| Description |
Rat cell surface antigens were solubilized from D agouti (DA) strain rats by exposure of lymphoid cells to 3.0 M KC1. These extracts were shown to contain the private major locus antigen (Ag-B4), a species or xenoantigen, and a low molecular weight alloantigen of unknown origin. These antigenic specificities were separated by selective immunoabsorption and analytical polyacrylamide gel electrophoresis (PAGE). An immunosorbent column prepared with cyanogens bromide-activated Sepharose-4B and the DEAE globulin fraction from Fi and anti-DA antiserum separated xeno- and major alloantigen, indicating that these specificities are present as separate entities on rat lymphoid cell membranes. In addition, the Ag-B4 antigen which had bound to the immunosorbent column was eluted with 2 M KC1, labeled with 125I and shown in sodium dodecylsulfate (SDS) PAGE to be a highly purified homogenous group of molecules. The molecular weight of AG-B4 was shown to be 30-35,000 daltons, and its amino acid composition was determined. On the basis of these data, it appears the Ag-B antigens are homologous to HL-A and H-2 antigens. An additional cell surface antigen was isolated Ag-X. The molecular weight of this antigen was estimated in SDS PAGE to be 10-20,000 daltons. The physical as well as immunological properties of this antigen do not resemble those of any known antigenic product of the major histocompatibility locus of the rat. Ag-x, therefore, appears to be a rat minor histocompatibility antigen. |
