Innate Immunity against Intracellular Bacteria: Mechanisms and Strategies

Editorial

20 March 2024

Editorial: Innate immunity against intracellular bacteria: mechanisms and strategies

Jingfei Tian

Han Liu

Jingai Che

and

Lei Song

3,092 views

1 citations

Editors

Lei Song

First Affiliated Hospital of Jilin University

Xiaolu Xiong

Beijing Institute of Microbiology and Epidemiology

Dong Sun

Qilu Hospital, Shandong University

Yanan Ma

Memorial Sloan Kettering Cancer Center

Impact

trachomatis evades the pursuit of innate immune cells. Pro-inflammatory cytokines secreted by C. trachomatis-infected cervical epithelial cells attract innate immune cells to the site of infection. Chlamydia protease-like activating factor (CPAF), which targets the cleaved NE surface receptor formyl peptide receptor 2 (FPR2), blocks the formation of neutrophil extracellular traps (NETs) and inhibits downstream reactive oxygen species (ROS) production, which paralyzes murine polymorphonuclear neutrophil (PMNs) activation. Chlamydia-infected NE produces elevated levels of extracellular ATP, adenosine triphosphate (ATP) that binds to P2X purinocreceptor 7 (P2X7R) and activates the NLRP3 inflammasome, thereby contributing to macrophage-associated immunopathology. Chlamydia is released from epithelial cells by extrusion and then forms extrusions that are taken up by Mφ. Interferon-induced GTPases are known to promote inclusions ubiquitination, leading to premature inclusion lysis. Bacterial lipid antigens are presented to iNKT cells via CD1d molecules on the surface of Mφ and DC. Activated NKT and NK promote DC maturation through the release of IFN-γ and positive feedback from cell-to-cell interactions. Rab proteins involved in the DC endocytic cycle are recruited around the inclusions and impede MHC-I intracellular trafficking. Notably, MICA upregulation occurs in parallel with MHC class I downregulation, affecting the sensitivity of C. trachomatis-infected cells to NK cell activity.

Review

25 January 2024

Insights into innate immune cell evasion by Chlamydia trachomatis

Xinglv Wang

, 2 more and

Zhongyu Li

6,267 views

8 citations

Mtb infection of alveolar macrophages and DCs or monocytes have diverse outcome. In most individuals (Controllers) influenced by genetic and/or environmental factors, these cells kill the pathogen by poorly understood cell-autonomous mechanisms or being activated by a robust adaptive immune system to control the infection. In 5-10% cases, bacteria evade these mechanisms causing a dysregulated inflammatory response dominated by neutrophil functions, which cause immunopathology, damages the lung architecture, and generates a nutrient replete tissue microenvironment for the bacterium to multiply (Progressors). While the balance to recruit pathogen-controlling and pathogen permissive immune cells and appropriately prime adaptive immunity is critical for optimal protection, inflammatory pathways implicated in neutrophil recruitment and activation breaks the tolerance and exacerbates pathology leading to symptomatic TB disease.

Review

27 October 2023

Early innate cell interactions with Mycobacterium tuberculosis in protection and pathology of tuberculosis

Poornima Sankar

and

Bibhuti Bhusan Mishra

9,453 views

16 citations

FRAEM, fluorescence-reported allelic exchange mutagenesis. CRISPRi, CRISPR interference.

Mini Review

28 June 2023

Advances in genetic manipulation of Chlamydia trachomatis

Weiqiang Wan

, 2 more and

Jun Jiao

3,183 views

7 citations

Review

28 March 2023

Antimicrobial peptides´ immune modulation role in intracellular bacterial infection

Diana Ivonne Duarte-Mata

and

Mario César Salinas-Carmona

AMPs can modulate the host immune response in different ways. These include the regulation of the secretion of both anti- and proinflammatory cytokines and the expression of certain innate immune receptors. They can also increase the number of active macrophages and facilitate the phagolysosome formation. On the other hand, humoral immunity can also be modified.

Intracellular bacteria cause a wide range of diseases, and their intracellular lifestyle makes infections difficult to resolve. Furthermore, standard therapy antibiotics are often unable to eliminate the infection because they have poor cellular uptake and do not reach the concentrations needed to kill bacteria. In this context, antimicrobial peptides (AMPs) are a promising therapeutic approach. AMPs are short cationic peptides. They are essential components of the innate immune response and important candidates for therapy due to their bactericidal properties and ability to modulate host immune responses. AMPs control infections through their diverse immunomodulatory effects stimulating and/or boosting immune responses. This review focuses on AMPs described to treat intracellular bacterial infections and the known immune mechanisms they influence.

9,924 views

57 citations