FIG 1.
T cells protect against Pla-deficient Y. pestis. (A, C, and E) B cell-deficient μMT (μMT) mice were left unvaccinated (unvac) or were primed and boosted intranasally with D27-pLpxL. (B, D, and F) WT mice were immunized intranasally with CT adjuvant alone (CT) or CT mixed with YopE69−77 peptide (CT+YopE) or control OVA257–264 peptide (CT+OVA). Mice were then challenged intranasally with approximately 10 MLD strain CO92 (1 × 104 CFU; A and B), strain CO92 ΔPla (1 × 105 CFU; C and D), or strain CO92 Pla-D206A (1.5 × 104 CFU; E and F). In comparison with unimmunized mice, immunized mice exhibited significantly increased survival after Pla-deficient CO92 challenge. Data for all panels are representative of results from 2 independent experiments (ns, not significant).