Formation and Maturation of the Phagosome: A Key Mechanism in Innate Immunity against Intracellular Bacterial Infection

Abstract

Phagocytosis is an essential mechanism in innate immune defense, and in maintaining homeostasis to eliminate apoptotic cells or microbes, such as Mycobacterium tuberculosis, Salmonella enterica, Streptococcus pyogenes and Legionella pneumophila. After internalizing microbial pathogens via phagocytosis, phagosomes undergo a series of ‘maturation’ steps, to form an increasingly acidified compartment and subsequently fuse with the lysosome to develop into phagolysosomes and effectively eliminate the invading pathogens. Through this mechanism, phagocytes, including macrophages, neutrophils and dendritic cells, are involved in the processing of microbial pathogens and antigen presentation to T cells to initiate adaptive immune responses. Therefore, phagocytosis plays a role in the bridge between innate and adaptive immunity. However, intracellular bacteria have evolved diverse strategies to survive and replicate within hosts. In this review, we describe the sequential stages in the phagocytosis process. We also discuss the immune evasion strategies used by pathogens to regulate phagosome maturation during intracellular bacterial infection, and indicate that these might be used for the development of potential therapeutic strategies for infectious diseases.

Gold Nanoparticles and Graphene Oxide Flakes Synergistic Partaking in Cytosolic Bactericidal Augmentation: Role of ROS and NOX2 Activity

“…Following the ingestion of bacteria, acidification by phagosomes and the fusion of phagosomes and lysosomes are two main characteristics of phagocyte maturation [58]. Our results showed a significant increase in phagosomal acidification of the GNP-and GOF-pretreated BMDMs following the ingestion of S. aureus and E. coli, as compared with the control BMDMs (Figure 4).…”

Transcriptome analysis reveals immune‐related differentially expressed genes in the hepatopancreas and gills of Penaeus vannamei after Vibrio anguillarum infection

“…Kureishi et al (1997) research has demonstrated that Rho‐kinase directly modulates smooth muscle contraction through myosin light chain phosphorylation, independently of the Ca 2+ ‐calmodulin‐dependent myosin light chain kinase pathway. In multicellular organisms, phagocytosis plays a role in maintaining cellular homeostasis by removing dead cells, microbes and cellular or foreign debris (Lee et al, 2020; Lee et al, 2020). Bandola‐Simon and Roche's (2019) research has shown that MLC2 in hepatopancreas tissue may resist the infection of Vibrio anguillae by triggering actin rearrangement and forming phagosomes.…”

Recent advances in antibody‐based immunotherapy strategies for COVID‐19

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