Characterization of potential antagonists of human interleukin 5 demonstrates their cross-reactivity with receptors for interleukin 3 and granulocyte-macrophage colony-stimulating factor.
The ligand-binding alpha-chain of the human interleukin 5 (IL-5) receptor was expressed in its soluble form, lacking the transmembrane and cytoplasmic domains, from recombinant baculovirus. The soluble receptor was used in a scintillation proximity assay to identify two chemical compounds that inhibit binding of human IL-5 to the soluble receptor alpha chain with IC50 of 8 microM and 11 microM. These compounds also inhibited the interaction of human IL-5 with its membrane-bound receptor, composed of the ligand-binding alpha chain and signal-transducing beta chain, and prevented signaling through the receptor. Analysis by surface plasmon resonance and matrix-assisted laser-desorption/ionization mass spectrometry showed that the identified compounds bound irreversibly to the receptor at a 1:1 (mol/mol) ratio, suggesting a covalent interaction with the alpha chain of the human IL-5 receptor. Both compounds also inhibited the interaction of the receptors for interleukin 3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF), which are involved in hematopoietic differentiation and activation of immune cells, thus eliminating them as potential therapeutic agents. The inhibition of the structurally closely related receptors for IL-5, IL-3 and GM-CSF by both compounds, while binding of interleukin-4 to its receptor was not affected, suggests that a similar reactive site exists in the ligand-binding domains of the receptors for IL-5, IL-3 and GM-CSF.
Wiekowski
M
M
Department of Immunology, Schering Plough Research Institute, Kenilworth, NJ 07033, USA.
Prosser
D
D
Taremi
S
S
Tsarbopoulos
A
A
Jenh
C H
CH
Chou
C C
CC
Lundell
D
D
Zavodny
P
P
Narula
S
S
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D015374:Biosensing Techniques; D002455:Cell Division / Q000187:drug effects; D003429:Cross Reactions; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006801:Humans; D007377:Interleukin-3 / Q000378:metabolism; D015848:Interleukin-5 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051379:Mice; D010636:Phenols / Q000494:pharmacology*; D010880:Piperidines / Q000494:pharmacology*; D018123:Receptors, Interleukin / Q000037:antagonists & inhibitors* / Q000378:metabolism; D016185:Receptors, Interleukin-3 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D019948:Receptors, Interleukin-4; D053649:Receptors, Interleukin-5; D011994:Recombinant Proteins / Q000378:metabolism; D012995:Solubility; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D018411:Spodoptera; D013844:Thiazoles / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
C107084:4-ethylamino-2-methylthiophenol; D015703:Antigens, CD; D007377:Interleukin-3; D015848:Interleukin-5; D010636:Phenols; D010880:Piperidines; D018123:Receptors, Interleukin; D016185:Receptors, Interleukin-3; D019948:Receptors, Interleukin-4; D053649:Receptors, Interleukin-5; D011994:Recombinant Proteins; C107085:SCH 42886; D013844:Thiazoles; D016178:Granulocyte-Macrophage Colony-Stimulating Factor