Monoclonal antibodies that recognize human granulocyte-macrophage colony-stimulating factor and neutralize its bioactivity in vitro.
We have produced monoclonal antibodies to bacterially synthesized, human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) and have studied in detail the characteristics of three strongly neutralizing antibodies. The antibodies reacted with GM-CSF at high dilution (EC50 = 0.1-1.7 nM) in an indirect ELISA but did not react with murine GM-CSF or other cytokines. They also recognized glycosylated hGM-CSF produced by human lymphocytes. The antibodies were able to immunoprecipitate rhGM-CSF, but only reacted weakly with rhGM-CSF on Western blots, indicating that they recognized a conformation-dependent epitope. Cross-blocking studies showed that the three antibodies recognized overlapping epitopes. The antibodies inhibited binding of 125I-labeled rhGM-CSF to HL-60 cells at nanomolar concentrations and neutralized GM-CSF activity in two different bioassays. These antibodies thus provide a useful tool for analyzing the specificity of bioassays and for further studies of the production and function of GM-CSF in vitro and in vivo.
Dempsey
P J
PJ
Melbourne Tumour Biology Branch, Ludwig Institute for Cancer Research, Australia.
Layton
J E
JE
Duhrsen
U
U
Nicola
N A
NA
Cebon
J
J
Burgess
A W
AW
Morstyn
G
G
D000818:Animals; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D001667:Binding, Competitive; D001853:Bone Marrow / Q000187:drug effects; D001854:Bone Marrow Cells; D000939:Epitopes; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000037:antagonists & inhibitors / Q000276:immunology* / Q000494:pharmacology; D006801:Humans; D006825:Hybridomas / Q000276:immunology; D066298:In Vitro Techniques; D051379:Mice; D009500:Neutralization Tests
D000911:Antibodies, Monoclonal; D000939:Epitopes; D016178:Granulocyte-Macrophage Colony-Stimulating Factor