Figure 1.

Binding of monomeric and dimeric IgA/IgG domain swap mutant antibodies to pIgR expressed on MDCK cells. (a) Staining of MDCK cells with sheep anti-pIgR (heavy line) antiserum or normal sheep serum (broken line) followed by anti-sheep IgG FITC conjugate. (b) Binding of wild-type IgA monomer (thin line) or dimer (heavy line) to pIgR on MDCK cells. (c) Binding of VGAA mutant expressed as monomer (thin line) or dimer (heavy line) to pIgR on MDCK cells. (d) Binding of VGGA mutant expressed as monomer (thin line) or dimer (heavy line) to pIgR on MDCK cells. Bound IgA or IgA/G chimeric antibodies were detected by rabbit anti–human κ chain-FITC conjugate. Negative controls are shown as broken lines.