Maturation-linked expression of C3b and C3b' receptors on developing human bone marrow and peripheral blood granulocytes.

The sequential expression of granulocyte membrane receptors for C3b, C3b' and C3d have been investigated in normal human bone marrow and peripheral blood. In particular the relationship between receptor expression and morphological characteristics of granulocyte maturation has been assessed. The result indicate that C3b receptor development precedes that of the Fc-IgG receptor and is present on all neutrophil precursors with the exception of the agranular myeloblast. Furthermore, there is, in contrast to Fc-IgG receptors, no difference (P greater than 0.35) in C3b receptor expression between marrow and peripheral blood segmented neutrophils. An apparent subpopulation of granulocytes also appear to have receptors for C3b' whereas receptors for C3d were not detected at all during granulocyte maturation. The application of these findings to the normal in vivo functions of granulocytes and to the study of abnormal granulocyte populations in myeloproliferative disorders is discussed.