Fig. P1.

(A) (Left) Two-photon imaging of B cells that express membrane-bound ovalbumin (mOVA B), treated with either LPS or CpG, interacting with OTII T cells in the lymph node (LN). (Right) Formation of motile B–T pairs. TCR recognition of B-cell presentation of MHCII-OVA peptide and CTLA4 interaction with B7 molecules. (B) LPS-activated tolerogenic B cells physically out-compete nontolerogenic CpG-activated B cells, resulting in a partner swap. Competitive disruption of B–T contact occurs by directed migration of tolerogenic B cells, followed by a transient three-way B–T–B interaction and release of the nontolerogenic B cell.