Hello V H Krishna Prasad

Yes, monocytes do have phagocytic properties, but phagocytosis efficiency is regulated by cell differentiation.

Monocytes originate in the bone marrow and travel through the blood stream to peripheral tissues. They sense the environment and replenish the pool of tissue macrophages and DCs.

There are distinct populations of monocytes that can be identified based on CD14 and CD16 expression which includes CD14++ classical monocytes, CD14+CD16+ intermediate monocytes, and CD16++ nonclassical monocytes.

Classical monocytes, also called inflammatory monocytes, can infiltrate tissues, produce inflammatory cytokines, and differentiate into inflammatory macrophages. Classical monocytes also express several pattern recognition receptors (PRRs), which are proteins capable of recognizing molecules frequently found in pathogens and are involved in removing microorganisms and dying cells via phagocytosis.

In response to infection or injury, they proliferate in the bone marrow, are released into circulation in a CCR2-dependent manner and home to the site of interest via a chemokine gradient. For instance, during bacterial infection, these monocytes home to the site of infection and phagocytose pathogens, secrete a distinct set of chemokines that lead to recruitment of other immune cells, and present antigen via class II MHC.

Phagocytosis efficiency is regulated by cell differentiation. For instance, monocytes have a lower phagocytic capacity than neutrophils and macrophages but can enhance their phagocytic capacity upon cell differentiation. The capacity of monocytes to phagocytize diverse targets changes with their state of differentiation. IgG-opsonized particles are phagocytized better by mature macrophages than by undifferentiated monocytes. Similarly, the efficiency of complement-mediated phagocytosis depends on monocyte differentiation.

Best.

Thank you Malcolm Nobre