Hierarchy of strength of protection against lethal systemic <i>F. tularensis</i> LVS challenge after vaccination of mice with LVS or the variants LVS-G, LVS-R, and heat-killed LVS.

<p>C57BL/6J mice were immunized by ID infection with 1×10⁴ CFU LVS, 1×10⁸ HK-LVS, 1×10⁴ LVS-G, or 1×10⁴ LVS-R. At 6 weeks after vaccination, mice vaccinated with PBS were challenged with 10³ or 10⁴ LVS IP; mice vaccinated with HK-LVS were challenged with 10³, 10⁴, or10⁵ LVS IP; and mice vaccinated with LVS, LVS-G, and LVS-R were challenged with 5×10⁴, 10⁵, 5×10⁵, or 10⁶ LVS IP, as indicated for each group, and monitored for survival. Results shown are from one representative experiment of three independent experiments of similar design with similar outcome.