Different Faces for Different Places: Heterogeneity of Neutrophil Phenotype and Function

Abstract

As the most abundant leukocytes in the circulation, neutrophils are committed to innate and adaptive immune effector function to protect the human body. They are capable of killing intruding microbes through various ways including phagocytosis, release of granules, and formation of extracellular traps. Recent research has revealed that neutrophils are heterogeneous in phenotype and function and can display outstanding plasticity in both homeostatic and disease states. The great flexibility and elasticity arm neutrophils with important regulatory and controlling functions in various disease states such as autoimmunity and inflammation as well as cancer. Hence, this review will focus on recent literature describing neutrophils' variable and diverse phenotypes and functions in different contexts.

Figure 1

Heterogeneity of neutrophils in both health and disease. Neutrophils protect human body from intruding microbes and they display notable heterogeneity in blood circulation and specific tissues. After being activated by pathogens, neutrophils extravasate from the blood vessel and function as “immune soldiers” in various states. Intriguingly, neutrophils are verified to share multiple phenotypes and functions in autoimmune disease and cancer as well as inflammation and infection.