PMC

S055: Salmonella Enteritidis, S09: Salmonella Enteritidis, S203: Salmonella Enteritidis, S489: Salmonella Enteritidis, S009: Salmonella Typhimurium, S067: Salmonella Typhimurium, S357: Salmonella Typhimurium, S427: Salmonella Typhimurium, S023: Other Salmonella sp., S083: Other Salmonella sp., S231: Other Salmonella sp., S333: Other Salmonella sp.

A. Enumeration of Salmonella in the cecum of mice at 12 hours following oral infection with indicated Salmonella genotypes. Wild type and avrA⁻ Salmonella were counted following selective propagation on LB agar media plates containing 25μg/ml nalidixic acid, and avrA⁻/pAvrA was propagated on LB agar media plates containing 25μg/ml nalidixic acid, and ampicillin 100μg/ml, (n=5).
B. Enumeration of Salmonella in the peyer’s patch of mice at 6 h following oral infection with indicated Salmonella genotypes, using selective media as described in 3A, (n=5).
C. Enumeration of Salmonella in the mesenteric lymph node (MLN) of mice 12 h following oral infection with indicated Salmonella genotypes, using selective media as described in 3A, (n=5).
D. Enumeration of Salmonella in the spleen of mice at 24 h following oral infection with indicated Salmonella genotypes, using selective media as described in 3A, (n=5).
E. Body weight loss in mice infected with the indicated Salmonella genotypes, (n=15).
F. Mortality in mice infected with the indicated Salmonella genotypes, (n=5).
G. Spleen weight in mice infected with the indicated Salmonella genotypes for 7 days, (n=5).
H. Serum KC in mice infected with the indicated Salmonella genotypes, (n=5).

Lanes: 1, 1 kb ladder (Invitrogen); 2, Salmonella Typhimurium 81.23500; 3, Salmonella Enteritidis CVD SE; and 4, Salmonella Dublin 06-0707.

Salmonella (yellow) reside in intracellular vacuoles in infected host cells. Salmonella possesses internal (green) and surface-associated (red) antigens. Left) Live Salmonella shield internal antigens, but some of their surface-associated antigens are accessible for processing and presentation. As a consequence, T cells specific for Salmonella surface antigens can recognize these infected cells and initiate antibacterial immune effector mechanisms. In contrast, T cells specific for internal Salmonella antigens fail to detect host cells that contain exclusively intact Salmonella. Right) Dead Salmonella release internal antigens. As a consequence, both surface-exposed and internal antigens can be processed, presented, and recognized by cognate T cells. However, this recognition is unproductive for infection control since it targets Salmonella that are already dead.