12 / Q000494:pharmacology*; D020382:Interleukin-18 / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D012333:RNA, Messenger / Q000032:analysis; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000032:analysis; D013601:T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000949:Histocompatibility Antigens Class II; D020382:Interleukin-18; D012333:RNA, Messenger; D016692:Receptors, Antigen, T-Cell, gamma-delta; D018664:Interleukin-12; D007371:Interferon-gamma