F2 and infection: The ACT-producing Bp PT− bacteria (AC+PT–) reached the mLNs at higher numbers than Bp WT (AC+PT+) already on day 3 of infection and persisted at numbers increased to ~4 x 103 CFUs in the mLNs on day 14 of infection, thus exceeding the Bp PT− CFU counts in the lungs (cf. Fig 1A).