FIG 2.

Attenuation and immunologic characterization of LMA vaccine in Rag1 KO mice. C57BL6 Rag1 KO mice were infected with 2.0 × 10⁶ CFU of LMA by either the i.n. or the i.m. route (n = 10 each route). (A) On day 5 p.i., 5 animals from each infection route were euthanized, and spleen, lungs, or muscle (depending on the infection route) was collected to quantify the number of LMA. (B) The survival of the remaining LMA infected animals (5 from each route) was monitored for up to 28 days p.i. After 28 days of LMA infection, all surviving mice (n = 10) were challenged with 6 LD₅₀ of CO92. (C) The mortality of animals was recorded, and bacterial loads in the lungs from 5 moribund animals (inset) were enumerated. F1-V-specific IgG titers were evaluated by ELISA from sera collected at day 3 post-CO92 challenge. Sera collected from uninfected naive Rag1 KO mice and conventional mice immunized with LMA (2.0 × 10⁶ CFU i.m.) served as negative and positive controls, respectively (D). One-way ANOVA was used to determine significance between groups for bacterial burdens and antibody titers. Kaplan-Meier analysis with log-rank (Mantel-Cox) test was used for analysis of animal survival. Asterisks represent the statistical significance between two groups, indicated by a line. ***, P < 0.001. Two biological replicates were performed and data plotted.