Tissue Typing of Cells in Culture. II. Histocompatibility Typing of Diploid Fibroblastic Cultures by the Mixed Hemadsorption (MH) Test

Skin fibroblasts derived from persons who had been HLA-typed by conventional lymphocytotoxocity tests were subjected to HLA-typing by the mixed hemadsorption (MH) test. The agreement between the two methods was good, provided sera for the MH test were carefully selected. Minor discrepancies found in this study can probably be corrected by further serum selection. There was no difficulty in typing late passages of cultured diploid cells (22 doublings) and in fact it was easier to type a culture at the 33rd doubling than at the 11th. Thus no signs of disappearance of HLA-antigens were seen in these tests.