Cell surface phenotype of lymphoid cells from normal mice and mice treated with monoclonal anti-IgD from birth.

Mice treated from birth with mouse monoclonal anti-IgD antibodies develop low frequencies of B cells in the spleen, a small percentage of which express very low levels of sIgD on their cell surface and extremely low frequencies of B cells in their lymph nodes, lacking sIgD entirely. However, the splenic B cells are phenotypically mature in that a high percentage of these cells express Lyb-5, indicating that the expression of sIgD is not a prerequisite for the acquisition of a mature surface antigen repertoire of B cells. In contrast, a high density of sIgM on splenic B cells is expressed, which suggests a predominance of cells with the phenotype of immature B cells and/or activated B cells. Furthermore, the spleen cells from anti-IgD-treated mice lack cells that respond to in vitro stimulation by LPS with an increase in the density of their sIa.