A monoclonal antibody recognizing 68- to 75-kilodalton protein(s) associated with the human IL-1 receptor.
We produced an IgM mAb termed 4.9 against an EBV-containing lymphoblastoid cell line, termed 3B6. This mAb reacted with both various B and T cell lines such as HSB2 cells, with an NK-like cell line YT-C3 cells, and with human fibroblast MCR-5 cells. It also reacted with normal resting peripheral B lymphocytes, monocytes, and anti-CD2- or anti-CD3-activated T lymphocytes. The 4.9 mAb immunoprecipitated two bands estimated to be of Mr 68 and 75 kDa from iodinated 3B6 cells. The 4.9 mAb inhibited the proliferation of peripheral T lymphocytes induced either by anti-CD3 mAb or anti-CD2 mAb. The 4.9 mAb inhibited also the proliferation of murine thymocytes both in the presence of PHA and IL-1 and the proliferation of human fibroblasts in the presence of IL-1. Radiolabeled IL-1 binding on 3B6 cells revealed two types of IL-1 binding sites with high and low affinity for IL-1 (300 sites/cell with a Kd of 6 x 10(-11)M and 6000 sites/cell with a Kd of 3 x 10(-9)M). On both 3B6 and YT-C3 cells, mAb 4.9 inhibited specifically the binding of 125I-labeled rIL-1, alpha or beta, whereas the irrelevant IgM mAb did not. Conversely, rIL-1, alpha or beta, could inhibit specifically the binding of radioiodinated 4.9 mAb to 3B6 or YT-C3 cells, whereas rIL-2, rIFN, or the irrelevant IgM mAb were ineffective. 125I-4.9 mAb bound 3B6 cells with an association constant (Ka) of 2 x 10(8)/M and demonstrated 6000 binding sites/cell. We thus conclude that mAb 4.9 recognizes a protein complex (68 to 75 kDa) closely associated with the IL-1R.
Bensimon
C
C
Laboratoire d'Immuno-Biologie Cellulaire, UA1156 CNRS, Villejuif, France.
Wakasugi
H
H
Wakasugi
N
N
Jitsukawa
S
S
Tursz
T
T
D000328:Adult; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000302:isolation & purification / Q000502:physiology; D000937:Antigen-Antibody Reactions; D001666:Binding Sites, Antibody; D001667:Binding, Competitive; D002455:Cell Division; D002460:Cell Line; D005347:Fibroblasts / Q000166:cytology / Q000276:immunology; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism* / Q000494:pharmacology; D008213:Lymphocyte Activation; D008970:Molecular Weight; D011233:Precipitin Tests; D011971:Receptors, Immunologic / Q000276:immunology*; D017472:Receptors, Interleukin-1; D013601:T-Lymphocytes / Q000276:immunology
D000911:Antibodies, Monoclonal; D007375:Interleukin-1; D011971:Receptors, Immunologic; D017472:Receptors, Interleukin-1