MODULATION OF CELL-SURFACE EGF RECEPTOR AND HLA EXPRESSION ON GLIOMA CELL-LINES INDUCED WITH CYTOKINES AND DIFFERENTIATION PROMOTORS

Alterations of cell surface expression of HLA (class I, class II DR, DP and DQ) and EGF-receptor on two malignant glioma cell lines (U-343MG and U-563MG) induced with cytokines (IFN-gamma, TNF-alpha, IL-1 alpha) and differentiation promoters (all-trans retinoic acid, phorbol ester TPA) were analyzed with tire aid of flow cytometry. IFN-gamma induced a 10-15fold increase of HLA class I. TNF-alpha alone induced a two- to fivefold increase of HLA class I cell surface density and increased the IFN-gamana induced upregulation of HLA class I to approximately 20-24 times the antigen density of uninduced cells. TNF-alpha was able to increase KLA class II DR and DP cell surface expression on glioma lines, but it enhanced only the IFN-gamma-induced HLA class II DR upregulation. All-trans retinoic acid and TPA regulated in the opposite way the EGF-receptor cell surface expression on U-563MG cells.