Neutrophils.

The interaction with the pathogen can be direct, through recognition of pathogen-associated molecular patterns (PAMPs) by neutrophil pattern recognition receptors (PRRs), or indirect, through recognition of opsonised microbes by Fc receptors or complement receptors. The phagosome undergoes a rapid maturation process that involves the fusion with neutrophil granules and the targeted delivery of antimicrobial molecules and generation of reactive oxygen species (ROS). Figure 1. Left: Giemsa-stained human neutrophils as seen under the microscope; either freshly isolated (top) or cultured together with cytokines (bottom). Right: Human neutrophils harbouring phagocytosed mycobacteria as analysed by fluorescence microscopy.