title: Chimaeric anti-CD4 monoclonal antibody cross-linked by monocyte Fc gamma receptor mediates apoptosis of human CD4 lymphocytes.
abstract: Previous studies have shown that murine anti-CD4 monoclonal antibody, cross-linked by rabbit anti-mouse immunoglobulin, could mediate apoptosis of murine CD4+ lymphocytes when they were stimulated by T cell receptor antibody. In this study, we have shown that the murine anti-CD4 monoclonal antibody, OKT4, can induce apoptosis in human CD4+ T cells stimulated by the recall antigen tuberculin purified protein derivative (PPD) only when cross-linked by rabbit anti-mouse immunoglobulin. The chimeric anti-CD4 monoclonal antibody, cM-T412 whose Fc fragment is human, was able to cause apoptosis without cross-linking by a second antibody. Similarly, abolition of PPD-induced proliferation of peripheral blood mononuclear cells by cM-T412 did not require cross-linking with rabbit anti-human immunoglobulin. Inhibition of proliferation by cM-T412 could be reduced by pre-treating monocytes with heat-aggregated human IgG. This suggested that monocyte Fc gamma receptors might be cross-linking the human Fc of cM-T412. Propidium iodide staining together with immunofluorescence showed that the apoptotic cells were indeed CD4+ lymphocytes. It is proposed that during treatment with cM-T412 in autoimmune disease such as rheumatoid arthritis, cM-T412-coated CD4 T cells, when they are subsequently stimulated by the unknown arthritogenic antigen, may undergo apoptotic cell death through cross-linking of cM-T412 on Fc gamma receptor-positive cells within the joint.
authors.affiliation: Division of Medicine, United Medical School, Guy's Hospital, London, GB.
authors.forename: E H
authors.initials: EH
authors.lastname: Choy
authors.forename: J
authors.initials: J
authors.lastname: Adjaye
authors.forename: L
authors.initials: L
authors.lastname: Forrest
authors.forename: G H
authors.initials: GH
authors.lastname: Kingsley
authors.forename: G S
authors.initials: GS
authors.lastname: Panayi
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D017209:Apoptosis / Q000276:immunology*; D015704:CD4 Antigens / Q000378:metabolism*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D003432:Cross-Linking Reagents; D004247:DNA / Q000378:metabolism; D006801:Humans; D008213:Lymphocyte Activation; D051379:Mice; D017452:Receptors, IgG / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000276:immunology; D014373:Tuberculin / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D003432:Cross-Linking Reagents; D017452:Receptors, IgG; D011993:Recombinant Fusion Proteins; D014373:Tuberculin; D004247:DNA