Protection against <i>S</i>. Typhimurium LT2 in mice by Mabs.

Survival (A) and relative percent survival (RPS) (B) Survival analyses of mice (n = 20 per group) infected intraperitoneally with 6.4×105 CFU of S. Typhimurium LT2, after 1 h, mice were injected intraperitoneally with either 300 or 500 μg/mouse of Mabs F1D4 or B7D4, while control mice received only PBS injection. Mice were monitored daily for morbidity and mortality over a period of 30 days. (C) Representative histopathology images (H&E, 200×, scale bar = 100 μm) of liver, spleen and cecum sections from mice challenged with 6.4×105 CFU of S. Typhimurium LT2 and treated intraperitoneal with F1D4, B7D4, or PBS on day 7 are presented in the first and second columns respectively. The liver sections exhibit focal necrotic areas accompanied by inflammatory cell infiltration (arrows). The spleen sections show multinucleated giant cells along with sparse lymphocytes (arrows) and the splenic medulla displays a disordered and chaotic appearance. In the cecum, there was a reduction in glandular goblet cells within the midgut mucosa, infiltration of a small number of lymphocytes in the lamina propria, and deformation (elliptical) of crypt structure. Damage was scored in the bottom right corner of each Fig, “+, ++, +++”indicate an increased severity successively.