An analysis of the cellular requirements for the production of soluble interleukin-2 receptors in vitro

• Published in: Journal of clinical immunology 1986-03, Vol.6 (2), p.114-120
• Main Authors: NELSON, D. L, RUBIN, L. A, KURMAN, C. C, FRITZ, M. E, BOUTIN, B
• Format: Article
• Language: English
• Subjects: Analysis of the immune response. Humoral and cellular immunity; B-Lymphocytes - immunology; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Immunobiology; In Vitro Techniques; Interleukin-2 - immunology; Leukocytes - immunology; Lymphocyte Activation; Lymphokines, interleukins ( function, expression); Monocytes - immunology; Receptors, Immunologic - biosynthesis; Receptors, Interleukin-2; Regulatory factors and their cellular receptors; Solubility; T-Lymphocytes - classification; T-Lymphocytes - immunology
• ISSN: 0271-9142; 1573-2592
• DOI: 10.1007/BF00918743

Following activation in vitro, peripheral blood mononuclear cells (PBMC) express cell-associated interleukin-2 receptors (IL-2R) and also release soluble IL-2R into culture supernatants. The present studies were undertaken to define which normal cells were responsible for the release of soluble IL-2R in vitro. Both cell-associated and soluble IL-2R were quantitatively measured with a "sandwich" enzyme-linked immunoassay employing two monoclonal antibodies. PBMC were separated into populations of surface immunoglobulin-negative cells (T cells and monocytes) and surface immunoglobulin-positive cells (B cells and monocytes), and the T-cell population was further separated into OKT4-positive (OKT4+) cells and OKT4-negative (OKT4-) cells. Following activation with phytohemagglutinin, pokeweed mitogen, and the monoclonal antibody OKT3, large amounts of soluble IL-2R were released by PBMC, unseparated T cells, OKT4+ T cells, and OKT4- T cells. The population containing B cells and monocytes made small but readily detectable amounts of soluble IL-2R when stimulated with these T-cell mitogens; likely the result of contaminating T cells in the population. However, when highly purified B cells were stimulated with Staphylococcus aureus Cowan and recombinant IL-2, they also released small amounts of soluble IL-2R. The release of soluble IL-2R by T cells appeared monocyte dependent when OKT3, but not phytohemagglutinin, was employed for activation, and monocytes themselves released no detectable IL-2R under the conditions employed. These studies define the cellular requirements for the release of soluble IL-2R in vitro and demonstrate that such receptors are released by B cells, T cells, and both OKT4+ and OKT4- T-cell subsets.