Endocytosis of multimeric IgA by FcαR/γ-chain transfectants is not diminished in cells with altered γ chain.

IIA1.6 cells expressing FcαR and either WT γ chain (indicated by black bars), γ chain with IIA ITAM (indicated by cross-hatched bars), or γ chain with Y → F mutation (indicated by gray bars) were incubated with a polymeric human myeloma IgA at 4°C. After 1.5 hours, aliquots were removed, washed, and incubated at 37°C for the time period indicated. All cells were then washed and stained to detect surface-bound IgA. The results are expressed as the percentage of MFI of samples held at 4°C for 2 hours. The results are shown as the mean and SD of triplicate experiments.