PSMB9 and infection: Thus, given sufficient time, LMP2/β1i and LMP7/β5i-deficient splenic APC processed rLM-E1-derived E1B in sufficient quantities to trigger specific CD8+ T-cells, but LMP2/β1i and LMP7/β5i-deficient mice failed to respond to this epitope (while responding to control epitopes) following primary infection.