FIG 1.

Primary peritoneal B cells take up NMII. Primary peritoneal B cells were harvested by lavage and purified using CD19 MACS beads. (A) Following infection with NMII, cells were stained with antibodies against CD19 and NMII and DNA was visualized with DAPI. (B) Following infection with NMII, cells were stained with antibodies against NMII and LAMP-1 and visualized by confocal microscopy. (C) Flow cytometry plots of NMII-infected B cells at day 3 postinfection. The value at top right indicates the percentage of stained cells. (D) Infection rates observed by IFA at 1 and 3 days postinfection. Two hundred cells per slide were counted. ***, P < 0.001. (E) Measurement of the com1 gene copy number in infected purified B cells by real-time PCR at day 1 and day 3 postinfection. *, P < 0.05. These data indicate that primary peritoneal B cells are infected by NMII and that the bacteria are taken up into LAMP-1-positive vacuoles. DPI, days postinfection.