Recombinant interleukin-4 promotes expression of the CD25 (Tac) antigen at the plasma membrane of high-density human tonsillar B lymphocytes

• Published in: Immunology 1990, Vol.69 (1), p.57-64
• Main Authors: BUTCHER, R. D. J, MCGARVIE, G. M, CUSHLEY, W
• Format: Article
• Language: English
• Subjects: Analysis of the immune response. Humoral and cellular immunity; B-Lymphocytes - immunology; B-Lymphocytes - metabolism; Biological and medical sciences; Biological Factors - pharmacology; Cell Separation - methods; Centrifugation, Density Gradient; Cytokines; Dose-Response Relationship, Immunologic; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Immunobiology; Interleukin-4 - immunology; Lymphokines, interleukins ( function, expression); Nucleic Acids - biosynthesis; Palatine Tonsil - immunology; Receptors, Interleukin-2 - analysis; Recombinant Proteins - immunology; Recombinant Proteins - pharmacology; Regulatory factors and their cellular receptors; T-Lymphocytes - immunology
• ISSN: 0019-2805; 1365-2567

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.