Fig. 1: FcRn-mediated transport properties differ between the IgG1 Fc and full-length IgG1.

a, b Representative SPR sensorgrams of titrated amounts of monomeric FcRn injected over anti-NIP IgG1 and the IgG1 Fc fragment (~300 RU). c FcRn affinity chromatography and resulting elution profiles of anti-NIP IgG1 (shown in blue) and the IgG1 Fc fragment (shown in red). d Table summarizing key parameters from FcRn interaction studies shown in a–c. Elimination curves and estimated β-phase half-life of anti-NIP IgG1 and IgG1 Fc fragment in e homozygous Tg32 mice, f hemizygous Tg32 mice, and g mice lacking FcRn (FcRn KO). h Molar amounts in plasma at the start of the β-phase (1 day after IV injection) in the same mice and order as displayed in a–c. n = 5 individual mice for all six groups. i Illustration of the HERA methodology. j–l HERA parameters obtained for anti-NIP IgG1 and the IgG1 Fc fragment. Shown data represents two independent, representative experiments. HERA uptake following siRNA knockdown of FcRn and varying incubation time for the m anti-NIP IgG1 and n the IgG1 Fc fragment. Shown data represents two independent, representative experiments. o Illustration of transcytosis methodology used to obtain data on apical to basolateral FcRn-dependent transcytosis in MDCK cells stably overexpressing hFcRn shown in p. Shown data represent two independent experiments. IgG1 IHH denotes IgG1 with the amino acid substitutions I253A, H310A and H435A to abolish FcRn binding. *p < 0.05, **p < 0.005, ***p < 0.0005, ****p < 0.0001 (two-tailed, unpaired Student’s t test). Data in bar plots show mean values ± SD.