TREM2 and hepatitis A virus infection: In order to investigate the induction of cytokines before the peak of LCMV-induced hepatitis, we quantified protein concentrations of chemokine (C-X-C motif) ligand 1 (CXCL1), interleukin 6 (IL-6) and interferon alpha (IFNα) in sera of WT and Trem2−/− mice by ELISA (Fig. S7).