Expression of binding sites for peanut agglutinin during murine B lymphocyte differentiation.

Haemopoietic cells from several murine organs were examined for the presence of peanut agglutinin (PNA) receptors. Foetal liver and adult bone marrow contained a number of cells, which were PNA+ but did not stain with conventional T and B markers. Some of the PNA+ cells, however, were pre-B cells, as shown by the presence of cytoplasmic IgM in the absence of cell surface Ig. Cells in the T lineage retained their PNA receptors during maturation, although these became masked by sialic acid on mature peripheral blood T cells. Cells of the B lineage, in contrast, gradually lost their PNA receptors as they matured from pre-B to mature surface immunoglobulin positive B lymphocytes.