Normal human keratinocytes grown in
MCDB 153 plus bovine pituitary extract and treated with recombinant
gamma interferon (rIFN-gamma) express
HLA-DR, DP and DQ
antigens. The expression of these class II MHC
antigens is time dependent: DR and DP appear before DQ. The delay in
HLA-DQ expression is not due to the effects of trypsinization of cultures prior to analysis. Increasing the
calcium ion concentration from 0.1 to 1.8 mM does not alter the expression of these
antigens. Keratinocytes grown without
serum proteins or bovine pituitary extract exhibited markedly delayed expression of DR. By contrast, keratinocytes grown in Dulbecco's modified Eagle's medium (DMEM) plus 10%
fetal calf serum express DR and DP but only very small amounts of DQ
after treatment with rIFN-gamma. Expression of
HLA-DR occurs at doses of rIFN-gamma that are too low to cause growth inhibition. The cells of the
squamous cell carcinoma cell line SCL-1, whether grown in
MCDB 153 plus bovine pituitary extract or DMEM plus 10%
fetal calf serum, express
HLA-DQ and DP on only small numbers of cells
after treatment with the lymphokine. Thus, the conditions of culture, possibly the presence of a serum factor(s), influence the expression of
class II antigens in normal keratinocytes. Furthermore, rIFN-gamma does not induce DP and DQ
antigens readily in transformed squamous cells cultured in either serum-containing or serum-free medium.