Recombinant interleukin-4 promotes expression of the CD25 (Tac) antigen at the plasma membrane of high-density human tonsillar B lymphocytes.
High-density human B lymphocytes were prepared from tonsillar mononuclear cells by depletion of adherent cells and T lymphocytes, followed by discontinuous density gradient centrifugation. The B cells were analysed for the levels of expression of the CD25 (Tac) antigen marker by flow cytometry following culture with a variety of cytokines. IL-4 could induce elevated levels of CD25 on high-density, putatively resting B lymphocytes in a dose-dependent fashion. Expression of CD25 at the B-cell surface could not be promoted by interleukin-2 (IL-2), interferon-gamma (IFN-gamma) or by a crude preparation of B-cell growth factor 2 (BCGF-2). Mitogenic challenge of the B cells with pokeweed mitogen (PWM) and a combination of phorbol ester and calcium ionophore were similarly ineffective, although a small increase in CD25 expression could be detected when the B cells were cultured with phytohaemagglutinin A (PHA). The ability of IL-4 to promote CD25 expression was abolished by the presence of IFN-gamma in the culture. Titration experiments suggested that the amount of IL-4 required to produce a half-maximal increase in CD25 expression was approximately 40 U/ml; this is considerably greater than the 8-10 U/ml required to produce the equivalent effect on CD23 expression. The ability of IL-4 to promote CD25 expression in the high-density B-lymphocyte population was apparently independent of proliferation of the cells. IL-4 could not promote Tac expression on high-density T cells prepared from the same tissue source.
Butcher
R D
RD
Department of Biochemistry, University of Glasgow, U.K.
McGarvie
G M
GM
Cushley
W
W
D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D001685:Biological Factors / Q000494:pharmacology; D002469:Cell Separation / Q000379:methods; D002499:Centrifugation, Density Gradient; D016207:Cytokines; D004306:Dose-Response Relationship, Immunologic; D006801:Humans; D015847:Interleukin-4 / Q000276:immunology*; D009696:Nucleic Acids / Q000096:biosynthesis; D014066:Palatine Tonsil / Q000276:immunology*; D015375:Receptors, Interleukin-2 / Q000032:analysis*; D011994:Recombinant Proteins / Q000276:immunology / Q000494:pharmacology; D013601:T-Lymphocytes / Q000276:immunology
D001685:Biological Factors; D016207:Cytokines; D009696:Nucleic Acids; D015375:Receptors, Interleukin-2; D011994:Recombinant Proteins; D015847:Interleukin-4