Proposed model for tolerance induction on memory anti-Gal B cells by α-gal epitopes. Anti-Gal BCR molecules engaging α-gal epitopes on autologous or syngeneic cells deliver a tolerizing signal to the anti-Gal B cell in the complete absence of T-cell help. If, however, helper T cells are activated, their help rescues the anti-Gal B cell from being tolerized and induces activation of the B cell.