Defective presentation of IgA-OVA is restored by BCR ligation.

IIA1.6 cells transfected with (A) FcαR + IIA ITAM γ chain or (B) FcαR + Y→F mutant γ chain were incubated with DO-11-10 T cells and increasing concentrations of IgA-complexed NIP-OVA (NIP-OVA) with (indicated by cross-hatched bars) or without (indicated by black bars) ligation of BCR with 10 μg/mL anti-mIgG. IL-2 secretion by the T cells, a measure of antigen presentation, was assayed as described in “Materials and methods.” Similar results were obtained in 3 separate experiments.