S1P1 receptor agonism suppresses early pro-inflammatory cytokine/chemokine production and recruitment of activated innate immune cells during human pathogenic H1N1:2009 swine influenza virus infection. Mice were infected with 1 × 105 PFU A/Wisconsin/WSLH34939/09 influenza virus and either Vehicle (water), CYM5442 (2mg/kg) (1, 13, 25 and 37 hours-post-infection) or RP-002 (2mg/kg on 1 and 25 hours post-infection) were administered i.t. to mice. Pro-inflammatory cytokines and chemokines were measured 48 hours post-infection in BALF by ELISA in either CYM-5442 (A) or RP-002 treated mice (C). Total numbers of innate immune cells were quantified from collagenase digested lungs by flow cytometry at 48 hours post-influenza virus infection in mice treated with either CYM-5442 (B) or RP-002 (D). Data represent average ± SEM from 4–5 mice/group. *, p < 0.05; **, p < 0.005; ***, p < 0.0005. Results are representative of 2 independent experiments.