Design of human interleukin-4 antagonists inhibiting interleukin-4-dependent and interleukin-13-dependent responses in T-cells and B-cells with high efficiency.
Human interleukin-4 possesses two distinct sites for receptor activation. A signalling site, comprising residues near the C-terminus on helix D, determines the efficacy of interleukin-4 signal transduction without affecting the binding to the interleukin-4 receptor alpha subunit. A complete antagonist and a series of low-efficacy agonist variants of human interleukin-4 could be generated by introducing combinations of two or three negatively charged aspartic acid residues in this site at positions 121, 124, and 125. One of the double variants, designated [R121D,Y124D]interleukin-4, with replacements of both Arg121 and Tyr124 by aspartic acid residues was completely inactive in all analysed cellular responses. The loss of efficacy in [R121D,Y124D]interleukin-4 is estimated to be larger than 2000-fold. Variant [R121D,Y124D]interleukin-4 was also a perfect antagonist for inhibition of interleukin-13-dependent responses in B-cells and the TF-1 cell line with a Ki value of approximately 100 pM. In addition, inhibition of both interleukin-4-induced and interleukin-13-induced responses could be obtained by monoclonal antibody X2/45 raised against interleukin-4Rex, the extracellular domain of the interleukin-4 receptor alpha subunit. These results indicate that efficient interleukin-4 antagonists can be designed on the basis of a sequential two-step activation model. In addition, the experiments indicate the functional participation of the interleukin-4 receptor alpha subunit in the interleukin-13 receptor system.
Medizinische Poliklinik, Universität, Würzburg, Germany.
H P
HP
Tony
B J
BJ
Shen
P
P
Reusch
W
W
Sebald
D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000276:immunology*; D015195:Drug Design; D006801:Humans; D018793:Interleukin-13 / Q000037:antagonists & inhibitors* / Q000276:immunology; D053661:Interleukin-13 Receptor alpha1 Subunit; D015847:Interleukin-4 / Q000037:antagonists & inhibitors* / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects; D016297:Mutagenesis, Site-Directed; D017455:Receptors, IgE / Q000378:metabolism; D018123:Receptors, Interleukin / Q000502:physiology; D053660:Receptors, Interleukin-13; D019948:Receptors, Interleukin-4; D013601:T-Lymphocytes / Q000276:immunology*
D000911:Antibodies, Monoclonal; C508181:IL13RA1 protein, human; D018793:Interleukin-13; D053661:Interleukin-13 Receptor alpha1 Subunit; D017455:Receptors, IgE; D018123:Receptors, Interleukin; D053660:Receptors, Interleukin-13; D019948:Receptors, Interleukin-4; D015847:Interleukin-4