Expression of IL-1 receptors on human peripheral B cells.
The expression of IL-1R on human peripheral B cells was analyzed by the binding assay with 125I-labeled human rIL-1 alpha and by the flow cytofluorometry by the use of FITC-conjugated IL-1 alpha. The proliferation and the differentiation of B cells stimulated with Staphylococcus aureus Cowan I (SAC) in the presence of T cell-derived factors were dependent on IL-1. By the binding experiment with 125I-labeled IL-1 alpha, B cells expressed only few IL-1R without any stimulations. When they were stimulated with SAC, IL-1R on B cells began to increase by only 1 h, reached the maximum level at 6 h. The binding of 125I-labeled IL-1 alpha to B cells was inhibited by the addition of either cold IL-1 alpha or IL-1 beta suggesting that IL-1R on B cells reactive for IL-1 alpha and IL-1 beta were identical. By Scatchard plot analysis, the existence of two classes of IL-1R on B cells was found. A major class of IL-1R (320 molecules/cell) has a lower affinity (Kd = 3.8 x 10(-10) M) and a minor class of IL-1R (70 molecules/cell) has a higher affinity (Kd = 4.4 x 10(-12) M). When B cells were stimulated with SAC, both lower and higher affinity IL-1R were increased to 1960 molecules/cell and 300 molecules/cell, respectively. Furthermore, IL-1R on B cells were also detected with FITC-conjugated IL-1 alpha by a flow cytofluorometer. Only 3 to 5% of B cells expressed IL-1R without any stimulations. When B cells were stimulated with SAC, IL-1R-positive B cells were increased to 20%. The addition of anti-class II antibodies inhibited B cell proliferation and differentiation induced with SAC, IL-1, and T cell-derived factors. Anti-class II antibodies also inhibited the number of IL-1R on B cells. These results suggest that the expression of IL-1R was induced as the initial stage of B cell activation and that class II Ag play an important role for the expression of IL-1R on B cells.
Tanaka
Y
Y
First Department of Internal Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
Shirakawa
F
F
Oda
S
S
Eto
S
S
Yamashita
U
U
D000911:Antibodies, Monoclonal / Q000502:physiology; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D001667:Binding, Competitive; D002454:Cell Differentiation / Q000187:drug effects; D005434:Flow Cytometry; D016650:Fluorescein-5-isothiocyanate; D005452:Fluoresceins; D006681:HLA-D Antigens / Q000276:immunology; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism* / Q000494:pharmacology; D015847:Interleukin-4; D007378:Interleukins / Q000494:pharmacology; D007700:Kinetics; D008213:Lymphocyte Activation / Q000187:drug effects; D008934:Mitogens; D011971:Receptors, Immunologic / Q000378:metabolism*; D017472:Receptors, Interleukin-1; D013861:Thiocyanates
D000911:Antibodies, Monoclonal; D005452:Fluoresceins; D006681:HLA-D Antigens; D007375:Interleukin-1; D007378:Interleukins; D008934:Mitogens; D011971:Receptors, Immunologic; D017472:Receptors, Interleukin-1; D013861:Thiocyanates; D015847:Interleukin-4; D016650:Fluorescein-5-isothiocyanate