Fig. 2: Engineering of human IgG1 antibodies for improved FcRn affinity at neutral pH leads to increased transcytosis in vitro.
From: Leveraging neonatal Fc receptor (FcRn) to enhance antibody transport across the blood brain barrier
A Table showing the 9 residue positions in the CH2 and CH3 regions that were substituted, either individually or as a combination of 2, 3 or 4 positions. B Affinities (KD) of the engineered variants to hFcRn at pH 6.0 and 7.4, as measured by SPR. C Schematic of the transcytosis assay: MDCK-II cells expressing hFcRn were cultured in a transwell plate. After addition of antibodies in the upper well, the plate was incubated for 24 h to allow transcytosis to the lower well, where antibodies are collected and their concentrations measured. D Transcytosis of all engineered Fc variants, normalized to WT hIgG1 Fc, compared to hFcRn affinity at pH 7.4. Transcytosis overall trended positively with affinity. Figure 2C was created in BioRender. Lafrance-Vanasse, J. (2025) https://BioRender.com/bc0teil.
