Human C5aR knock-in mice facilitate the production and assessment of anti-inflammatory monoclonal antibodies.
Complement component C5a binds C5a receptor (C5aR) and facilitates leukocyte chemotaxis and release of inflammatory mediators. We used neutrophils from human C5aR knock-in mice, in which the mouse C5aR coding region was replaced with that of human C5aR, to immunize wild-type mice and to generate high-affinity antagonist monoclonal antibodies (mAbs) to human C5aR. These mAbs blocked neutrophil migration to C5a in vitro and, at low doses, both prevented and reversed inflammatory arthritis in the murine K/BxN model. Of approximately 40 mAbs generated to C5aR, all potent inhibitors recognized a small region of the second extracellular loop that seems to be critical for regulation of receptor activity. Human C5aR knock-in mice not only facilitated production of high-affinity mAbs against an important human therapeutic target but were also useful in preclinical validation of the potency of these antagonists. This strategy should be applicable to other important mAb therapeutics.
Lee
Hyun
H
Immunology and Inflammation Department, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW 2010, Australia.
Zahra
David
D
Vogelzang
Alexis
A
Newton
Rebecca
R
Thatcher
Jenny
J
Quan
Annie
A
So
Trina
T
Zwirner
Jörg
J
Koentgen
Frank
F
Padkjaer
Søren B
SB
Mackay
Fabienne
F
Whitfeld
Peter L
PL
Mackay
Charles R
CR
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology*; D000939:Epitopes / Q000276:immunology; D006801:Humans; D007249:Inflammation / Q000188:drug therapy* / Q000276:immunology; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009504:Neutrophils / Q000276:immunology; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement / Q000235:genetics* / Q000378:metabolism
D000911:Antibodies, Monoclonal; C488033:C5AR1 protein, human; D000939:Epitopes; D008565:Membrane Proteins; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement