Regulatory variants for the expression of h-2 antigens. i. isolation and characterization

By subjecting “mutagenized” mouse myeloma cells repeatedly to selection with antiserum against H-2K^d, we isolated variants that expressed little or no H-2K^d alloantigens. The phenotype was unstable, with the culture accumulating revertants in the absence of selective pressure. The variants not only failed to express the selected antigen, but also the antigen coded by the closely linked H-2D^d gene. The cells reexpressed this antigen with the same kinetics as for the selected antigen. Several physiologic parameters (karyotype, cell morphology, size, and growth curves) were not altered by the loss of H-2 antigens. However, when injected iv, the H-2-deficient cells did not lodge in the spleen as readily as did the wild-type cell.