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He H, Zhang YL, Li Y, Huang Y, Li X, Xu J, Du YR. Efficacy and prognostic value of peripheral blood CD4 + T cells and serum IL-6 and IL-8 in tuberculous meningitis. Heliyon 2024; 10:e31641. [PMID: 38845916 PMCID: PMC11154195 DOI: 10.1016/j.heliyon.2024.e31641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 05/19/2024] [Accepted: 05/20/2024] [Indexed: 06/09/2024] Open
Abstract
Objective To investigate the value of peripheral blood clusters of differentiation 4 (CD4+) T-lymphocyte (T cells) count and serum interleukin-6 (IL-6) and interleukin-8 (IL-8) in the treatment and prognosis of tuberculous meningitis (TBM). Methods Sixty-five patients with TBM were prospectively included in the observation group. Sixty-five patients with pulmonary TB and a group of 65 healthy individuals served as the control groups. The differences in peripheral blood CD4+ T-cell count, serum IL-6, and IL-8 levels were compared, and changes in these indices after anti-TB treatment in the observation group were analysed. The observation group was divided into effective and ineffective groups based on their response after 24 weeks of anti-TB treatment. The study also evaluated the influence of peripheral blood CD4+ T-cell count, serum IL-6, and IL-8 levels on the adverse prognosis of TBM during anti-TB treatment. Results Before treatment, the CD4+ T-cell count in the peripheral blood of the observation group was lower than in both the control and healthy groups, and serum IL-6 and IL-8 levels were higher than in the control group (P < 0.001). After 24 weeks of anti-TB treatment, the CD4+ T-cell count in the peripheral blood of the observation group increased, whereas the levels of IL-6 and IL-8 decreased significantly (P < 0.001). The levels of CD4+ T cells and IL-6 in the peripheral blood of patients before treatment were identified as independent factors influencing the efficacy of anti-TB treatment (odds ratio [OR] = 0.989, 95 % confidence interval [CI]: 0.980-0.997; OR = 1.010, 95 % CI: 1.003-1.017). Conclusion In patients with TBM, the CD4+ T-cell count in the peripheral blood is decreased, whereas serum IL-6 and IL-8 are increased. The combination of CD4+ T cells and IL-8 shows a degree of predictive value for the prognosis of anti-TB treatment.
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Affiliation(s)
- Hua He
- Department 2 of Infectious Disease, The Third People's Hospital in Kunming/Yunnan Clinical Medical Center for Infectious Diseases, Kunming, 650041, China
| | - Yan-Ling Zhang
- Department 2 of Infectious Disease, The Third People's Hospital in Kunming/Yunnan Clinical Medical Center for Infectious Diseases, Kunming, 650041, China
| | - Yang Li
- Department 2 of Infectious Disease, The Third People's Hospital in Kunming/Yunnan Clinical Medical Center for Infectious Diseases, Kunming, 650041, China
| | - Ying Huang
- Department 2 of Infectious Disease, The Third People's Hospital in Kunming/Yunnan Clinical Medical Center for Infectious Diseases, Kunming, 650041, China
| | - Xiang Li
- Department of Radiology, The Third People's Hospital in Kunming/Yunnan Clinical Medical Center for Infectious Diseases, Kunming, 650041, China
| | - Jun Xu
- Department 2 of Infectious Disease, The Third People's Hospital in Kunming/Yunnan Clinical Medical Center for Infectious Diseases, Kunming, 650041, China
| | - Ying-Rong Du
- Department of Cardiovascular Medicine, The Third People's Hospital in Kunming/Yunnan Clinical Medical Center for Infectious Diseases, Kunming, 650041, China
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Li P, Wang R, Dong WQ, Wang GY, Zhang AD, Chen HC, Tan C. Systemic neutrophils are triggered by respiratory Bacillus Calmette- Guérin and mediate pulmonary mycobacterial clearance in synergy with the triggering receptor expressed on myeloid cells 1. Microb Pathog 2024; 187:106535. [PMID: 38176463 DOI: 10.1016/j.micpath.2024.106535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/26/2023] [Accepted: 01/02/2024] [Indexed: 01/06/2024]
Abstract
Tuberculosis remains a threat to public health. The only approved vaccine, Bacillus Calmette-Guérin (BCG), is administered intradermally and provides limited protection, and its effect on innate immunity via the respiratory route has not been fully elucidated. A mouse model with genetically depleted TREM1 and seven-color flow cytometry staining were used to characterize the comprehensive immune response induced by respiratory BCG, through evaluating organ bacterial loads, lung histopathology, and lung immunohistochemistry. During respiratory BCG infection, the murine lungs displayed effective bacterial clearance. Notably, marked differences in neutrophils were observed between thymus and bone marrow cells, characterized by a significant increase in the expression of the triggering receptor expressed on myeloid cells 1 (TREM1). Subsequently, upon depletion of TREM1, a reduction in pulmonary neutrophils was observed, which further exacerbated bacterial loads and resulted in worsened pathology following respiratory BCG infection. In summary, up-regulated expression of TREM1 in rapidly increasing circulating neutrophil by pulmonary BCG is required for an efficient host response to BCG infection, and suggests the important role of TREM1 in neutrophil-related pulmonary bacteria clearance and pathology.
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Affiliation(s)
- Pei Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China; Systematic Immunology of Tuberculosis, National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, Shenzhen, China
| | - Rui Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China; Department of Experimental Animal Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Wen-Qi Dong
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Gao-Yan Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - An-Ding Zhang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Huan-Chun Chen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Chen Tan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.
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3
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Alcantara CA, Glassman I, Nguyen KH, Parthasarathy A, Venketaraman V. Neutrophils in Mycobacterium tuberculosis. Vaccines (Basel) 2023; 11:vaccines11030631. [PMID: 36992214 DOI: 10.3390/vaccines11030631] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/07/2023] [Accepted: 03/09/2023] [Indexed: 03/16/2023] Open
Abstract
Mycobacterium tuberculosis (M. tb) continues to be a leading cause of mortality within developing countries. The BCG vaccine to promote immunity against M. tb is widely used in developing countries and only in specific circumstances within the United States. However, current the literature reports equivocal data on the efficacy of the BCG vaccine. Critical within their role in the innate immune response, neutrophils serve as one of the first responders to infectious pathogens such as M. tb. Neutrophils promote effective clearance of M. tb through processes such as phagocytosis and the secretion of destructive granules. During the adaptative immune response, neutrophils modulate communication with lymphocytes to promote a strong pro-inflammatory response and to mediate the containment M. tb through the production of granulomas. In this review, we aim to highlight and summarize the role of neutrophils during an M. tb infection. Furthermore, the authors emphasize the need for more studies to be conducted on effective vaccination against M. tb.
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Affiliation(s)
- Cheldon Ann Alcantara
- Department of Basic Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Ira Glassman
- Department of Basic Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Kevin H Nguyen
- Department of Basic Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
| | | | - Vishwanath Venketaraman
- Department of Basic Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
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4
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Larsen SE, Williams BD, Rais M, Coler RN, Baldwin SL. It Takes a Village: The Multifaceted Immune Response to Mycobacterium tuberculosis Infection and Vaccine-Induced Immunity. Front Immunol 2022; 13:840225. [PMID: 35359957 PMCID: PMC8960931 DOI: 10.3389/fimmu.2022.840225] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 02/08/2022] [Indexed: 11/18/2022] Open
Abstract
Despite co-evolving with humans for centuries and being intensely studied for decades, the immune correlates of protection against Mycobacterium tuberculosis (Mtb) have yet to be fully defined. This lapse in understanding is a major lag in the pipeline for evaluating and advancing efficacious vaccine candidates. While CD4+ T helper 1 (TH1) pro-inflammatory responses have a significant role in controlling Mtb infection, the historically narrow focus on this cell population may have eclipsed the characterization of other requisite arms of the immune system. Over the last decade, the tuberculosis (TB) research community has intentionally and intensely increased the breadth of investigation of other immune players. Here, we review mechanistic preclinical studies as well as clinical anecdotes that suggest the degree to which different cell types, such as NK cells, CD8+ T cells, γ δ T cells, and B cells, influence infection or disease prevention. Additionally, we categorically outline the observed role each major cell type plays in vaccine-induced immunity, including Mycobacterium bovis bacillus Calmette-Guérin (BCG). Novel vaccine candidates advancing through either the preclinical or clinical pipeline leverage different platforms (e.g., protein + adjuvant, vector-based, nucleic acid-based) to purposefully elicit complex immune responses, and we review those design rationales and results to date. The better we as a community understand the essential composition, magnitude, timing, and trafficking of immune responses against Mtb, the closer we are to reducing the severe disease burden and toll on human health inflicted by TB globally.
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Affiliation(s)
- Sasha E. Larsen
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle Children's Hospital, Seattle, WA, United States
| | - Brittany D. Williams
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle Children's Hospital, Seattle, WA, United States,Department of Global Health, University of Washington, Seattle, WA, United States
| | - Maham Rais
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle Children's Hospital, Seattle, WA, United States
| | - Rhea N. Coler
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle Children's Hospital, Seattle, WA, United States,Department of Global Health, University of Washington, Seattle, WA, United States,Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, United States
| | - Susan L. Baldwin
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle Children's Hospital, Seattle, WA, United States,*Correspondence: Susan L. Baldwin,
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5
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Safar HA, Mustafa AS, Amoudy HA, El-Hashim A. The Effect of Delivery Systems on the Induction of T Helper 1 Cell Response to an ESAT6-Like Protein Rv3619c and Identification of Its Immunodominant Peptides. Med Princ Pract 2022; 31:359-367. [PMID: 35584661 PMCID: PMC9485963 DOI: 10.1159/000525136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 05/12/2022] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE This study determined the effects of chemical adjuvants, incomplete Freund's adjuvant (IFA) and aluminum hydroxide (Alum), mycobacteria, and a DNA plasmid as delivery systems on the induction of protective Th1 (interferon-gamma (IFN-γ)) and nonprotective Th2 (IL-5) and Treg (IL-10) cytokine responses to Rv3619c and its peptides. Rv3619c is an immunodominant Mycobacterium tuberculosis-specific antigen and belongs to the early-secreted antigenic target of 6 kDa-family of proteins. Delivery systems are needed to deliver such antigens in animal models and induce protective immune responses. METHODS The rv3619c gene was amplified from the genomic DNA of M. tuberculosis and cloned into appropriate vectors for expression in Escherichia coli, Mycobacterium smegmatis, and eukaryotic cells. Spleen cells from mice immunized with rv3619c using different delivery systems were stimulated in vitro with synthetic peptides (P1 to P6) of Rv3619c, and secreted cytokines were estimated by ELISA. RESULTS The recombinant M. smegmatis and DNA plasmid induced the secretion of the protective cytokine IFN-γ in response to peptide-pool of Rv3619c and all the individual peptides, whereas rv3619c/IFA induced the secretion of IFN-γ in response to the peptide pool, and the peptides P5 and P6. However, the secretions of the nonprotective cytokines IL-5 and IL-10 were induced to none of the peptides with the delivery systems used. CONCLUSION Rv3619c is a major antigen of M. tuberculosis with multiple immunogenic epitopes; however, immune responses to individual epitopes can vary based on delivery systems used.
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Affiliation(s)
- Hussain A. Safar
- Department of Microbiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Abu Salim Mustafa
- Department of Microbiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
- *Abu Salim Mustafa,
| | - Hanady A. Amoudy
- Department of Microbiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Ahmed El-Hashim
- Department of Pharmacology & Therapeutics, Faculty of Pharmacy, Kuwait University, Kuwait City, Kuwait
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Preclinical Progress of Subunit and Live Attenuated Mycobacterium tuberculosis Vaccines: A Review following the First in Human Efficacy Trial. Pharmaceutics 2020; 12:pharmaceutics12090848. [PMID: 32899930 PMCID: PMC7559421 DOI: 10.3390/pharmaceutics12090848] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 09/02/2020] [Accepted: 09/03/2020] [Indexed: 12/24/2022] Open
Abstract
Tuberculosis (TB) is the global leading cause of death from an infectious agent with approximately 10 million new cases of TB and 1.45 million deaths in 2018. Bacille Calmette-Guérin (BCG) remains the only approved vaccine for Mycobacterium tuberculosis (M. tb, causative agent of TB), however clinical studies have shown BCG has variable effectiveness ranging from 0–80% in adults. With 1.7 billion people latently infected, it is becoming clear that vaccine regimens aimed at both post-exposure and pre-exposure to M. tb will be crucial to end the TB epidemic. The two main strategies to improve or replace BCG are subunit and live attenuated vaccines. However, following the failure of the MVA85A phase IIb trial in 2013, more varied and innovative approaches are being developed. These include recombinant BCG strains, genetically attenuated M. tb and naturally attenuated mycobacteria strains, novel methods of immunogenic antigen discovery including for hypervirulent M. tb strains, improved antigen recognition and delivery strategies, and broader selection of viral vectors. This article reviews preclinical vaccine work in the last 5 years with focus on those tested against M. tb challenge in relevant animal models.
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Junqueira-Kipnis AP, Trentini MM, Marques Neto LM, Kipnis A. Live Vaccines Have Different NK Cells and Neutrophils Requirements for the Development of a Protective Immune Response Against Tuberculosis. Front Immunol 2020; 11:741. [PMID: 32391021 PMCID: PMC7189015 DOI: 10.3389/fimmu.2020.00741] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 04/01/2020] [Indexed: 12/24/2022] Open
Abstract
It has been shown that neutrophils drive NK cells to activate DCs while NK cells regulate neutrophils survival. In response to mycobacteria, NK cells proliferate and produces IFN-γ, that appears to regulate the neutrophilic inflammatory responses to both M. tuberculosis infection and BCG vaccination. Although the role of neutrophils in the immune response to tuberculosis is a matter of debate, neutrophils were shown to be crucial to induce specific response against mc2-CMX vaccine. The objective of this study was to investigate the interplay between NK cells and neutrophils in regard to the development of a protective immune response against M. tuberculosis. Depletion of NK cells during vaccination did not alter the total number of neutrophils or DCs, but reduced the number of activated DCs, thus reducing the generation of Th1 specific immune responses and the protection conferred by mc2-CMX and BCG vaccines. However, only in mc2-CMX vaccination that neutrophil depletion interfered with the NK cell numbers and protection. In conclusion, it was shown that only when both NK and neutrophils were present, specific Th1 response and protection was achieved by mc2-CMX vaccine, while neutrophils although activated upon BCG vaccination were not necessary for the induced protection.
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Affiliation(s)
- Ana Paula Junqueira-Kipnis
- Laboratory of Immunopathology of Infectious Disease, Department of Biosciences and Technology, Tropical Institute of Pathology and Public Health, Federal University of Goiás, Goiânia, Brazil
| | - Monalisa Martins Trentini
- Laboratory of Immunopathology of Infectious Disease, Department of Biosciences and Technology, Tropical Institute of Pathology and Public Health, Federal University of Goiás, Goiânia, Brazil
| | - Lázaro Moreira Marques Neto
- Laboratory of Immunopathology of Infectious Disease, Department of Biosciences and Technology, Tropical Institute of Pathology and Public Health, Federal University of Goiás, Goiânia, Brazil
| | - André Kipnis
- Laboratory of Molecular Bacteriology, Department of Biosciences and Technology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, Brazil
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8
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Neto LMM, Zufelato N, de Sousa-Júnior AA, Trentini MM, da Costa AC, Bakuzis AF, Kipnis A, Junqueira-Kipnis AP. Specific T cell induction using iron oxide based nanoparticles as subunit vaccine adjuvant. Hum Vaccin Immunother 2018; 14:2786-2801. [PMID: 29913109 DOI: 10.1080/21645515.2018.1489192] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
Metal-based nanoparticles (NPs) stimulate innate immunity; however, they have never been demonstrated to be capable of aiding the generation of specific cellular immune responses. Therefore, our objective was to evaluate whether iron oxide-based NPs have adjuvant properties in generating cellular Th1, Th17 and TCD8 (Tc1) immune responses. For this purpose, a fusion protein (CMX) composed of Mycobacterium tuberculosis antigens was used as a subunit vaccine. Citrate-coated MnFe2O4 NPs were synthesized by co-precipitation and evaluated by transmission electron microscopy. The vaccine was formulated by homogenizing NPs with the recombinant protein, and protein corona formation was determined by dynamic light scattering and field-emission scanning electron microscopy. The vaccine was evaluated for the best immunization route and strategy using subcutaneous and intranasal routes with 21-day intervals between immunizations. When administered subcutaneously, the vaccine generated specific CD4+IFN-γ+ (Th1) and CD8+IFN-γ+ responses. Intranasal vaccination induced specific Th1, Th17 (CD4+IL-17+) and Tc1 responses, mainly in the lungs. Finally, a mixed vaccination strategy (2 subcutaneous injections followed by one intranasal vaccination) induced a Th1 (in the spleen and lungs) and splenic Tc1 response but was not capable of inducing a Th17 response in the lungs. This study shows for the first time a subunit vaccine with iron oxide based NPs as an adjuvant that generated cellular immune responses (Th1, Th17 and TCD8), thereby exhibiting good adjuvant qualities. Additionally, the immune response generated by the subcutaneous administration of the vaccine diminished the bacterial load of Mtb challenged animals, showing the potential for further improvement as a vaccine against tuberculosis.
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Affiliation(s)
| | - Nicholas Zufelato
- b Instituto de Física, Universidade Federal de Goiás (IF-UFG) , Brasil
| | | | - Monalisa Martins Trentini
- a Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás (IPTSP-UFG) , Brasil
| | - Adeliane Castro da Costa
- a Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás (IPTSP-UFG) , Brasil
| | | | - André Kipnis
- a Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás (IPTSP-UFG) , Brasil
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Khademi F, Derakhshan M, Yousefi-Avarvand A, Tafaghodi M, Soleimanpour S. Multi-stage subunit vaccines against Mycobacterium tuberculosis: an alternative to the BCG vaccine or a BCG-prime boost? Expert Rev Vaccines 2017; 17:31-44. [DOI: 10.1080/14760584.2018.1406309] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Farzad Khademi
- Department of Microbiology, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran
| | - Mohammad Derakhshan
- Antimicrobial Resistance Research Center, Bu-Ali Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Arshid Yousefi-Avarvand
- Antimicrobial Resistance Research Center, Bu-Ali Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohsen Tafaghodi
- Nanotechnology Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Saman Soleimanpour
- Antimicrobial Resistance Research Center, Bu-Ali Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran
- Reference Tuberculosis Laboratory, Mashhad University of Medical Sciences, Mashhad, Iran
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Warren E, Teskey G, Venketaraman V. Effector Mechanisms of Neutrophils within the Innate Immune System in Response to Mycobacterium tuberculosis Infection. J Clin Med 2017; 6:jcm6020015. [PMID: 28178208 PMCID: PMC5332919 DOI: 10.3390/jcm6020015] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 01/24/2017] [Accepted: 02/03/2017] [Indexed: 11/18/2022] Open
Abstract
Neutrophils have a significant yet controversial role in the innate immune response to Mycobacterium tuberculosis (M. tb) infection, which is not yet fully understood. In addition to neutrophils’ well-known effector mechanisms, they may also help control infection of M. tb through the formation of neutrophil extracellular traps (NETs), which are thought to further promote the killing of M. tb by resident alveolar macrophages. Cytokines such as IFN-γ have now been shown to serve an immunomodulatory role in neutrophil functioning in conjunction to its pro-inflammatory function. Additionally, the unique transcriptional changes of neutrophils may be used to differentiate between infection with M. tb and other bacterial and chronic rheumatological diseases such as Systemic Lupus Erythematosus. Adversely, during the innate immune response to M. tb, inappropriate phagocytosis of spent neutrophils can result in nonspecific damage to host cells due to necrotic lysis. Furthermore, some individuals have been shown to be more genetically susceptible to tuberculosis (TB) due to a “Trojan Horse” phenomenon whereby neutrophils block the ability of resident macrophages to kill M. tb. Despite these aforementioned negative consequences, through the scope of this review we will provide evidence to support the idea that neutrophils, while sometimes damaging, can also be an important component in warding off M. tb infection. This is exemplified in immunocompromised individuals, such as those with human immunodeficiency virus (HIV) infection or Type 2 diabetes mellitus. These individuals are at an increased risk of developing tuberculosis (TB) due to a diminished innate immune response associated with decreased levels of glutathione. Consequently, there has been a worldwide effort to limit and contain M. tb infection through the use of antibiotics and vaccinations. However, due to several significant limitations, the current bacille Calmette-Guerin vaccine (BCG, vaccine against TB) does not meet the criteria for universal utilization for all ages and populations across the globe. New research involving neutrophils has yielded a new vaccine called M. smegmatis-Ag85C-MPT51-HspX (mc2-CMX) that has been shown to elicit a humoral and cellular response against M. tb in mice that is superior to the BCG vaccine.
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Affiliation(s)
- Eric Warren
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309 East Second Street, Pomona, CA 91766-1854, USA.
| | - Garrett Teskey
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766-1854, USA.
| | - Vishwanath Venketaraman
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309 East Second Street, Pomona, CA 91766-1854, USA.
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766-1854, USA.
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