Identification of a direct interaction between the Fab domains of IgG antibodies and human FcRn upon IgG-FcRn complex formation

Chemical cross-linking coupled to mass spectrometry was used to study the interaction between IgG-type antibodies and the neonatal Fc receptor (FcRn). Different cross-linking chemistries were used, including disuccinimidyl suberate (DSS); a combination of pimelic dihydrazide (PDH) in combination with the zero-length cross-linking reagent, DMTMM; and the Xplex method using hexanediamine and N-hydroxybenzotriazole.