Epitope analysis of human IL-6 receptor gp80 molecule with monoclonal antibodies.
Gp80 human IL-6R was studied using 7 murine mAb (M37, M91, M113, M139, M164, M182 and M195) obtained after fusion of splenocytes of Balb/c mice immunised with a mixture of recombinant IL-6 receptor (rIL-6R) and cells from 2 cell lines expressing IL-6R. These were U266, which is IL-6 independent and XG-1 which is IL-6-dependent. In ELISA the 7 mAb reacted against the rIL-6R and against the natural soluble form found in plasma (nIL-6R), which both lack transmembrane and cytoplasmic domains. However, M195 reacted less with the natural than with the recombinant soluble IL-6R. Using FACS analysis, the 7 mAb were shown to bind to U266 cells but not to the Namalva cell line which is deprived of IL-6R. This showed that they all recognised the membrane form of the IL-6R. Three of the anti-IL-6R mAb reacted with rIL-6R by Western blotting. Four different epitopes of the molecule were identified, either by cross-blocking experiments of mAb binding to IL6R in ELISA or by the biosensor Biacore technology. A group of 4 mAb (M37, M113, M139 and M164) and another mAb (M195) identified 2 different epitopes involved in IL-6 binding. These antibodies were able to inhibit the binding of IL-6 to IL-6R and the proliferation of the IL-6-dependent XG-1 cell line. M91 and M182 recognized 2 other epitopes that were not involved in IL-6 binding. As expected, M91 did not inhibit XG-1 proliferation; in contrast, M182 interfered with the proliferative response of the XG-1 cell line.(ABSTRACT TRUNCATED AT 250 WORDS)
Liautard
J
J
INSERM U291, Montpellier, France.
Gaillard
J P
JP
Mani
J C
JC
Montero-Julian
F
F
Duperray
C
C
Lu
Z Y
ZY
Jourdan
M
M
Klein
B
B
Brailly
H
H
Brochier
J
J
D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D000939:Epitopes; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000276:immunology*; D018123:Receptors, Interleukin / Q000737:chemistry*; D019947:Receptors, Interleukin-6; D011994:Recombinant Proteins / Q000737:chemistry
D000911:Antibodies, Monoclonal; D000939:Epitopes; C508603:IL6R protein, human; D015850:Interleukin-6; D008562:Membrane Glycoproteins; D018123:Receptors, Interleukin; D019947:Receptors, Interleukin-6; D011994:Recombinant Proteins