Infection of WT C57BL/6 mice with S. Typhimurium increased expression of αDβ2 on peritoneal macrophages when analyzed by flow cytometry (Figure 1A; Figure S1 in Supplementary Material), indicating that this integrin is involved in the host response to Salmonella. Because myeloid leukocyte accumulation is a feature of S. Typhimurium infection (23, 24), we examined inflammatory cell numbers in WT and αD–/– mice subjected to i.p. challenge with this pathogen. Here, ITGAD is linked to infection.