Human recombinant dimeric IL-6 binds to its receptor as detected by anti-IL-6 monoclonal antibodies.
Three different epitopes of the human IL-6 (IL-6) molecule were recognized by the mAb B-E4 (IgG2b), B-E8 (IgG1) and B-F6 (IgG1). The affinities of these three mAb for IL-6 differ little in several assays but if ranked by affinity they fall into the following order B-E8 greater than B-E4 greater than B-F6. B-E4 and B-E8 mAb, recognizing two different epitopes, are inhibiting mAb in the bioassay with the IL-6 depending cell line B9, however B-E8 has an inhibiting activity higher than B-E4. Both human natural IL-6 (HnIL-6) and human recombinant IL-6 (HrIL-6) were inhibited but not the murine natural IL-6 (MnIL-6). Surprisingly, not only the non-inhibiting mAb (B-F6) recognizes the HrIL-6 fixed to the receptor but also the inhibiting mAb B-E4 and B-E8. This together with the results obtained in a sandwich ELISA where the same mAb was used as both catcher and tracer to detect HrIL-6, it was concluded that dimeric HrIL-6 is able to fix the IL-6 receptor. Competition studies between monomeric HnIL-6 and dimeric HrIL-6 showed that the affinity of the dimeric HrIL-6 for the receptor was higher than that of HnIL-6.
Wijdenes
J
J
CRTS, Laboratoire des Anticorps monoclonaux, Besancon, France.
Clement
C
C
Klein
B
B
Morel-Fourrier
B
B
Vita
N
N
Ferrara
P
P
Peters
A
A
D000818:Animals; D000911:Antibodies, Monoclonal; D000937:Antigen-Antibody Reactions; D001667:Binding, Competitive; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology; D006801:Humans; D006825:Hybridomas; D015850:Interleukin-6 / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D011971:Receptors, Immunologic / Q000378:metabolism*; D019947:Receptors, Interleukin-6; D011994:Recombinant Proteins / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D000939:Epitopes; D015850:Interleukin-6; D011971:Receptors, Immunologic; D019947:Receptors, Interleukin-6; D011994:Recombinant Proteins