Cell Surface Heterogeneity of Human Blood Neutrophils and Monocytes

Abstract

Human blood neutrophils (PMN) and monocytes were considered to be homogeneous cell populations. Recently, much evidence has accumulated on their functional heterogeneity. Apparently different subsets of myeloid cells analogous to T [thymus-derived] and B [bone marrow-derived] subsets of lymphoid cells exist. The question of myeloid subsets was investigated by examining myeloid cells for cell surface reactivity for Ig[immunoglobulin]G and complement (C). Normal PMN and monocytes were examined from 60 subjects for the presence of 2 types of IgG-Fc receptors and 2 activated C components, C3b and C3d. Most PMN and monocytes showed Fc receptor reactivity for rabbit IgG (Fc-R). The majority of monocytes but very few PMN reacted with human IgG (anti-Rh0) coated Rh-positive erythrocytes (Fc-H). Most PMN and monocytes showed C receptor reactivity for C3b, but only a minor subpopulation of both myeloid cells had C3d receptors. Human blood myeloid cells may be composed of subsets with different membrane marker reactivities.