Subclinical Salmonella Infection in Mice

S. enterica serovar Typhimurium strain M525P (49 (link)), a strain of intermediate virulence, was used to establish subclinical infection in vivo. In particular, overnight (stationary phase) bacterial cultures were first washed and resuspended in Dulbecco's PBS (Sigma) and then diluted to the desired dose. WT and Lrrk2^−/− mice were subsequently challenged intravenously with 0.2 ml of the bacterial suspension. The exact dose, as determined by serial dilution and plating the inoculum on LB plates before and after infection, was 1.3 × 10⁴ cfu/mouse. Mice were bled and then euthanized at certain intervals after the initial challenge. Their spleens were aseptically removed and weighed. Mouse serum was analyzed via ELISA for levels of IL-18 (MBL International) and IFN-γ (DuoSet Development Kit, R&D Systems).