Impact of methionine oxidation in human IgG1 Fc on serum half-life of monoclonal antibodies.
IgG monoclonal antibodies (mAbs) consist of two Fab fragments and one Fc fragment. The Fab fragments contain the variable regions and are responsible for drug specificity (via antigen binding); the Fc fragment contains constant regions and is responsible for effector functions (via interactions with Fcγ receptors) and extended serum half-life (via interaction with the neonatal Fc receptor, FcRn). There are two conserved methionine (Met) residues located in the FcRn binding site of the Fc fragment. It has been shown previously that oxidation of these two Met residues decreases the binding affinity to FcRn. We have further evaluated the impact of Met oxidation on serum half-lives of two humanized IgG1 mAbs in transgenic mice with human FcRn. Variable oxidation levels were obtained by several procedures: exposure to an oxidizing agent, accumulation during extended refrigerated storage, or chromatographic separation. Our results show that Met oxidation can result in a significant reduction of the serum circulation half-life and the magnitude of the change correlates well with the extent of Met oxidation and changes in FcRn binding affinities. The relatively low levels of Met oxidation accumulated during 3 years of refrigerated storage had minimal impact on FcRn binding and no detectable impact on the serum half-life.
Preclinical DMPK Department, Merck Research Laboratories, Merck Sharp and Dohme Corp., West Point, PA 19486, United States.
Weirong
W
Wang
Josef
J
Vlasak
Yunsong
Y
Li
Pavlo
P
Pristatsky
Yulin
Y
Fang
Tamara
T
Pittman
Jeanette
J
Roman
Yang
Y
Wang
Thomayant
T
Prueksaritanont
Roxana
R
Ionescu
D000818:Animals; D000911:Antibodies, Monoclonal / Q000097:blood*; D006207:Half-Life; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007074:Immunoglobulin G / Q000378:metabolism*; D007143:Immunoglobulin Heavy Chains / Q000737:chemistry / Q000378:metabolism; D013058:Mass Spectrometry; D008715:Methionine / Q000378:metabolism*; D051379:Mice; D010084:Oxidation-Reduction / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D011961:Receptors, Fc / Q000378:metabolism*; D020349:Surface Plasmon Resonance; D013997:Time Factors
D000911:Antibodies, Monoclonal; D015395:Histocompatibility Antigens Class I; D007074:Immunoglobulin G; D007143:Immunoglobulin Heavy Chains; D011961:Receptors, Fc; D008715:Methionine; D006861:Hydrogen Peroxide; C100688:Fc receptor, neonatal