1
|
Host–Pathogen Interactions of Marine Gram-Positive Bacteria. BIOLOGY 2022; 11:biology11091316. [PMID: 36138795 PMCID: PMC9495620 DOI: 10.3390/biology11091316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/30/2022] [Accepted: 09/01/2022] [Indexed: 11/17/2022]
Abstract
Simple Summary Complex interactions between marine Gram-positive pathogens and fish hosts in the marine environment can result in diseases of economically important finfish, which cause economic losses in the aquaculture industry. Understanding how these pathogens interact with the fish host and generate disease will contribute to efficient prophylactic measures and treatments. To our knowledge, there are no systematic reviews on marine Gram-positive pathogens. Therefore, here we reviewed the host–pathogen interactions of marine Gram-positive pathogens from the pathogen-centric and host-centric points of view. Abstract Marine Gram-positive bacterial pathogens, including Renibacterium salmoninarum, Mycobacterium marinum, Nocardia seriolae, Lactococcus garvieae, and Streptococcus spp. cause economic losses in marine fish aquaculture worldwide. Comprehensive information on these pathogens and their dynamic interactions with their respective fish–host systems are critical to developing effective prophylactic measures and treatments. While much is known about bacterial virulence and fish immune response, it is necessary to synthesize the knowledge in terms of host–pathogen interactions as a centerpiece to establish a crucial connection between the intricate details of marine Gram-positive pathogens and their fish hosts. Therefore, this review provides a holistic view and discusses the different stages of the host–pathogen interactions of marine Gram-positive pathogens. Gram-positive pathogens can invade fish tissues, evade the fish defenses, proliferate in the host system, and modulate the fish immune response. Marine Gram-positive pathogens have a unique set of virulence factors that facilitate adhesion (e.g., adhesins, hemagglutination activity, sortase, and capsules), invasion (e.g., toxins, hemolysins/cytolysins, the type VII secretion system, and immune-suppressive proteins), evasion (e.g., free radical quenching, actin-based motility, and the inhibition of phagolysosomal fusion), and proliferation and survival (e.g., heme utilization and siderophore-mediated iron acquisition systems) in the fish host. After infection, the fish host initiates specific innate and adaptive immune responses according to the extracellular or intracellular mechanism of infection. Although efforts have continued to be made in understanding the complex interplay at the host–pathogen interface, integrated omics-based investigations targeting host–pathogen–marine environment interactions hold promise for future research.
Collapse
|
2
|
Liang YC, Berton S, Reeks C, Sun J. An in vivo biosafety-level-2-compatible model of Mycobacterium tuberculosis infection for drug susceptibility testing. STAR Protoc 2022; 3:101575. [PMID: 35880128 PMCID: PMC9307682 DOI: 10.1016/j.xpro.2022.101575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Available mouse models for tuberculosis drug susceptibility testing requires using virulent biosafety-level-3 (BSL-3) Mycobacterium tuberculosis (Mtb) strains, or attenuated BSL-2 strains that lack virulence genes. Here, we present a BSL-2-compatible mouse model for tuberculosis drug susceptibility testing using the auxotrophic Mtb mc26206 strain, which retains all virulence genes. Using rifampicin and a new autophagy-boosting compound, SMIP-30, we provide a step-by-step guide for the infection, drug administration, and evaluation of Mtb burden and cytokine profiles. This protocol is easily adaptable for testing of other antibiotics and host-directed compounds. For complete details on the use and execution of this protocol, please refer to Berton et al. (2022). BSL-2 murine model of drug susceptibility testing against Mycobacterium tuberculosis Auxotrophic strain of Mycobacterium tuberculosis retaining all virulence genes Parallel measurement of bacterial burden and cytokine profiling in infected mice Easily adaptable to test combinations of antibiotics and host-directed compounds
Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.
Collapse
|
3
|
Negi K, Bhaskar A, Dwivedi VP. Progressive Host-Directed Strategies to Potentiate BCG Vaccination Against Tuberculosis. Front Immunol 2022; 13:944183. [PMID: 35967410 PMCID: PMC9365942 DOI: 10.3389/fimmu.2022.944183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 06/21/2022] [Indexed: 11/13/2022] Open
Abstract
The pursuit to improve the TB control program comprising one approved vaccine, M. bovis Bacille Calmette-Guerin (BCG) has directed researchers to explore progressive approaches to halt the eternal TB pandemic. Mycobacterium tuberculosis (M.tb) was first identified as the causative agent of TB in 1882 by Dr. Robert Koch. However, TB has plagued living beings since ancient times and continues to endure as an eternal scourge ravaging even with existing chemoprophylaxis and preventive therapy. We have scientifically come a long way since then, but despite accessibility to the standard antimycobacterial antibiotics and prophylactic vaccine, almost one-fourth of humankind is infected latently with M.tb. Existing therapeutics fail to control TB, due to the upsurge of drug-resistant strains and increasing incidents of co-infections in immune-compromised individuals. Unresponsiveness to established antibiotics leaves patients with no therapeutic possibilities. Hence the search for an efficacious TB immunization strategy is a global health priority. Researchers are paving the course for efficient vaccination strategies with the radically advanced operation of core principles of protective immune responses against M.tb. In this review; we have reassessed the progression of the TB vaccination program comprising BCG immunization in children and potential stratagems to reinforce BCG-induced protection in adults.
Collapse
|
4
|
Haddad A, Voth B, Brooks J, Swang M, Carryl H, Algarzae N, Taylor S, Parker C, Van Rompay KKA, De Paris K, Burke MW. Reduced neuronal population in the dorsolateral prefrontal cortex in infant macaques infected with simian immunodeficiency virus (SIV). J Neurovirol 2021; 27:923-935. [PMID: 34554407 PMCID: PMC8901521 DOI: 10.1007/s13365-021-01019-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 08/11/2021] [Accepted: 08/26/2021] [Indexed: 11/29/2022]
Abstract
Pediatric HIV infection remains a global health crisis with an estimated 150,000 new mother-to-child (MTCT) infections each year. Antiretroviral therapy (ART) has improved childhood survival, but only an estimated 53% of children worldwide have access to treatment. Adding to the health crisis is the neurological impact of HIV on the developing brain, in particular cognitive and executive function, which persists even when ART is available. Imaging studies suggest structural, connectivity, and functional alterations in perinatally HIV-infected youth. However, the paucity of histological data limits our ability to identify specific cortical regions that may underlie the clinical manifestations. Utilizing the pediatric simian immunodeficiency virus (SIV) infection model in infant macaques, we have previously shown that early-life SIV infection depletes the neuronal population in the hippocampus. Here, we expand on these previous studies to investigate the dorsolateral prefrontal cortex (dlPFC). A total of 11 ART-naïve infant rhesus macaques (Macaca mulatta) from previous studies were retrospectively analyzed. Infant macaques were either intravenously (IV) inoculated with highly virulent SIVmac251 at ~1 week of age and monitored for 6-10 weeks or orally challenged with SIVmac251 from week 9 of age onwards with a monitoring period of 10-23 weeks post-infection (19-34 weeks of age), and SIV-uninfected controls were euthanized at 16-17 weeks of age. Both SIV-infected groups show a significant loss of neurons along with evidence of ongoing neuronal death. Oral- and IV-infected animals showed a similar neuronal loss which was negatively correlated to chronic viremia levels as assessed by an area under the curve (AUC) analysis. The loss of dlPFC neurons may contribute to the rapid neurocognitive decline associated with pediatric HIV infection.
Collapse
Affiliation(s)
- Alexandra Haddad
- Department of Physiology and Biophysics, Howard University, Washington, DC, 20059, USA
| | - Brittany Voth
- Department of Physiology and Biophysics, Howard University, Washington, DC, 20059, USA
| | - Janiya Brooks
- Department of Physiology and Biophysics, Howard University, Washington, DC, 20059, USA
| | - Melanie Swang
- Department of Physiology and Biophysics, Howard University, Washington, DC, 20059, USA
| | - Heather Carryl
- Department of Physiology and Biophysics, Howard University, Washington, DC, 20059, USA
| | - Norah Algarzae
- Department of Physiology and Biophysics, Howard University, Washington, DC, 20059, USA
- King Saudi University, Riyadh, Riyadh, Kingdom of Saudi Arabia
| | - Shane Taylor
- Department of Physiology and Biophysics, Howard University, Washington, DC, 20059, USA
| | - Camryn Parker
- Department of Physiology and Biophysics, Howard University, Washington, DC, 20059, USA
| | - Koen K A Van Rompay
- California National Primate Research Center, University of California Davis, Davis, CA, 95616, USA
| | - Kristina De Paris
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Mark W Burke
- Department of Physiology and Biophysics, Howard University, Washington, DC, 20059, USA.
| |
Collapse
|
5
|
Sharan R, Kaushal D. Vaccine strategies for the Mtb/HIV copandemic. NPJ Vaccines 2020; 5:95. [PMID: 33083030 PMCID: PMC7555484 DOI: 10.1038/s41541-020-00245-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 09/15/2020] [Indexed: 02/06/2023] Open
Abstract
One-third of world’s population is predicted to be infected with tuberculosis (TB). The resurgence of this deadly disease has been inflamed by comorbidity with human immunodeficiency virus (HIV). The risk of TB in people living with HIV (PLWH) is 15–22 times higher than people without HIV. Development of a single vaccine to combat both diseases is an ardent but tenable ambition. Studies have focused on the induction of specific humoral and cellular immune responses against HIV-1 following recombinant BCG (rBCG) expressing HIV-1 antigens. Recent advances in the TB vaccines led to the development of promising candidates such as MTBVAC, the BCG revaccination approach, H4:IC31, H56:IC31, M72/AS01 and more recently, intravenous (IV) BCG. Modification of these vaccine candidates against TB/HIV coinfection could reveal key correlates of protection in a representative animal model. This review discusses the (i) potential TB vaccine candidates that can be exploited for use as a dual vaccine against TB/HIV copandemic (ii) progress made in the realm of TB/HIV dual vaccine candidates in small animal model, NHP model, and human clinical trials (iii) the failures and promising targets for a successful vaccine strategy while delineating the correlates of vaccine-induced protection.
Collapse
Affiliation(s)
- Riti Sharan
- Southwest National Primate Center, Texas Biomedical Research Institute, San Antonio, TX 78227 USA
| | - Deepak Kaushal
- Southwest National Primate Center, Texas Biomedical Research Institute, San Antonio, TX 78227 USA
| |
Collapse
|
6
|
Ramos L, Lunney JK, Gonzalez-Juarrero M. Neonatal and infant immunity for tuberculosis vaccine development: importance of age-matched animal models. Dis Model Mech 2020; 13:dmm045740. [PMID: 32988990 PMCID: PMC7520460 DOI: 10.1242/dmm.045740] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Neonatal and infant immunity differs from that of adults in both the innate and adaptive arms, which are critical contributors to immune-mediated clearance of infection and memory responses elicited during vaccination. The tuberculosis (TB) research community has openly admitted to a vacuum of knowledge about neonatal and infant immune responses to Mycobacterium tuberculosis (Mtb) infection, especially in the functional and phenotypic attributes of memory T cell responses elicited by the only available vaccine for TB, the Bacillus Calmette-Guérin (BCG) vaccine. Although BCG vaccination has variable efficacy in preventing pulmonary TB during adolescence and adulthood, 80% of endemic TB countries still administer BCG at birth because it has a good safety profile and protects children from severe forms of TB. As such, new vaccines must work in conjunction with BCG at birth and, thus, it is essential to understand how BCG shapes the immune system during the first months of life. However, many aspects of the neonatal and infant immune response elicited by vaccination with BCG remain unknown, as only a handful of studies have followed BCG responses in infants. Furthermore, most animal models currently used to study TB vaccine candidates rely on adult-aged animals. This presents unique challenges when transitioning to human trials in neonates or infants. In this Review, we focus on vaccine development in the field of TB and compare the relative utility of animal models used thus far to study neonatal and infant immunity. We encourage the development of neonatal animal models for TB, especially the use of pigs.
Collapse
Affiliation(s)
- Laylaa Ramos
- Mycobacteria Research Laboratories, Microbiology Immunology and Pathology Department, Colorado State University, 1682 Campus Delivery, Fort Collins, CO 80523, USA
| | - Joan K Lunney
- Animal Parasitic Diseases Laboratory, BARC, NEA, ARS, USDA Building 1040, Room 103, Beltsville, MD 20705, USA
| | - Mercedes Gonzalez-Juarrero
- Mycobacteria Research Laboratories, Microbiology Immunology and Pathology Department, Colorado State University, 1682 Campus Delivery, Fort Collins, CO 80523, USA
| |
Collapse
|
7
|
Curtis AD, Walter KA, Nabi R, Jensen K, Dwivedi A, Pollara J, Ferrari G, Van Rompay KK, Amara RR, Kozlowski PA, De Paris K. Oral Coadministration of an Intramuscular DNA/Modified Vaccinia Ankara Vaccine for Simian Immunodeficiency Virus Is Associated with Better Control of Infection in Orally Exposed Infant Macaques. AIDS Res Hum Retroviruses 2019; 35:310-325. [PMID: 30303405 PMCID: PMC6434602 DOI: 10.1089/aid.2018.0180] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The majority of human immunodeficiency virus (HIV) type 1 infections in infants are acquired orally through breastfeeding. Toward development of a pediatric HIV vaccine to prevent breastmilk transmission, we tested the efficacy of a simultaneous oral and intramuscular (IM) vaccination regimen for preventing oral simian immunodeficiency virus (SIV) transmission in infant rhesus macaques. Two groups of neonatal macaques were immunized with DNA encoding SIV virus-like particles (DNA-SIV) on weeks 0 and 3, then boosted with modified vaccinia Ankara (MVA) virus expressing SIV antigens (MVA-SIV) on weeks 6 and 9. One group was prime/boosted by the IM route only. Another group was immunized with DNA by both the IM and topical oral (O) buccal routes, and boosted with MVA-SIV by both the IM and sublingual (SL) routes. A third group of control animals received saline by O + IM routes on weeks 0 and 3, and empty MVA by SL + IM routes on weeks 6 and 9. On week 12, infants were orally challenged once weekly with SIVmac251 until infected. The vaccine regimen that included oral routes resulted in reduced peak viremia. The rate of infection acquisition in vaccinated infants was found to be associated with prechallenge intestinal immunoglobulin G (IgG) responses to SIV gp120 and V1V2. Peak viremia was inversely correlated with postinfection intestinal IgG responses to gp120, gp41, and V1V2. These results suggest that codelivery of a pediatric HIV vaccine by an oral route may be superior to IM-only regimens for generating mucosal antibodies and preventing HIV breastmilk transmission in neonates.
Collapse
Affiliation(s)
- Alan D. Curtis
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Korey A. Walter
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University, New Orleans, Louisiana
| | - Rafiq Nabi
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University, New Orleans, Louisiana
| | - Kara Jensen
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Aanini Dwivedi
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Justin Pollara
- Duke University Medical Center, Human Vaccine Institute, Durham, North Carolina
| | - Guido Ferrari
- Duke University Medical Center, Human Vaccine Institute, Durham, North Carolina
| | | | - Rama R. Amara
- Emory University and Yerkes National Primate Research Center, Atlanta, Georgia
| | - Pamela A. Kozlowski
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University, New Orleans, Louisiana
| | - Kristina De Paris
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| |
Collapse
|
8
|
Soundarya JSV, Ranganathan UD, Tripathy SP. Current trends in tuberculosis vaccine. Med J Armed Forces India 2019; 75:18-24. [PMID: 30705473 DOI: 10.1016/j.mjafi.2018.12.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 12/26/2018] [Indexed: 12/21/2022] Open
Abstract
Despite the global efforts made to control tuberculosis (TB) and the large number of available new anti-TB drugs, TB still affects one-third of the world population. The conventional vaccine bacille Calmette-Guérin (BCG) shows varying efficacy in different populations, and there are safety issues in immunocompromised patients. Hence, there is an urgent requirement for a new and better TB vaccine candidate than BCG. There are several alternate vaccines available for TB such as DNA, subunit, adjuvant, and live-attenuated vaccines. Use of auxotrophic vaccine is an emerging technology. Newer vaccine technologies include vaccine delivery methods such as adenovirus- and cytomegalovirus (CMV)-based vector delivery, chimeric monoclonal antibody, single-chain fragment variable, RNA-lipoplexes, and nanoparticle-based technology. Based on its application, TB vaccines are classified as conventional, prophylactic, booster, therapeutic, and reinfection preventive vaccines. Currently, there are 12 vaccine candidates in clinical trials. In this review, we have briefly discussed about each of these vaccines in different phases of clinical trials. These vaccines should be analyzed further for developing a safe and more efficacious vaccine for TB.
Collapse
Affiliation(s)
- J S V Soundarya
- PhD Research Scholar, Department of Immunology, National Institute for Research in Tuberculosis, Chennai 600031, India
| | - Uma Devi Ranganathan
- Scientist 'D', Department of Immunology, National Institute for Research in Tuberculosis, Chennai 600031, India
| | - Srikanth P Tripathy
- Scientist 'G' & Director-in-charge, National Institute for Research in Tuberculosis, Chennai 600031, India
| |
Collapse
|
9
|
Kilpeläinen A, Maya-Hoyos M, Saubí N, Soto CY, Joseph Munne J. Advances and challenges in recombinant Mycobacterium bovis BCG-based HIV vaccine development: lessons learned. Expert Rev Vaccines 2018; 17:1005-1020. [PMID: 30300040 DOI: 10.1080/14760584.2018.1534588] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
INTRODUCTION Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome, tuberculosis, and malaria are responsible for most human deaths produced by infectious diseases worldwide. Vaccination against HIV requires generation of memory T cells and neutralizing antibodies, mucosal immunity, and stimulation of an innate immune responses. In this context, the use of Mycobacterium bovis bacillus Calmette-Guérin (BCG) as a live vaccine vehicle is a promising approach for T-cell induction. AREAS COVERED In this review, we provide a comprehensive summary of the literature regarding immunogenicity studies in animal models performed since 2005. Furthermore, we provide expert commentary and 5-year view on how the development of potential recombinant BCG-based HIV vaccines involves careful selection of the HIV antigen, expression vectors, promoters, BCG strain, preclinical animal models, influence of preexisting immunity, and safety issues, for the rational design of recombinant BCG:HIV vaccines to prevent HIV transmission in the general population. EXPERT COMMENTARY The three critical issues to be considered when developing a rBCG:HIV vaccine are codon optimization, antigen localization, and plasmid stability in vivo. The use of integrative expression vectors are likely to improve the mycobacterial vaccine stability and immunogenicity to develop not only recombinant BCG-based vaccines expressing second generation of HIV-1 immunogens but also other major pediatric pathogens to prime protective responses shortly following birth.
Collapse
Affiliation(s)
- Athina Kilpeläinen
- a Catalan Center for HIV Vaccine Research and Development, AIDS Research Unit, Infectious Diseases Department, Hospital Clínic/IDIBAPS, School of Medicine , University of Barcelona , Barcelona , Spain
| | - Milena Maya-Hoyos
- b Chemistry Department, Faculty of Sciences , Universidad Nacional de Colombia, Ciudad Universitaria , Bogotá , Colombia
| | - Narcís Saubí
- a Catalan Center for HIV Vaccine Research and Development, AIDS Research Unit, Infectious Diseases Department, Hospital Clínic/IDIBAPS, School of Medicine , University of Barcelona , Barcelona , Spain
| | - Carlos Y Soto
- b Chemistry Department, Faculty of Sciences , Universidad Nacional de Colombia, Ciudad Universitaria , Bogotá , Colombia
| | - Joan Joseph Munne
- a Catalan Center for HIV Vaccine Research and Development, AIDS Research Unit, Infectious Diseases Department, Hospital Clínic/IDIBAPS, School of Medicine , University of Barcelona , Barcelona , Spain
| |
Collapse
|
10
|
Hashish E, Merwad A, Elgaml S, Amer A, Kamal H, Elsadek A, Marei A, Sitohy M. Mycobacterium marinum infection in fish and man: epidemiology, pathophysiology and management; a review. Vet Q 2018; 38:35-46. [PMID: 29493404 PMCID: PMC6831007 DOI: 10.1080/01652176.2018.1447171] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Mycobacterium marinum is an opportunistic pathogen inducing infection in fresh and marine water fish. This pathogen causes necrotizing granuloma like tuberculosis, morbidity and mortality in fish. The cell wall-associated lipid phthiocerol dimycocerosates, phenolic glycolipids and ESAT-6 secretion system 1 (ESX-1) are the conserved virulence determinant of the organism. Human infections with Mycobacterium marinum hypothetically are classified into four clinical categories (type I–type IV) and have been associated with the exposure of damaged skin to polluted water from fish pools or contacting objects contaminated with infected fish. Fish mycobacteriosis is clinically manifested and characterized in man by purple painless nodules, liable to develop into superficial crusting ulceration with scar formation. Early laboratory diagnosis of M. marinum including histopathology, culture and PCR is essential and critical as the clinical response to antibiotics requires months to be attained. The pathogenicity and virulence determinants of M. marinum need to be thoroughly and comprehensively investigated and understood. In spite of accumulating information on this pathogen, the different relevant data should be compared, connected and globally compiled. This article is reviewing the epidemiology, virulence factors, diagnosis and disease management in fish while casting light on the potential associated public health hazards.
Collapse
Affiliation(s)
- Emad Hashish
- a Department of Clinical Pathology, Faculty of Veterinary Medicine , Zagazig University , Egypt
| | - Abdallah Merwad
- b Department of Zoonoses, Faculty of Veterinary Medicine , Zagazig University , Egypt
| | - Shimaa Elgaml
- a Department of Clinical Pathology, Faculty of Veterinary Medicine , Zagazig University , Egypt
| | - Ali Amer
- c Tuberculosis Unit , Animal Health Research Institute (AHRI) , Giza , Egypt
| | - Huda Kamal
- d Department of Meat Hygiene , National Research Center (NRC) , Zagazig , Egypt
| | - Ahmed Elsadek
- e Immunology Research Lab, Immunology Division, Department of Microbiology and Immunology, Faculty of Medicine , Zagazig University , Egypt
| | - Ayman Marei
- e Immunology Research Lab, Immunology Division, Department of Microbiology and Immunology, Faculty of Medicine , Zagazig University , Egypt
| | - Mahmoud Sitohy
- f Department of Biochemistry, Faculty of Agriculture , Zagazig University , Egypt
| |
Collapse
|
11
|
Curtis AD, Jensen K, Van Rompay KK, Amara RR, Kozlowski PA, De Paris K. A simultaneous oral and intramuscular prime/sublingual boost with a DNA/Modified Vaccinia Ankara viral vector-based vaccine induces simian immunodeficiency virus-specific systemic and mucosal immune responses in juvenile rhesus macaques. J Med Primatol 2018; 47:288-297. [PMID: 30204253 PMCID: PMC6158111 DOI: 10.1111/jmp.12372] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/24/2018] [Indexed: 01/22/2023]
Abstract
BACKGROUND A pediatric vaccine to prevent breast milk transmission of human immunodeficiency virus (HIV) may generate greater immune responses at viral entry sites if given by an oral route. METHODS We compared immune responses induced in juvenile macaques by prime/boosting with simian immunodeficiency virus (SIV)-expressing DNA/modified vaccinia Ankara virus (MVA) by the intramuscular route (IM), the oral (O)/tonsillar routes (T), the O/sublingual (SL) routes, and O+IM/SL routes. RESULTS O/T or O/SL immunization generated SIV-specific T cells in mucosal tissues but failed to induce SIV-specific IgA in saliva or stool or IgG in plasma. IM/IM or O+IM/SL generated humoral and cellular responses to SIV. IM/IM generated greater frequencies of TFH in spleen, but O+IM/SL animals had higher avidity plasma IgG and more often demonstrated mucosal IgA responses. CONCLUSION These results suggest that codelivery of HIV DNA/MVA vaccines by the oral and IM routes might be optimal for generating both systemic and mucosal antibodies.
Collapse
Affiliation(s)
- Alan D. Curtis
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Kara Jensen
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Koen K.A. Van Rompay
- California National Primate Research Center, University of California, Davis, CA, 95616, USA
| | - Rama R. Amara
- Yerkes National Primate Research Center and Emory University, Atlanta, GA, 30322, USA
| | - Pamela A. Kozlowski
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, USA
| | - Kristina De Paris
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| |
Collapse
|
12
|
Abstract
All bacteria utilize pathways to export proteins from the cytoplasm to the bacterial cell envelope or extracellular space. Many exported proteins function in essential physiological processes or in virulence. Consequently, the responsible protein export pathways are commonly essential and/or are important for pathogenesis. The general Sec protein export pathway is conserved and essential in all bacteria, and it is responsible for most protein export. The energy for Sec export is provided by the SecA ATPase. Mycobacteria and some Gram-positive bacteria have two SecA paralogs: SecA1 and SecA2. SecA1 is essential and works with the canonical Sec pathway to perform the bulk of protein export. The nonessential SecA2 exports a smaller subset of proteins and is required for the virulence of pathogens such as Mycobacterium tuberculosis. In this article, we review our current understanding of the mechanism of the SecA1 and SecA2 export pathways and discuss some of their better-studied exported substrates. We focus on proteins with established functions in M. tuberculosis pathogenesis and proteins that suggest potential roles for SecA1 and SecA2 in M. tuberculosis dormancy.
Collapse
|
13
|
Carryl H, Van Rompay KKA, De Paris K, Burke MW. Hippocampal Neuronal Loss in Infant Macaques Orally Infected with Virulent Simian Immunodeficiency Virus (SIV). Brain Sci 2017; 7:E40. [PMID: 28394273 PMCID: PMC5406697 DOI: 10.3390/brainsci7040040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/04/2017] [Accepted: 04/05/2017] [Indexed: 12/21/2022] Open
Abstract
The neurological impact of Human Immunodeficiency Virus (HIV) on children includes loss of brain growth, motor abnormalities and cognitive dysfunction. Despite early antiretroviral treatment (ART) intervention to suppress viral load, neurological consequences of perinatal HIV-1 infection persist. Utilizing the pediatric simian immunodeficiency virus (SIV) infection model, we tested the hypothesis that early-life SIV infection depletes neuronal population in the hippocampus. A total of 22 ART-naïve infant rhesus macaques (Macaca mulatta) from previous studies were retrospectively analyzed. Infant macaques were either intravenously (IV) inoculated with highly virulent SIVmac251 at ~1 week of age and monitored for 6-10 weeks, or orally challenged with SIVmac251 from week 9 of age onwards with a monitoring period of 10-23 weeks post-infection (19-34 weeks of age), and SIV-uninfected controls were euthanized at 16-17 weeks of age. We have previously reported that the IV SIVmac251-infected neonatal macaques (Group 1) displayed a 42% neuronal reduction throughout the hippocampal cornu ammonis (CA) fields. The orally-infected infant macaques displayed a 75% neuronal reduction in the CA1 region compared to controls and 54% fewer neurons than IV SIV infants. The CA2 region showed a similar pattern, with a 67% reduction between orally-infected SIV subjects and controls and a 40% difference between IV-and orally-infected SIV groups. In the CA3 region, there were no significant differences between these groups, however both SIV-infected groups had significantly fewer pyramidal neurons than control subjects. There was no correlation between plasma viral load and neuronal populations in any of the CA fields. The loss of hippocampal neurons may contribute to the rapid neurocognitive decline associated with pediatric HIV infection. While each subfield showed vulnerability to SIV infection, the CA1 and CA2 subregions demonstrated a potentially enhanced vulnerability to pediatric SIV infection. These data underscore the need for early diagnosis and treatment, including therapeutics targeting the central nervous system (CNS).
Collapse
Affiliation(s)
- Heather Carryl
- Department of Physiology and Biophysics, Howard University, Washington, DC 20059, USA.
| | - Koen K A Van Rompay
- California National Primate Research Center, University of California Davis, Davis, CA 95616, USA.
| | - Kristina De Paris
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA.
| | - Mark W Burke
- Department of Physiology and Biophysics, Howard University, Washington, DC 20059, USA.
| |
Collapse
|
14
|
Jensen K, Dela Pena-Ponce MG, Piatak M, Shoemaker R, Oswald K, Jacobs WR, Fennelly G, Lucero C, Mollan KR, Hudgens MG, Amedee A, Kozlowski PA, Estes JD, Lifson JD, Van Rompay KKA, Larsen M, De Paris K. Balancing Trained Immunity with Persistent Immune Activation and the Risk of Simian Immunodeficiency Virus Infection in Infant Macaques Vaccinated with Attenuated Mycobacterium tuberculosis or Mycobacterium bovis BCG Vaccine. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:e00360-16. [PMID: 27655885 PMCID: PMC5216431 DOI: 10.1128/cvi.00360-16] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 09/12/2016] [Indexed: 12/14/2022]
Abstract
Our goal is to develop a pediatric combination vaccine to protect the vulnerable infant population against human immunodeficiency virus type 1 (HIV-1) and tuberculosis (TB) infections. The vaccine consists of an auxotroph Mycobacterium tuberculosis strain that coexpresses HIV antigens. Utilizing an infant rhesus macaque model, we have previously shown that this attenuated M. tuberculosis (AMtb)-simian immunodeficiency virus (SIV) vaccine is immunogenic, and although the vaccine did not prevent oral SIV infection, a subset of vaccinated animals was able to partially control virus replication. However, unexpectedly, vaccinated infants required fewer SIV exposures to become infected compared to naive controls. Considering that the current TB vaccine, Mycobacterium bovis bacillus Calmette-Guérin (BCG), can induce potent innate immune responses and confer pathogen-unspecific trained immunity, we hypothesized that an imbalance between enhanced myeloid cell function and immune activation might have influenced the outcome of oral SIV challenge in AMtb-SIV-vaccinated infants. To address this question, we used archived samples from unchallenged animals from our previous AMtb-SIV vaccine studies and vaccinated additional infant macaques with BCG or AMtb only. Our results show that vaccinated infants, regardless of vaccine strain or regimen, had enhanced myeloid cell responses. However, CD4+ T cells were concurrently activated, and the persistence of these activated target cells in oral and/or gastrointestinal tissues may have facilitated oral SIV infection. Immune activation was more pronounced in BCG-vaccinated infant macaques than in AMtb-vaccinated infant macaques, indicating a role for vaccine attenuation. These findings underline the importance of understanding the interplay of vaccine-induced immunity and immune activation and its effect on HIV acquisition risk and outcome in infants.
Collapse
Affiliation(s)
- Kara Jensen
- Department of Microbiology and Immunology and Center for AIDS Research, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Myra Grace Dela Pena-Ponce
- Department of Microbiology and Immunology and Center for AIDS Research, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Michael Piatak
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Rebecca Shoemaker
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Kelli Oswald
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | | | - Glenn Fennelly
- Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Carissa Lucero
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Katie R Mollan
- Lineberger Cancer Center and Center for AIDS Research, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Michael G Hudgens
- Gillings School of Global Public Health and Center for AIDS Research, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Angela Amedee
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Pamela A Kozlowski
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Jacob D Estes
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Jeffrey D Lifson
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Koen K A Van Rompay
- California National Primate Research Center, University of California, Davis, Davis, California, USA
| | - Michelle Larsen
- Albert Einstein College of Medicine, New York, New York, USA
| | - Kristina De Paris
- Department of Microbiology and Immunology and Center for AIDS Research, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| |
Collapse
|
15
|
Amorim Franco TM, Hegde S, Blanchard JS. Chemical Mechanism of the Branched-Chain Aminotransferase IlvE from Mycobacterium tuberculosis. Biochemistry 2016; 55:6295-6303. [PMID: 27780341 DOI: 10.1021/acs.biochem.6b00928] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The biosynthetic pathway of the branched-chain amino acids is essential for Mycobacterium tuberculosis growth and survival. We report here the kinetic and chemical mechanism of the pyridoxal 5'-phosphate (PLP)-dependent branched-chain aminotransferase, IlvE, from M. tuberculosis (MtIlvE). This enzyme is responsible for the final step of the synthesis of the branched-chain amino acids isoleucine, leucine, and valine. As seen in other aminotransferases, MtIlvE displays a ping-pong kinetic mechanism. pK values were identified from the pH dependence on V as well as V/K, indicating that the phosphate ester of the PLP cofactor, and the α-amino group from l-glutamate and the active site Lys204, play roles in acid-base catalysis and binding, respectively. An intrinsic primary kinetic isotope effect was identified for the α-C-H bond cleavage of l-glutamate. Large solvent kinetic isotope effect values for the ping and pong half-reactions were also identified. The absence of a quininoid intermediate in combination with the Dkobs in our multiple kinetic isotope effects under single-turnover conditions suggests a concerted type of mechanism. The deprotonation of C2 of l-glutamate and the protonation of C4' of the PLP cofactor happen synchronously in the ping half-reaction. A chemical mechanism is proposed on the basis of the results obtained here.
Collapse
Affiliation(s)
- Tathyana M Amorim Franco
- Department of Biochemistry, Albert Einstein College of Medicine , 1300 Morris Park Avenue, Bronx, New York 10461, United States
| | - Subray Hegde
- Department of Biochemistry, Albert Einstein College of Medicine , 1300 Morris Park Avenue, Bronx, New York 10461, United States
| | - John S Blanchard
- Department of Biochemistry, Albert Einstein College of Medicine , 1300 Morris Park Avenue, Bronx, New York 10461, United States
| |
Collapse
|
16
|
Sobh A, Bonilla FA. Vaccination in Primary Immunodeficiency Disorders. THE JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY-IN PRACTICE 2016; 4:1066-1075. [DOI: 10.1016/j.jaip.2016.09.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/21/2016] [Accepted: 09/21/2016] [Indexed: 02/07/2023]
|
17
|
Jensen K, Nabi R, Van Rompay KKA, Robichaux S, Lifson JD, Piatak M, Jacobs WR, Fennelly G, Canfield D, Mollan KR, Hudgens MG, Larsen MH, Amedee AM, Kozlowski PA, De Paris K. Vaccine-Elicited Mucosal and Systemic Antibody Responses Are Associated with Reduced Simian Immunodeficiency Viremia in Infant Rhesus Macaques. J Virol 2016; 90:7285-7302. [PMID: 27252535 PMCID: PMC4984660 DOI: 10.1128/jvi.00481-16] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 05/25/2016] [Indexed: 12/28/2022] Open
Abstract
UNLABELLED Despite significant progress in reducing peripartum mother-to-child transmission (MTCT) of human immunodeficiency virus (HIV) with antiretroviral therapy (ART), continued access to ART throughout the breastfeeding period is still a limiting factor, and breast milk exposure to HIV accounts for up to 44% of MTCT. As abstinence from breastfeeding is not recommended, alternative means are needed to prevent MTCT of HIV. We have previously shown that oral vaccination at birth with live attenuated Mycobacterium tuberculosis strains expressing simian immunodeficiency virus (SIV) genes safely induces persistent SIV-specific cellular and humoral immune responses both systemically and at the oral and intestinal mucosa. Here, we tested the ability of oral M. tuberculosis vaccine strains expressing SIV Env and Gag proteins, followed by systemic heterologous (MVA-SIV Env/Gag/Pol) boosting, to protect neonatal macaques against oral SIV challenge. While vaccination did not protect infant macaques against oral SIV acquisition, a subset of immunized animals had significantly lower peak viremia which inversely correlated with prechallenge SIV Env-specific salivary and intestinal IgA responses and higher-avidity SIV Env-specific IgG in plasma. These controller animals also maintained CD4(+) T cell populations better and showed reduced tissue pathology compared to noncontroller animals. We show that infants vaccinated at birth can develop vaccine-induced SIV-specific IgA and IgG antibodies and cellular immune responses within weeks of life. Our data further suggest that affinity maturation of vaccine-induced plasma antibodies and induction of mucosal IgA responses at potential SIV entry sites are associated with better control of viral replication, thereby likely reducing SIV morbidity. IMPORTANCE Despite significant progress in reducing peripartum MTCT of HIV with ART, continued access to ART throughout the breastfeeding period is still a limiting factor. Breast milk exposure to HIV accounts for up to 44% of MTCT. Alternative measures, in addition to ART, are needed to achieve the goal of an AIDS-free generation. Pediatric HIV vaccines constitute a core component of such efforts. The results of our pediatric vaccine study highlight the potential importance of vaccine-elicited mucosal Env-specific IgA responses in combination with high-avidity systemic Env-specific IgG in protection against oral SIV transmission and control of viral replication in infant macaques. The induction of potent mucosal IgA antibodies by our vaccine is remarkable considering the age-dependent development of mucosal IgA responses postbirth. A deeper understanding of postnatal immune development may inform the design of improved vaccine strategies to enhance systemic and mucosal SIV/HIV antibody responses.
Collapse
Affiliation(s)
- Kara Jensen
- Department of Microbiology and Immunology and Center for AIDS Research, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Rafiq Nabi
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Koen K A Van Rompay
- California National Primate Research Center, University of California at Davis, Davis, California, USA
| | - Spencer Robichaux
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Jeffrey D Lifson
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, Maryland, USA
| | - Michael Piatak
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, Maryland, USA
| | | | - Glenn Fennelly
- Albert Einstein College of Medicine, New York, New York, USA
| | - Don Canfield
- California National Primate Research Center, University of California at Davis, Davis, California, USA
| | - Katie R Mollan
- Lineberger Cancer Center and Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Michael G Hudgens
- Gillings School of Public Health and Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | | | - Angela M Amedee
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Pamela A Kozlowski
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Kristina De Paris
- Department of Microbiology and Immunology and Center for AIDS Research, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| |
Collapse
|
18
|
Abstract
Infectious diseases have plagued humankind throughout history and have posed serious public health problems. Yet vaccines have eradicated smallpox and antibiotics have drastically decreased the mortality rate of many infectious agents. These remarkable successes in the control of infections came from knowing the causative agents of the diseases, followed by serendipitous discoveries of attenuated viruses and antibiotics. The discovery of DNA as genetic material and the understanding of how this information translates into specific phenotypes have changed the paradigm for developing new vaccines, drugs, and diagnostic tests. Knowledge of the mechanisms of immunity and mechanisms of action of drugs has led to new vaccines and new antimicrobial agents. The key to the acquisition of the knowledge of these mechanisms has been identifying the elemental causes (i.e., genes and their products) that mediate immunity and drug resistance. The identification of these genes is made possible by being able to transfer the genes or mutated forms of the genes into causative agents or surrogate hosts. Such an approach was limited in Mycobacterium tuberculosis by the difficulty of transferring genes or alleles into M. tuberculosis or a suitable surrogate mycobacterial host. The construction of shuttle phasmids-chimeric molecules that replicate in Escherichia coli as plasmids and in mycobacteria as mycobacteriophages-was instrumental in developing gene transfer systems for M. tuberculosis. This review will discuss M. tuberculosis genetic systems and their impact on tuberculosis research.
Collapse
|
19
|
Abstract
A brief history of vaccination is presented since the Jenner's observation, through the first golden age of vaccinology (from Pasteur's era to 1938), the second golden age (from 1940 to 1970), until the current period. In the first golden age, live, such as Bacille Calmette Guérin (BCG), and yellow fever, inactivated, such as typhoid, cholera, plague, and influenza, and subunit vaccines, such as tetanus and diphtheria toxoids, have been developed. In the second golden age, the cell culture technology enabled polio, measles, mumps, and rubella vaccines be developed. In the era of modern vaccines, in addition to the conjugate polysaccharide, hepatitis A, oral typhoid, and varicella vaccines, the advent of molecular biology enabled to develop hepatitis B, acellular pertussis, papillomavirus, and rotavirus recombinant vaccines. Great successes have been achieved in the fight against infectious diseases, including the smallpox global eradication, the nearly disappearance of polio, the control of tetanus, diphtheria, measles, rubella, yellow fever, and rabies. However, much work should still be done for improving old vaccines, such as BCG, anthrax, smallpox, plague, or for developing effective vaccines against old or emerging infectious threats, such as human-immunodeficiency-virus, malaria, hepatitis C, dengue, respiratory-syncytial-virus, cytomegalovirus, multiresistant bacteria, Clostridium difficile, Ebola virus. In addition to search for innovative and effective vaccines and global infant coverage, even risk categories should adequately be protected. Despite patients under immunosuppressive therapy are globally increasing, their vaccine coverage is lower than recommended, even in developed and affluent countries.
Collapse
Affiliation(s)
| | - Simonetta Salemi
- c S. Andrea University Hospital , Via di Grottarossa Rome, Italy
| | - Raffaele D'Amelio
- b Sapienza University of Rome , Department of Clinical and Molecular Medicine , Via di Grottarossa Rome, Italy.,c S. Andrea University Hospital , Via di Grottarossa Rome, Italy
| |
Collapse
|
20
|
Flynn JL, Gideon HP, Mattila JT, Lin PL. Immunology studies in non-human primate models of tuberculosis. Immunol Rev 2015; 264:60-73. [PMID: 25703552 DOI: 10.1111/imr.12258] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Non-human primates, primarily macaques, have been used to study tuberculosis for decades. However, in the last 15 years, this model has been refined substantially to allow careful investigations of the immune response and host-pathogen interactions in Mycobacterium tuberculosis infection. Low-dose challenge with fully virulent strains in cynomolgus macaques result in the full clinical spectrum seen in humans, including latent and active infection. Reagents from humans are usually cross-reactive with macaques, further facilitating the use of this model system to study tuberculosis. Finally, macaques develop the spectrum of granuloma types seen in humans, providing a unique opportunity to investigate bacterial and host factors at the local (lung and lymph node) level. Here, we review the past decade of immunology and pathology studies in macaque models of tuberculosis.
Collapse
Affiliation(s)
- JoAnne L Flynn
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | | | | | | |
Collapse
|
21
|
Ng TW, Saavedra-Ávila NA, Kennedy SC, Carreño LJ, Porcelli SA. Current efforts and future prospects in the development of live mycobacteria as vaccines. Expert Rev Vaccines 2015; 14:1493-507. [PMID: 26366616 DOI: 10.1586/14760584.2015.1089175] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The development of more effective vaccines against Mycobacterium tuberculosis (Mtb) remains a major goal in the effort to reduce the enormous global burden of disease caused by this pathogen. Whole-cell vaccines based on live mycobacteria with attenuated virulence represent an appealing approach, providing broad antigen exposure and intrinsic adjuvant properties to prime durable immune responses. However, designing vaccine strains with an optimal balance between attenuation and immunogenicity has proven to be extremely challenging. Recent basic and clinical research efforts have broadened our understanding of Mtb pathogenesis and created numerous new vaccine candidates that have been designed to overcome different aspects of immune evasion by Mtb. In this review, we provide an overview of the current efforts to create improved vaccines against tuberculosis based on modifications of live attenuated mycobacteria. In addition, we discuss the use of such vaccine strains as vectors for stimulating protective immunity against other infectious diseases and cancers.
Collapse
Affiliation(s)
- Tony W Ng
- a 1 Albert Einstein College of Medicine - Microbiology & Immunology, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Noemí A Saavedra-Ávila
- a 1 Albert Einstein College of Medicine - Microbiology & Immunology, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Steven C Kennedy
- a 1 Albert Einstein College of Medicine - Microbiology & Immunology, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Leandro J Carreño
- a 1 Albert Einstein College of Medicine - Microbiology & Immunology, 1300 Morris Park Avenue, Bronx, NY 10461, USA.,b 2 Millennium Institute on Immunology and Immunotherapy, Programa Disciplinario de Inmunologia, Instituto de Ciencias Biomedicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Steven A Porcelli
- a 1 Albert Einstein College of Medicine - Microbiology & Immunology, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| |
Collapse
|
22
|
Korioth-Schmitz B, Perley CC, Sixsmith JD, Click EM, Lee S, Letvin NL, Frothingham R. Rhesus immune responses to SIV Gag expressed by recombinant BCG vectors are independent from pre-existing mycobacterial immunity. Vaccine 2015; 33:5715-5722. [PMID: 26192357 DOI: 10.1016/j.vaccine.2015.07.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 06/02/2015] [Accepted: 07/07/2015] [Indexed: 11/25/2022]
Abstract
BACKGROUND A recombinant Mycobacterium bovis BCG (rBCG) vector expressing HIV transgenes is an attractive candidate as a dual vaccine against HIV and TB. However, pre-existing immune responses to mycobacteria may influence immune responses to rBCG. We analyzed data from a rhesus rBCG trial to determine the effect of pre-existing mycobacterial immune responses on the vaccine-induced responses to the vector and expressed transgene. METHODS Indian-origin rhesus macaques were primed with rBCG expressing simian immunodeficiency virus (SIV) Gag and boosted with attenuated vaccinia NYVAC gag-pol. Mycobacteria responses were measured by Mycobacterium tuberculosis (Mtb) purified protein derivative (PPD) interferon-γ ELISpot and Mtb whole cell lysate (WCL) ELISA. SIV Gag responses were measured by SIV Gag ELISpot and by p11C tetramer binding. RESULTS Baseline Mtb PPD ELISpot responses and Mtb WCL antibody responses in rhesus macaques overlapped those in human populations. Cellular and antibody responses boosted sharply 4 weeks after rBCG vaccination. Mtb WCL antibody titers at 4 weeks correlated with baseline titers. Primates vaccinated with rBCG developed strong SIV Gag ELISpot and p11C tetramer responses after rBCG prime and NYVAC boost. There were no correlations between the pre-existing mycobacterial immune responses and the SIV Gag T cell responses after vaccination. CONCLUSIONS Rhesus immune responses to SIV Gag expressed by rBCG vectors were independent from pre-existing anti-mycobacterial immunity. Rhesus macaques may serve as a surrogate for investigations of pre-existing anti-mycobacterial immunity in humans.
Collapse
Affiliation(s)
- Birgit Korioth-Schmitz
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, United States
| | - Casey C Perley
- Duke University School of Medicine, Durham, NC 27710, United States
| | - Jaimie D Sixsmith
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, United States
| | - Eva M Click
- Duke University School of Medicine, Durham, NC 27710, United States
| | - Sunhee Lee
- Duke University School of Medicine, Durham, NC 27710, United States
| | - Norman L Letvin
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, United States
| | | |
Collapse
|
23
|
Stable Expression of Lentiviral Antigens by Quality-Controlled Recombinant Mycobacterium bovis BCG Vectors. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2015; 22:726-41. [PMID: 25924766 PMCID: PMC4478521 DOI: 10.1128/cvi.00075-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 04/22/2015] [Indexed: 12/14/2022]
Abstract
The well-established safety profile of the tuberculosis vaccine strain, Mycobacterium bovis bacille Calmette-Guérin (BCG), makes it an attractive vehicle for heterologous expression of antigens from clinically relevant pathogens. However, successful generation of recombinant BCG strains possessing consistent insert expression has encountered challenges in stability. Here, we describe a method for the development of large recombinant BCG accession lots which stably express the lentiviral antigens, human immunodeficiency virus (HIV) gp120 and simian immunodeficiency virus (SIV) Gag, using selectable leucine auxotrophic complementation. Successful establishment of vaccine stability stems from stringent quality control criteria which not only screen for highly stable complemented BCG ΔleuCD transformants but also thoroughly characterize postproduction quality. These parameters include consistent production of correctly sized antigen, retention of sequence-pure plasmid DNA, freeze-thaw recovery, enumeration of CFU, and assessment of cellular aggregates. Importantly, these quality assurance procedures were indicative of overall vaccine stability, were predictive for successful antigen expression in subsequent passaging both in vitro and in vivo, and correlated with induction of immune responses in murine models. This study has yielded a quality-controlled BCG ΔleuCD vaccine expressing HIV gp120 that retained stable full-length expression after 10(24)-fold amplification in vitro and following 60 days of growth in mice. A second vaccine lot expressed full-length SIV Gag for >10(68)-fold amplification in vitro and induced potent antigen-specific T cell populations in vaccinated mice. Production of large, well-defined recombinant BCG ΔleuCD lots can allow confidence that vaccine materials for immunogenicity and protection studies are not negatively affected by instability or differences between freshly grown production batches.
Collapse
|
24
|
Abstract
This chapter reviews papers mostly written since 2005 that report results using live attenuated bacterial vectors to deliver after administration through mucosal surfaces, protective antigens, and DNA vaccines, encoding protective antigens to induce immune responses and/or protective immunity to pathogens that colonize on or invade through mucosal surfaces. Papers that report use of such vaccine vector systems for parenteral vaccination or to deal with nonmucosal pathogens or do not address induction of mucosal antibody and/or cellular immune responses are not reviewed.
Collapse
|
25
|
Abstract
Nonhuman primates have emerged as an excellent model of human tuberculosis, in large part because they recapitulate the full spectrum of infection outcome and pathology seen in humans. Several variables inherent to the nonhuman primate models of tuberculosis are discussed in this review, including the monkey species, Mycobacterium tuberculosis strains, and routes of infection, all of which can influence the model to be chosen for various studies. New technologies for studying the microbiology, immunology, and pathogenesis of tuberculosis in nonhuman primates have greatly expanded the capabilities of this model for basic and translational studies, including the development and testing of new treatment and prevention strategies for tuberculosis.
Collapse
Affiliation(s)
- Charles A Scanga
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - JoAnne L Flynn
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| |
Collapse
|
26
|
Diogo GR, Reljic R. Development of a new tuberculosis vaccine: is there value in the mucosal approach? Immunotherapy 2014; 6:1001-13. [DOI: 10.2217/imt.14.62] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
TB is a global health problem, killing 1.5 million people every year. The only currently available vaccine, Mycobacterium bovis BCG, is effective against severe childhood forms, but it demonstrates a variable efficacy against the pulmonary form of TB in adults. Many of these adult TB cases result from the reactivation of an initially controlled, latent Mycobacterium tuberculosis infection. Effective prophylactic vaccination remains the key long-term strategy for combating TB. Continued belief in reaching this goal requires unrelenting innovation in the formulation and delivery of candidate vaccines. It is also based on the assumption, that the failure of recent human vaccine trials could have been due to a suboptimal vaccine design and delivery, and therefore should not erode the key principle that a TB vaccine is an attainable target. This report gives a brief overview of the mucosal immune system in the context of M. tuberculosis infection, and focuses on the most recent advances in the field of mucosal TB vaccine development, with a specific emphasis on subunit TB vaccines.
Collapse
Affiliation(s)
- Gil Reynolds Diogo
- St George's Hospital, Institute of Infection & Immunity, St George's University of London, London, SW17 0RE, UK
| | - Rajko Reljic
- St George's Hospital, Institute of Infection & Immunity, St George's University of London, London, SW17 0RE, UK
| |
Collapse
|
27
|
Specialized transduction designed for precise high-throughput unmarked deletions in Mycobacterium tuberculosis. mBio 2014; 5:e01245-14. [PMID: 24895308 PMCID: PMC4049104 DOI: 10.1128/mbio.01245-14] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Specialized transduction has proven to be useful for generating deletion mutants in most mycobacteria, including virulent Mycobacterium tuberculosis. We have improved this system by developing (i) a single-step strategy for the construction of allelic exchange substrates (AES), (ii) a temperature-sensitive shuttle phasmid with a greater cloning capacity than phAE87, and (iii) bacteriophage-mediated transient expression of site-specific recombinase to precisely excise antibiotic markers. The methods ameliorate rate-limiting steps in strain construction in these difficult-to-manipulate bacteria. The new methods for strain construction were demonstrated to generalize to all classes of genes and chromosomal loci by generating more than 100 targeted single- or multiple-deletion substitutions. These improved methods pave the way for the generation of a complete ordered library of M. tuberculosis null strains, where each strain is deleted for a single defined open reading frame in M. tuberculosis. This work reports major advances in the methods of genetics applicable to all mycobacteria, including but not limited to virulent M. tuberculosis, which would facilitate comparative genomics to identify drug targets, genetic validation of proposed pathways, and development of an effective vaccine. This study presents all the new methods developed and the improvements to existing methods in an integrated way. The work presented in this study could increase the pace of mycobacterial genetics significantly and will immediately be of wide use. These new methods are transformative and allow for the undertaking of construction of what has been one of the most fruitful resources in model systems: a comprehensive, ordered library set of the strains, each of which is deleted for a single defined open reading frame.
Collapse
|
28
|
Wang W, Oldfield E. Biometallorganische Chemie mit IspG und IspH: Struktur, Funktion und Hemmung der an der Isoprenoid-Biosynthese beteiligten [Fe 4S 4]-Proteine. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201306712] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
29
|
Wang W, Oldfield E. Bioorganometallic chemistry with IspG and IspH: structure, function, and inhibition of the [Fe(4)S(4)] proteins involved in isoprenoid biosynthesis. Angew Chem Int Ed Engl 2014; 53:4294-310. [PMID: 24481599 DOI: 10.1002/anie.201306712] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Indexed: 11/12/2022]
Abstract
Enzymes of the methylerythritol phosphate pathway of isoprenoid biosynthesis are attractive anti-infective drug targets. The last two enzymes of this pathway, IspG and IspH, are [Fe4 S4 ] proteins that are not produced by humans and catalyze 2 H(+) / 2 e(-) reductions with novel mechanisms. In this Review, we summarize recent advances in structural, mechanistic, and inhibitory studies of these two enzymes. In particular, mechanistic proposals involving bioorganometallic intermediates are presented, and compared with other mechanistic possibilities. In addition, inhibitors based on substrate analogues as well as developed by rational design and compound-library screening, are discussed. The results presented support bioorganometallic catalytic mechanisms for IspG and IspH, and open up new routes to anti-infective drug design targeting [Fe4 S4 ] clusters in proteins.
Collapse
Affiliation(s)
- Weixue Wang
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (USA)
| | | |
Collapse
|
30
|
van der Woude AD, Stoop EJM, Stiess M, Wang S, Ummels R, van Stempvoort G, Piersma SR, Cascioferro A, Jiménez CR, Houben ENG, Luirink J, Pieters J, van der Sar AM, Bitter W. Analysis of SecA2-dependent substrates in Mycobacterium marinum identifies protein kinase G (PknG) as a virulence effector. Cell Microbiol 2013; 16:280-95. [PMID: 24119166 DOI: 10.1111/cmi.12221] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 09/14/2013] [Accepted: 09/24/2013] [Indexed: 02/03/2023]
Abstract
The pathogenicity of mycobacteria is closely associated with their ability to export virulence factors. For this purpose, mycobacteria possess different protein secretion systems, including the accessory Sec translocation pathway, SecA2. Although this pathway is associated with intracellular survival and virulence, the SecA2-dependent effector proteins remain largely undefined. In this work, we studied a Mycobacterium marinum secA2 mutant with an impaired capacity to initiate granuloma formation in zebrafish embryos. By comparing the proteomic profile of cell envelope fractions from the secA2 mutant with wild type M. marinum, we identified putative SecA2-dependent substrates. Immunoblotting procedures confirmed SecA2-dependent membrane localization for several of these proteins, including the virulence factor protein kinase G (PknG). Interestingly, phenotypical defects of the secA2 mutant are similar to those described for ΔpknG, including phagosomal maturation. Overexpression of PknG in the secA2 mutant restored its localization to the cell envelope. Importantly, PknG-overexpression also partially restored the virulence of the secA2 mutant, as indicated by enhanced infectivity in zebrafish embryos and restored inhibition of phagosomal maturation. These results suggest that SecA2-dependent membrane localization of PknG is an important determinant for M. marinum virulence.
Collapse
Affiliation(s)
- Aniek D van der Woude
- Department of Medical Microbiology and Infection Control, VU University Medical Center, van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands; Department of Molecular Microbiology, Institute of Molecular Cell Biology, VU University, de Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Zhou P, Xie J. Comparative genomics of the Mycobacterium signaling architecture and implications for a novel live attenuated Tuberculosis vaccine. Hum Vaccin Immunother 2013; 10:159-63. [PMID: 24013364 DOI: 10.4161/hv.26268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Tuberculosis (TB), caused by Mycobacterium tuberculosis (M.tb), remains a major threat to global public health. A new TB vaccine affording superior immune protection to M. bovis Bacillus Calmette-Guérin (BCG) is imperative. The advantage of a live attenuated vaccine is that it can mimic the bona fide pathogen, elicit immune responses similar to natural infection, and potentially provide more protection than other vaccines. BCG, the only vaccine and a live attenuated vaccine that is the result of cumulative mutations by serial passage of M. bovis, has provided clues for the construction of novel improved vaccines. A strategy is put forward for identifying a new live attenuated TB vaccine generated by cumulative mutation based on M.tb. Given the important role of the M.tb signaling network consisting of a two-component system, eukaryotic-like Ser/Thr protein kinase system and sigma factor system based on comparisons among M.tb H37Rv, M. bovis, and BCG, we have put a premium on this signaling circuit as the starting point for the generation of an attenuated TB vaccine.
Collapse
Affiliation(s)
- Peifu Zhou
- Institute of Modern Biopharmaceuticals; State Key Laboratory breeding Breeding base Base of Three Gorges Eco-environment and Bioresources; Eco-Environment Key Laboratory of the Three Gorges Reservoir Region; Ministry of Education; School of Life Sciences; Southwest University; Chongqing, PR China; College of Chemistry & Environmental Science; Guizhou Minzu University; Guiyang, PR China
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals; State Key Laboratory breeding Breeding base Base of Three Gorges Eco-environment and Bioresources; Eco-Environment Key Laboratory of the Three Gorges Reservoir Region; Ministry of Education; School of Life Sciences; Southwest University; Chongqing, PR China
| |
Collapse
|
32
|
Immunogenicity and safety of the vaccinia virus LC16m8Δ vector expressing SIV Gag under a strong or moderate promoter in a recombinant BCG prime-recombinant vaccinia virus boost protocol. Vaccine 2013; 31:3549-57. [DOI: 10.1016/j.vaccine.2013.05.071] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Revised: 03/23/2013] [Accepted: 05/17/2013] [Indexed: 01/13/2023]
|
33
|
Jensen K, Pena MGD, Wilson RL, Ranganathan UDK, Jacobs WR, Fennelly G, Larsen M, Van Rompay KKA, Kozlowski PA, Abel K. A neonatal oral Mycobacterium tuberculosis-SIV prime / intramuscular MVA-SIV boost combination vaccine induces both SIV and Mtb-specific immune responses in infant macaques. ACTA ACUST UNITED AC 2013; 2:53-63. [PMID: 24454591 DOI: 10.1016/j.trivac.2013.09.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Mother-to-child-transmission of HIV by breast-feeding remains a major obstacle in the eradication of HIV infection. Compared to adults, HIV-infected infants have more rapid disease and show higher susceptibility to co-infections like tuberculosis (TB). Although the Bacille Calmette-Guérin vaccine can be administered at birth to protect against TB, BCG can disseminate in HIV-infected infants and increase mortality. Thus, a pediatric combination vaccine to stop both HIV and TB infection in infants is urgently needed. Towards the goal of developing a pediatric combination HIV-TB vaccine to prevent both oral HIV acquisition by breast-feeding and TB infection, we tested and optimized an immunization regimen using a novel live attenuated Mycobacterium tuberculosis vaccine engineered to express simian immunodeficiency (SIV) antigens followed by heterologous MVA-SIV boosting in the infant macaque model. A single oral dose of the attenuated Mtb-SIV vaccine strain mc26435 during the first week of life was sufficient to induce persistent TB-specific immune responses. SIV-specific immunity was induced at low but comparable magnitudes after oral or intradermal priming, and was enhanced following MVA-SIV boosts. T cell responses were most pronounced in intestinal tissues and oral lymph nodes. Importantly, in addition to plasma SIV-specific IgG and IgA antibodies, infant macaques developed mucosal SIV-specific IgA in saliva and intestinal IgA and IgG. While future SIV and Mtb challenge studies will be needed to determine the protective efficacy of the Mtb-SIV / MVA-SIV vaccine, infants at high risk for oral HIV acquisition by breast-feeding and TB infection could profoundly benefit from an effective combination vaccine.
Collapse
Affiliation(s)
- Kara Jensen
- Department of Microbiology and Immunology, and Center for AIDS Research, School of Medicine, University of North Carolina at Chapel Hill, NC, United States
| | - Myra Grace Dela Pena
- Department of Microbiology and Immunology, and Center for AIDS Research, School of Medicine, University of North Carolina at Chapel Hill, NC, United States
| | - Robert L Wilson
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA
| | | | | | - Glenn Fennelly
- Albert Einstein College of Medicine, New York, United States
| | - Michelle Larsen
- Albert Einstein College of Medicine, New York, United States
| | - Koen K A Van Rompay
- California National Primate Research Center, University of California at Davis, CA, United States
| | - Pamela A Kozlowski
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA
| | - Kristina Abel
- Department of Microbiology and Immunology, and Center for AIDS Research, School of Medicine, University of North Carolina at Chapel Hill, NC, United States
| |
Collapse
|
34
|
van der Woude AD, Luirink J, Bitter W. Getting across the cell envelope: mycobacterial protein secretion. Curr Top Microbiol Immunol 2012; 374:109-34. [PMID: 23239236 DOI: 10.1007/82_2012_298] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Protein secretion is an essential determinant of mycobacterial virulence. Mycobacterium tuberculosis has a unique cell envelope consisting of two lipid bilayers, which requires dedicated protein secretion pathways. The conserved general Sec and Tat translocation systems are responsible for protein transport across the inner membrane and are both essential. Additionally, the accessory Sec pathway specifically contributes to virulence. How transport of Sec/Tat substrates across the outer membrane is accomplished is currently an enigma. In addition to these pathways, M. tuberculosis also developed specialized secretion systems for protein transport across both membranes, the type VII or ESX secretion systems. Here, we discuss our current knowledge about the mechanisms and substrates of these different protein translocation systems and their role in mycobacterial physiology and virulence.
Collapse
Affiliation(s)
- Aniek D van der Woude
- Department of Molecular Microbiology, Institute of Molecular Cell Biology, VU University, Amsterdam, The Netherlands
| | | | | |
Collapse
|