Inflammatory monocyte effector mechanisms.

Monocytes are blood-derived mononuclear phagocytic cells that traffic throughout the body and can provide rapid innate immune effector responses in response to microbial pathogen infections. Among blood monocytes, the most abundant subset in mice is represented by inflammatory Ly6C(+) CCR2(+) monocytes and is the functional equivalent of the CD14(+) monocytes in humans. Herein we focus on published evidence describing the exquisite functional plasticity of these cells, and we extend this overview to their multiples roles in vivo during host immune defenses against microbial pathogen infections, as antigen-presenting cells, inflammatory cells or Trojan horse cells.