Recent Advances in Host Immune Mechanisms Against Listeria monocytogenes Infection

Listeria monocytogenes (Lm) is a foodborne Gram-positive pathogenic bacterium that primarily causes clinical manifestations such as sepsis, meningitis, and monocytosis. The main susceptible populations include newborns, pregnant women, adults over 40 years old, and immunocompromised individuals. Currently, antibiotic therapy remains the primary clinical treatment, but in recent years the issue of antibiotic resistance has become increasingly prominent. This review summarizes recent advances in host immune mechanisms against Lm infection, focusing on: (1) the defensive roles of host barrier systems (intestinal, blood-brain, and placental barriers); (2) innate immune responses, including pathogen recognition via TLRs/NLRs signaling pathways, macrophage phagocytosis, and NK cell immune surveillance; and (3) adaptive immunity, particularly CD4⁺/CD8⁺ T cell-mediated specific immune responses and the long-term protective effects of memory T cells. By systematically elucidating the molecular mechanisms of these immune processes, this review aims to provide novel therapeutic strategies through enhancement of host immune functions for clinical management of Lm infection.