However, when we compared the virulence of the F2365 ΔllsA and F2365 ΔllsB mutants to that of the F2365 WT strain, we discovered an unexpected difference between these two deletion mutants: llsB but not llsA (the gene coding for the toxin LLS) contributed to virulence in our mouse intravenous model of infection, indicating that LlsB performs additional functions apart from the putative posttranslational modification of LLS. This evidence concerns the gene SETD2 and infection.