The p150,95 molecule is a marker of human mononuclear phagocytes: Comparison with expression of class II molecules

Abstract

A new monoclonal antibody (mAb), named 3.9, is described that is specific for the p150,95 molecule, a member of the LFA-1, CR3, p150,95 family of human leukocyte differentiation antigens. The LFA-1 molecule participates in a variety of T cell interactions and the CR3 molecule is the receptor for the complement component iC3b, but little is known about the p150,95 molecule. Here we show that the expression of p150,95 is confined to myeloid cells. mAb 3.9 reacts variably with neutrophils, more strongly with monocytes and is most strongly expressed on tissue macrophages. Using this mAb and others, we have examined the heterogeneity of tissue macrophages. Cells such as Langerhans' cells, dendritic reticulum cells and osteoclasts failed to react with these mAb and thus, probably do not belong to the mononuclear phagocyte lineage. Using a new double-labeling technique, we investigated lymphoid tissue for dendritic cells bearing class II molecules which might function in interactions with T cells. In T cell areas macrophages expressing class II markers were seen but there was no evidence for other types of dendritic or interdigitating cells which expressed class II molecules but not macrophage epitopes. The conclusion from this survey was that the most prominent cell with dendritic morphology found in the T cell areas of lymphoid tissue was a macrophage.

The distinct leukocyte integrins of mouse spleen dendritic cells as identified with new hamster monoclonal antibodies.

“…Low levels of CD11c are expressed on human granulocytes and monocytes, and higher levels on macrophages that have been cultured long term or observed in tissue sections (31,32). However, the studies in man have not addressed the question of CDllc on dendritic cells.…”

All‐trans retinoic acid down‐regulates expression and function of β2 integrins by human monocytes: opposite effects on monocytic cell lines

“…Whether CD11 down-regulation on monocytes is secondary to differentiation (or rather dedifferentiation) is not known at present, but appears rather unlikely, since all three § chains are affected: CD11a has been reported to almost disappear from the cell surface during monocyte to macrophage maturation, while the opposite behavior has been shown for CD11c [33][34][35]. The effects of ATRA on integrin expression therefore appear to be of rather direct nature.…”

Macrophage heterogeneity in human fetal tissue. Fetal macrophages

“…1988). The almost complete lack of the leucocyte integrin molecule pi 50.95 on fetal cells is of particular interest, as this is a standard marker for adult tissue macrophages (Hogg et at., 1986). This result agrees with previous work on the fetal ileum where low pi 50.95 expression was observed (Spencer et at., 1987).…”