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IgE receptors on human lymphocytes III. Expression of IgE receptors on mitogen‐stimulated human mononuclear cells

1986; Wiley; Volume: 16; Issue: 9 Linguagem: Inglês

10.1002/eji.1830160903

1521-4141

Guy Delespesse, M Sarfati, M Rubio-Trujillo, Terry Wolowiec,

Mast cells and histamine

Abstract Human peripheral blood mononuclear cells (PBMC) were tested for the expression of Fee‐receptor (FcεR) after stimulation with various mitogens in the absence of IgE. FcεR were found on virtually all the cells from 19 Epstein‐Barr virus‐transformed B cell lines including those derived from cord blood, from one agamma‐globulinemic patient and VDS‐0 pre‐B cells. Hence, the data clearly indicate that FcεR may be expressed on very immature B cells. PBMC cultures stimulated with either pokeweed mitogen (PWM), phytohemagglutinin (PHA) or concanavalin A displayed an early increase of their content in FcεR‐bearing cells followed by a decrease to levels below those of the control cultures. After fractionation of the PWM‐stimulated cultures into T and B cell‐enriched preparations, most of the FcεR + cells were in the B cell fractions and the same low levels of FceR + cells were found in the T cell fractions isolated from the PWM‐stimulated and from the control cultures. Double‐labeling experiments, employing biotinylated F(ab') 2 monoclonal antibody to FcR and either fluorescein isothiocyanate‐conjugated B1 or Mo2 monoclonal antibodies, indicated that PWM mainly exerted its effect on B cells and on monocytes. This effect was T cell dependent and it was mediated by soluble factors of T cell origin. At the peak of the PHA or concanavalin A response, most of the FceR‐bearing cells were found in the B cell fraction but the T cells isolated from mitogen‐stimulated cultures contained significantly more FcεR + cells than those from the control cultures, suggesting that T cell mitogens had increased the expression of FcεR on some T cells. This view was supported by the finding of a higher proportion of FceR + cells in PHA‐stimulated than in control cultures of highly purified T cells with a maximum response at the end of the culture period. Double‐labeling experiments at the peak (day 2) of the peripheral blood mononuclear cell response indicated that the expression of FcεR was increased on B cells (Bl + ) and on monocytes (Mo2 + ). By using the same approach at the peak of the T cell response (day 7), it was found that T cells isolated from PHA‐stimulated cultures expressed more FcεR than those isolated from control cultures. Moreover, in unstimulated cultures, FcεR was mainly expressed on T helper cells (Leu 3 + ) whereas in PHA‐stimulated cultures FcεR was expressed on both T helper and T suppressor/cytotoxic cells (Leu 2 + ).