TABLE 1

Binding of humanized anti-TNFα antibodies to H-FcRn

WT
P257I/N434H
D376V/N434H
P257I/Q311I
KDa (nM) 37 ± 5 2.3 ± 0.2* 2.5 ± 1.4* 1.9 ± 0.4*
pH50b 6.6 ± 0.2 6.6 ± 0.1 6.5 ± 0.1 6.6 ± 0.1
% Bound pH 7.4c
13 ± 2
6 ± 2
6 ± 1
9 ± 2

  • ↵* P < 0.001 compared with WT.

  • ↵ a KD data determined from equilibrium analysis of two independent binding experiments and expressed as the mean ± S.D.

  • ↵ b pH at which 50% of the IgG/H-FcRn complexes dissociates as determined from a four-parameter nonlinear regression fit (described under Materials and Methods) of the ELISA data.

  • ↵ c Percentage of the total antibody in preformed complexes that remained FcRn-bound at pH 7.4 as determined by ELISA.