FIG 9.

NMII induction of B1a B cell death is dependent on bacterial replication and a functional T4SS. (A) Staining by TUNEL was measured in B1a B cells infected with NMII and treated with rifampin or mock infected by use of PBS. (B) The number of cells with positive DNA fragmentation by TUNEL was counted at day 1 and day 3 postinfection. (C) The MTS assay was used to measure cell viability following infection with NMII, heat-killed NMII, and dotA-deficient NMII. *, P < 0.05; ***, P < 0.001. These data indicate that NMII replication and a functional T4SS are required in order to induce B1a B cell death.