Independence of macrophage activation and expression of the alleles of the Ity (immunity to typhimurium) locus.

These studies demonstrate that alleles at the Ity locus do not affect T cell-dependent activation of macrophages by Corynebacterium parvum. Using a genetic analysis involving mice expressing various combinations of the Ityr, Itys, Lpsd, and Lpsn alleles we also show that the expression of the Ity alleles is not dependent on the ability of LPS to active macrophages. Since macrophage activation is though to be important in the killing of salmonella, these findings favor a mechanism of action of the Ity locus that does not involve bacterial killing.