Cellular expression of the non-HLA-DR B-cell antigen 7420: studies on non-lymphoid cells and on lymphocytes from...

We recently reported on a heterologous antiserum (antiserum 7420), raised against chronic lymphocytic leukaemic lymphocytes, that reacts with B-lymphocyte antigen(s) different from known B-cell markers such as HLA-DR (Ia-like) antigens, surface immunoglobulin, and the Fc receptor. This antiserum is now shown to react also with a C3-receptor-positive population of lymphocytes from the dog, monkey, ox and sheep but not from rodents and avians. The antiserum does not react with the non-lymphoid human cells mature granulocytes, thrombocytes, erythrocytes, or spermatozoa, nor with the cultured cell lines tested, i.e. fibroblasts, melanoma cells, HeLa cells and green monkey kidney cells. This reactivity pattern differs somewhat from that reported for HLA-DR antiserum. The antigen(s) defined by the 7420 antiserum and the C3 receptor are different, since they redistribute independently on the lymphocyte surface.