Immune system refers to the collection of mechanisms involving cells, tissues and organs that protects organisms against disease by identifying and killing pathogens and tumour cells. Both these Neutrophils and Macrophages are phagocytes primarily involved in non-specific defence mechanism.
Similarities between Neutrophils and Macrophages
(i) Both are phagocytes
(ii) presence of common surface markers like chemokine receptors and receptors for Igs and complement and common patterns of cytokine and chemokine secretion
(iii) common expression of pattern recognition receptors (PRR)
(iv) cooperative participation in the orchestration of adaptive immune responses
(v) scavenger capacity
(vi) similarity on the kinetic behavior under inflammatory/infectious conditions. There are reports on the possible conversion of neutrophils into macrophages (Araki et al., 2004; Sasmono et al., 2007).
(vii) Ability for pinocytosis (the ingestion of liquid into a cell by the budding of small vesicles from the cell membrane).
Even though they show many similarities, macrophages and neutrophils are specialized cells with functional and function-related morphological distinctive features.