Neutrophil granulocytes: new faces of old acquaintances

Abstract

Over the past few decades, thanks to the use of new technologies, the spectrum of functional capabilities of neutrophil granulocytes has been significantly expanded. Their effector potential with respect to infectious agents, including phagocytosis, the production of active forms of oxygen and nitrogen, degranulation with the release of numerous enzymes and antimicrobial peptides, and the formation of extracellular traps were studied in detail. However, it has been found that many of the factors that neutrophils use to directly destroy pathogens have a regulating effect on other cells of the immune system and the neutrophils themselves. In addition, upon activation, neutrophils are capable of synthesizing a number of de novo biologically active molecules. Traditionally considered as inducers of an inflammatory reaction, neutrophils demonstrate the ability to simultaneously incorporate mechanisms that contribute to limiting and resolving inflammation. Ambivalent both helper and suppressor effects of neutrophils on cells of congenital and adaptive immunity testifies to their important immunoregulatory role both in homeostasis and various types of pathology, particularly in the development of malignant tumors.