Comparison of Listeria host resistance between C57BL/6J and C57BL/6N inbred strains. (A) Kaplan-Meier survival curves of females and males of the C57BL/6J and C57BL/6N strains after intravenous (IV)v. infection with 2 × 104 colony-forming units (cfu) of Listeria monocytogenes strain EGD. (B) Bacterial load in liver and spleen of C57BL/6J and C57BL/6N mice after IV infection with 2 × 104 cfu L. monocytogenes EGD. Organ loads were ascertained at four time points to analyze kinetics of bacterial growth. (C) Comparison of plasma levels of interleukin (IL)-6, interferon-inducible protein (IP)-10, and chemokine ligand (CCL)2 between the C57BL/6J and C57BL/6N mice shown in (B). Concentrations of pro-inflammatory cytokines and chemokines were determined in peripheral blood samples using the Cytokine Mouse 20-Plex Panel (Invitrogen Inc., Foster City, CA, USA) and a LiquiChip 100 system (Qiagen, Hilden, Germany). Significant differences are indicated as follows: *P < 0.05, **P < 0.01 Mann-Whitney, U-test. Black bars and symbols, C57BL/6J inbred strain. White bars and symbols, C57BL/6N inbred strain.