FIG 4.

Brucella melitensis infection reduces the capture of blood-borne bacteria by the spleen. Wild-type C57BL/6 mice were infected i.p. with a dose of 10⁵ CFU of B. melitensis and sacrificed at 18 days postinfection. Twenty minutes before sacrifice, mice were injected intravenously with 10⁸ CFU of live GFP-expressing Salmonella enterica serovar Typhimurium (GFP-Salmonella) bacteria, as indicated in Materials and Methods. (A and B) Localization by immunofluorescence of CD45R/B200⁺ B cells, GFP-Salmonella, and CD209⁺ MZMs or CD169⁺ MMMs in the spleens of naive (control) and infected mice. The panels are color coded with the text for the antigen examined. (C) The percentage of GFP-Salmonella-positive surface out of the total spleen surface for five spleens from control mice and mice at 18 days postinfection. This quantification was performed using the colocalization module of the AxioVision program (Zeiss). r.p., red pulp; w.p., white pulp. Significant differences between infected and control mice are marked with asterisks: **, P < 0.01. The data are representative of at least two independent experiments (n = 5).