title: A potent human anti-eotaxin1 antibody, CAT-213: isolation by phage display and in vitro and in vivo efficacy.
abstract: The CC chemokine, eotaxin1 (CCL11) is an important regulator of eosinophil function. A marked accumulation of eosinophils in tissues has been correlated with the up-regulation of eotaxin1 expression in several diseases. The potential therapeutic value of neutralizing the effects of eotaxin1 in inflammatory conditions (including asthma) is under investigation. A human single-chain fragment variable antibody that neutralizes human eotaxin1 (CAT-212) was produced using antibody phage display and converted to whole antibody IgG4 format (CAT-213). A novel approach to lead optimization in which the length of the variable heavy chain complementarity-determining region 3 was reduced by one amino acid resulted in an increase in potency of >1000-fold compared with the parent anti-eotaxin1 antibody. The optimized antibody binds eotaxin1 with high affinity (80.4 pM) and specificity. CAT-213 and CAT-212 do not bind or neutralize a range of other human proteins including human monocyte chemoattractant protein-1, a structurally similar chemokine. CAT-213 neutralizes the ability of eotaxin1 to cause an increase in intracellular calcium signaling (with an IC(50) value of 2.86 nM), migration of CCR3-expressing L1.2 cells (with an IC(50) value of 0.48 nM), and inhibition of the eotaxin1-evoked shape change of human eosinophils in vitro (with an IC(50) of 0.71 nM). Local administration of CAT-213 to mice (1-100 microg kg(-1)) attenuates dermal eosinophilia induced by human eotaxin1, achieving >90% inhibition of eosinophil influx. CAT-213 may therefore be of therapeutic value in inhibiting diseases in which eotaxin1 and eosinophils play a major role, for example, severe asthma.
authors.affiliation: Cambridge Antibody Technology, Granta Park CB1 6GH, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Main
authors.forename: Rachel
authors.initials: R
authors.lastname: Handy
authors.forename: Jane
authors.initials: J
authors.lastname: Wilton
authors.forename: Stephen
authors.initials: S
authors.lastname: Smith
authors.forename: Liz
authors.initials: L
authors.lastname: Williams
authors.forename: Leila Du
authors.initials: LD
authors.lastname: Fou
authors.forename: John
authors.initials: J
authors.lastname: Andrews
authors.forename: Louise A
authors.initials: LA
authors.lastname: Conroy
authors.forename: Richard
authors.initials: R
authors.lastname: May
authors.forename: Ian
authors.initials: I
authors.lastname: Anderson
authors.forename: Tristan J
authors.initials: TJ
authors.lastname: Vaughan
mesh_terms: D000465:Algorithms; D000595:Amino Acid Sequence; D019138:Antibodies, Blocking / Q000302:isolation & purification* / Q000494:pharmacology*; D020013:Calcium Signaling / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D054413:Chemokine CCL11; D019742:Chemokines, CC / Q000037:antagonists & inhibitors*; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D003001:Cloning, Molecular; D004618:Embolism, Air / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D004804:Eosinophils / Q000187:drug effects / Q000648:ultrastructure; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D009500:Neutralization Tests; D019151:Peptide Library
chemical_list: D019138:Antibodies, Blocking; C515456:CCL11 protein, human; D054413:Chemokine CCL11; D019742:Chemokines, CC; D007074:Immunoglobulin G; D019151:Peptide Library