Study of HLA-DR synthesis in cultured XXXX keratinocytes.

@entity1 @entity1503 @entity379 @entity460 @entity1199
Within the normal @entity1 epidermis only Langerhans and indeterminate cells express HLA-DR. @entity1 keratinocytes (HK), however, may also express HLA-DR in certain disease states characterized by mononuclear cell infiltrates. Previous studies have shown that HK synthesize HLA-DR in response to stimulation by @entity379 ). The purposes of this study were to define conditions under which cultured HK might express HLA-DR and to compare the HLA-DR synthesis of HK with that of monocytes. HLA-DR expression by HK as determined by indirect immunofluorescence of HK cultures was absent under standard low @entity460 conditions and remained absent with the addition of @entity460 , serum, mitogens, and supernatants from Pam-212 cells containing epidermal thymocyte-activating factor. HLA-DR expression in HK was induced by cocultivation with concanavalin A-stimulated peripheral blood mononuclear cells (PBMC), but not unstimulated PBMC. This effect was time-dependent and directly related to the number of PBMC. HLA-DR expression was also induced in a time- and dose-dependent manner by addition of @entity1503 ( @entity1503 ) or by addition of recombinant INF-gamma but not by addition of interleukin (IL)-1 or @entity1199 . Induction by either @entity1503 or INF-gamma was blocked by an antiserum to INF-gamma. As determined by a semiquantitative immunoprecipitation technique, HLA-DR synthesis by HK was directly related to INF-gamma concentration. The pattern of HLA-DR peptides produced by HK was similar to that of monocytes, but the relative quantity synthesized was far less than that of monocytes.
