β₂-Microglobulin from serum associates with several class I antigens expressed on the surface of mouse L-cells

Bovine β₂-microglobulin (β2-m) present in fetal calf serum (FCS) is able to replace endogenous β2-m associated with several class I antigens from human and mouse cells maintained in culture [Bernabeu et al. (1984) Nature, Lond. 308, 642-645]. Here we show that human HLA-A2 and HLA-B7, as well as mouse H-2L^d and H-2D^d heavy chains expressed after gene transfer in mouse L-cells, associate to a large extent with bovine β2-m. We also demonstrate that bovine β2-m associated with the endogenous H-2K^k/D^k heavy chains generates an antibody response when L-cells are injected into syngeneic C3H mice.