The Interaction Between Human Monocytes and Red Cells

Abstract

Red cells coated with IgG globulin are bound circumferentially about a central mononuclear cell or monocyte into a "rosette" (1). Attached red cells appear deformed and closely resemble the abnormal red cell morphology frequently observed in the peripheral blood of patients with Coombs positive hemolytic anemia associated with IgG antibodies. Although in some studies the monocyte receptor was specific for IgG globulin without specificity for the third component of complement (C3) (1, 2), in others a receptor for C3 (3, 4) as well as a nonspecific receptor (5) have been described. We report here confirmation of the IgG specificity of the mononuclear cell receptor for rosette formation. A C3 receptor for rosette formation was not observed. Some of the well described biologic functions of the Fc fragment of IgG globulin reside in selective IgG subclasses (6). IgG subclass specificity for rosette formation is described in this report in addition to studies which further delineate the peptide portion of the Fc fragment of IgG that binds to the monocyte. 1 Materials and MethodsProteins.--Sera containing high titers of anti-D were obtained from patients with Rh incompatibility as a result of pregnancy and from one individual previously immunized. These anti-D antibodies were warm-active IgG globulins. Sera containing cold agglutinins (anti-l) were derived from patients who had mycoplasma pneumonia or from individuals with "idio-

Immunologic characterization of the mononuclear cell infiltrates in rheumatoid synovia, in rheumatoid nodules, and in lip biopsies from patients with sjö;ugren's syndrome

“…The latter receptor is recognized by the formation of rosettes with sheep red blood cells coated with antibody and complement (EAC). Monocytes, histiocytes, and macrophages also have C3 receptors (7) but differ from B lymphocytes in that they have an additional receptor for cytophilic antibody which will bind sheep red blood cells coated with IgG (EA 7s) (7,8). B lymphocytes do not react with EA 7s cells but do react with EAC cells (37,38).…”

“…Recent developments in the field of cellular immunology have now permitted differentiations of different types of mononuclear cells (1)(2)(3)(4)(5)(6)(7). Human lymphocytes may be classified, based upon animal experiments and studies in patients with immunodeficiency states, into at least two groupsthymic-dependent lymphocytes (T cells) and thymicindependent or bone marrow-derived lymphocytes (B cells) (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). T cells are thought to mediate reactions of cellular immunity, whereas B cells are primarily concerned with humoral immunity (14,15).…”

Receptors for human immunoglobulin on acute myeloid leukaemic leucocytes

“…It is thus significant that the Gm'0 allotype is restricted to the IgG3 sub-class (Martensson and Kunkel, 1965) whilst the Gm' and Gm2 allotypes are restricted to IgGl (Terry, Fahey and Steinberg, 1965; for review see Grubb, 1970). Other workers have shown that whilst IgGI and IgG3 are efficient in-hibitors, both of the phagocytosis of antibody-coated erythrocytes by monocytes (Huber and Fudenberg, 1968) and HEA rosetting by lymphocytes, (Fr0land et al, 1974a), IgGl is much less efficient than IgG3 in attaching to leucocyte Fc receptors (Abramson et al, 1970b).…”

“…The spectrum of cells in the peripheral blood of acute myeloid leukaemic patients is far larger than in normal peripheral blood, and changes in the percentage of HEA-RFC in AML (Dickler and Kunkel, 1972) Abramson et al (1970b), who showed in addition that Fc fragments and y-1 and y-3 H-chains inhibited rosetting by leucocytes, whilst y-4 H-chain was less inhibitory, and Fab, F(ab')2 and albumin were almost non-inhibitory. Other authors (Messner andJelinek, 1970, Fr0land et al, 1974a) have observed similar inhibition of HEA-RFC, but Dickler and Kunkel (1972) (Dickler and Sachs, 1974).…”

“…That the receptor recognizes the Fc fragment of IgG has been demonstrated by the inhibition of IgG binding to cells by isolated Fc but not Fab or F(ab')2 fragments (Abramson et al, 1970b;Messner and Jelinek, 1970;Fr0land et al, 1974a). Although Fc receptors are important for the phagocytosis of antigen-antibody complexes by monocytes and macrophages, Fudenberg, 1968, Huber, Douglas andFudenberg, 1969) and in antibody-dependent lymphocyte-mediated cytotoxicity (Dickler, 1974;Wisl0ff, Fr0land and Michaelson, 1974) the functional significance of Fc receptors in vivo still remains unclear.…”