Enhancement of host resistance against L. monocytogenes infection and cytokine production by administration of rmPGLYRP-1. C57BL/6 mice were injected with 100 μg of rmPGLYRP-1, heat-inactivated rmPGLYRP-1, or PBS, and titers of IFN-γ (A) and TNF-α (B) in the sera were determined 24 h after administration. Similarly, C57BL/6 mice were injected with 100 μg of rmPGLYRP-1, heat-inactivated rmPGLYRP-1, or PBS 6 h before infection with 5 × 106 CFU of L. monocytogenes, and viable bacterial numbers in the spleens (C) and livers (D) from mice were determined 1, 2, 3, and 5 days after infection. Titers of IFN-γ (E) and TNF-α (F) in the sera and spleens were determined for the rmPGLYRP-1-treated group, heat-inactivated rmPGLYRP-1-treated group, and PBS-treated group 24 h after infection. The threshold of detection is indicated by <12.5. Each group consists of six mice. Bars show SD. An asterisk indicates a significant difference from the PBS-treated group and heat-inactivated rmPGLYRP-1-treated group at P < 0.05.