IL1B and plague: CO92ΔyopH infection presents a significantly different picture: 1) there is little bacterial replication in the lungs (Fig. 3), 2) CO92ΔyopH is severely attenuated in both bubonic and pneumonic plague models (Fig. 1A &1B and [18]), and 3) TNF-α and IL-1β are readily detectable in the BALF of mice infected with CO92ΔyopH at 24 hours post-infection (Fig. 4A &4B) suggesting that CO92ΔyopH induces a detectable inflammatory response in the lung.