Fig. 6.

Thy1⁺ NK cells are required for optimal vaccine-mediated protection. (A) B6 mice were orally infected with 5 × 10⁹ cfu BRD509, Δedd ΔpfkA ΔpfkB Salmonella, or left uninfected. Twelve weeks later, mice were orally infected with 1 × 10⁷ cfu WT Salmonella SL1344. Survival was assessed over 120 d. (B–D) Mice were vaccinated or left uninfected as in A. Two days before challenge with WT Salmonella SL1344, mice were treated i.p. with PBS or antibodies against mouse CD8 (2.43) and CD4 (GK1.5), NK1.1 (PK136), or Thy1 (30-H12). Antibody treatment was maintained twice weekly for the duration of the experiment. Survival was assessed over 15 d. Data are representative of two independent experiments with 9–16 mice per group. Statistical analyses: log-rank (Mantel-Cox) test. *P < 0.05.