Murine immunoglobulin G anti-CD4 monoclonal antibodies bind to primary human monocytes and macrophages through Fc receptors as well as authentic CD4.
Using Western blot and fluorescence-activated cell sorter (FACS) analysis, we demonstrated that primary human monocytes and culture-derived macrophages express low levels of authentic CD4 antigen. The plasma membrane Fc receptor (FcR) on mononuclear phagocytes plays a major role in the binding of murine immunoglobulin G2 alpha anti-CD4 monoclonal antibody (MAb), and contributes to binding of other subclasses. The FcR detected shows an increase in apparent molecular weight from 60 to 70 kD over 2 weeks in culture. U937 cells resemble T lymphocytes, rather than primary monocytes/macrophages, in expressing relatively high levels of CD4; FcR contributes little to the signal. The potential bivalent interactions between immunoglobulin G and receptors such as CD4 and FcR could influence the binding and fate of HIV in primary monocytes/macrophages.
Teppler
H
H
Sir William Dunn School of Pathology, University of Oxford, UK.
Lee
S H
SH
Rieber
E P
EP
Gordon
S
S
D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D001665:Binding Sites; D015153:Blotting, Western; D015704:CD4 Antigens / Q000276:immunology* / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D066298:In Vitro Techniques; D008264:Macrophages / Q000276:immunology; D051379:Mice; D009000:Monocytes / Q000276:immunology; D011961:Receptors, Fc / Q000378:metabolism*; D015728:Receptors, HIV / Q000276:immunology / Q000378:metabolism
D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D007074:Immunoglobulin G; D011961:Receptors, Fc; D015728:Receptors, HIV