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Evaluation of early innate and adaptive immune responses to the TB vaccine Mycobacterium bovis BCG and vaccine candidate BCGΔBCG1419c. Sci Rep 2022; 12:12377. [PMID: 35858977 PMCID: PMC9300728 DOI: 10.1038/s41598-022-14935-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 05/03/2022] [Indexed: 12/30/2022] Open
Abstract
The vaccine Mycobacterium bovis Bacillus Calmette-Guérin (BCG) elicits an immune response that is protective against certain forms of tuberculosis (TB); however, because BCG efficacy is limited it is important to identify alternative TB vaccine candidates. Recently, the BCG deletion mutant and vaccine candidate BCGΔBCG1419c was demonstrated to survive longer in intravenously infected BALB/c mice due to enhanced biofilm formation, and better protected both BALB/c and C57BL/6 mice against TB-induced lung pathology during chronic stages of infection, relative to BCG controls. BCGΔBCG1419c-elicited protection also associated with lower levels of proinflammatory cytokines (i.e. IL6, TNFα) at the site of infection in C57BL/6 mice. Given the distinct immune profiles of BCG- and BCGΔBCG1419c-immunized mice during chronic TB, we set out to determine if there are early immunological events which distinguish these two groups, using multi-dimensional flow cytometric analysis of the lungs and other tissues soon after immunization. Our results demonstrate a number of innate and adaptive response differences between BCG- and BCGΔBCG1419c-immunized mice which are consistent with the latter being longer lasting and potentially less inflammatory, including lower frequencies of exhausted CD4+ T helper (TH) cells and higher frequencies of IL10-producing T cells, respectively. These studies suggest the use of BCGΔBCG1419c may be advantageous as an alternative TB vaccine candidate.
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Riaz MS, Kaur A, Shwayat SN, Behboudi S, Kishore U, Pathan AA. Dissecting the Mechanism of Intracellular Mycobacterium smegmatis Growth Inhibition by Platelet Activating Factor C-16. Front Microbiol 2020; 11:1046. [PMID: 32587578 PMCID: PMC7297918 DOI: 10.3389/fmicb.2020.01046] [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: 09/27/2019] [Accepted: 04/27/2020] [Indexed: 11/15/2022] Open
Abstract
Mycobacterium tuberculosis (M.tb) infection results in approximately 1.3 million human deaths each year. M.tb resides primarily inside macrophages, and maintains persistent infection. In response to infection and inflammation, platelet activating factor C-16 (PAF C-16), a phospholipid compound, is released by various cells including neutophils and monocytes. We have recently shown that PAF C-16 can directly inhibit the growth of two representative non-pathogenic mycobacteria, Mycobacterium bovis BCG and Mycobacterium smegmatis (M. smegmatis), by damaging the bacterial cell membrane. Here, we have examined the effect of PAF C-16 on M. smegmatis residing within macrophages, and identified mechanisms involved in their growth inhibitory function. Our results demonstrated that exogenous PAF C-16 inhibited the growth of M. smegmatis inside phagocytic cells of monocytic cell line, THP-1; this effect was partially blocked by PAF receptor antagonists, suggesting the involvement of PAF receptor-mediated signaling pathways. Arachidonic acid, a downstream metabolite of PAF C-16 signaling pathway, directly inhibited the growth of M. smegmatis in vitro. Moreover, the inhibition of phospholipase C and phospholipase A2 activities, involved in PAF C-16 signaling pathway, increased survival of intracellular M. smegmatis. Interestingly, we also observed that inhibition of inducible nitric oxide synthase (iNOS) enzyme and antibody-mediated neutralization of TNF-α partially mitigated the intracellular growth inhibitory effect of PAF C-16. Use of a number of PAF C-16 structural analogs, including Lyso-PAF, 2-O-methyl PAF, PAF C-18 and Hexanolamino PAF, revealed that the presence of acetyl group (CH3CO) at sn-2 position of the glycerol backbone of PAF is important for the intracellular growth inhibition activity against M. smegmatis. Taken together, these results suggest that exogenous PAF C-16 treatment inhibits intracellular M. smegmatis growth, at least partially, in a nitric oxide and TNF-α dependent manner.
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Affiliation(s)
- Muhammad Suleman Riaz
- Division of Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, United Kingdom.,Department of Biotechnology, Abdul Wali Khan University, Mardan, Pakistan
| | - Anuvinder Kaur
- Division of Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Suha Nadim Shwayat
- Division of Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Shahriar Behboudi
- The Pirbright Institute, Woking, United Kingdom.,School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Uday Kishore
- Division of Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Ansar Ahmed Pathan
- Division of Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, United Kingdom
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Rana A, Thakur S, Kumar G, Akhter Y. Recent Trends in System-Scale Integrative Approaches for Discovering Protective Antigens Against Mycobacterial Pathogens. Front Genet 2018; 9:572. [PMID: 30538722 PMCID: PMC6277634 DOI: 10.3389/fgene.2018.00572] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 11/06/2018] [Indexed: 11/21/2022] Open
Abstract
Mycobacterial infections are one of the deadliest infectious diseases still posing a major health burden worldwide. The battle against these pathogens needs to focus on novel approaches and key interventions. In recent times, availability of genome scale data has revolutionized the fields of computational biology and immunoproteomics. Here, we summarize the cutting-edge ‘omics’ technologies and innovative system scale strategies exploited to mine the available data. These may be targeted using high-throughput technologies to expedite the identification of novel antigenic candidates for the rational next generation vaccines and serodiagnostic development against mycobacterial pathogens for which traditional methods have been failing.
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Affiliation(s)
- Aarti Rana
- School of Life Sciences, Central University of Himachal Pradesh, Shahpur, India
| | - Shweta Thakur
- School of Life Sciences, Central University of Himachal Pradesh, Shahpur, India
| | - Girish Kumar
- School of Life Sciences, Central University of Himachal Pradesh, Shahpur, India
| | - Yusuf Akhter
- Department of Biotechnology, Babasaheb Bhimrao Ambedkar University, Lucknow, India
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Riaz MS, Kaur A, Shwayat SN, Behboudi S, Kishore U, Pathan AA. Direct Growth Inhibitory Effect of Platelet Activating Factor C-16 and Its Structural Analogs on Mycobacteria. Front Microbiol 2018; 9:1903. [PMID: 30258409 PMCID: PMC6143801 DOI: 10.3389/fmicb.2018.01903] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 07/27/2018] [Indexed: 12/14/2022] Open
Abstract
Mycobacterium tuberculosis, the causative agent of tuberculosis, is one of the leading causes of human deaths due to a single infectious agent. M. tuberculosis infection of the host initiates a local inflammatory response, resulting in the production of a range of inflammatory factors at the site of infection. These inflammatory factors may come in direct contact with M. tuberculosis and immune cells to activate different signaling pathways. One such factor produced in excess during inflammation is a phospholipid compound, Platelet Activating Factor C-16 (PAF C-16). In this study, PAF C-16 was shown to have a direct inhibitory effect on the growth of Mycobacterium bovis BCG (M. bovis BCG) and Mycobacterium smegmatis (M. smegmatis) in a dose- and time-dependent manner. Use of a range of PAF C-16 structural analogs, including the precursor form Lyso-PAF, revealed that small modifications in the structure of PAF C-16 did not alter its mycobacterial growth inhibitory properties. Subsequent experiments suggested that the attachment of aliphatic carbon tail via ether bond to the glycerol backbone of PAF C-16 was likely to play a vital role in its growth inhibition ability against mycobacteria. Fluorescence microscopy and flow cytometry using Propidium iodide (PI) indicated that PAF C-16 treatment had a damaging effect on the cell membrane of M. bovis BCG and M. smegmatis. Furthermore, the growth inhibitory effect of PAF C-16 was partially mitigated by treatment with membrane-stabilizing agents, α-tocopherol and Tween-80, which further suggests that the growth inhibitory effect of PAF C-16 was mediated through bacterial cell membrane damage.
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Affiliation(s)
- Muhammad S Riaz
- College of Health and Life Sciences, Division of Biosciences, Brunel University London, Uxbridge, United Kingdom.,Department of Biotechnology, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Anuvinder Kaur
- College of Health and Life Sciences, Division of Biosciences, Brunel University London, Uxbridge, United Kingdom
| | - Suha N Shwayat
- College of Health and Life Sciences, Division of Biosciences, Brunel University London, Uxbridge, United Kingdom
| | - Shahriar Behboudi
- The Pirbright Institute, Pirbright, United Kingdom.,Faculty of Health and Medical Sciences, School of Veterinary Medicine, University of Surrey, Guildford, United Kingdom
| | - Uday Kishore
- College of Health and Life Sciences, Division of Biosciences, Brunel University London, Uxbridge, United Kingdom
| | - Ansar A Pathan
- College of Health and Life Sciences, Division of Biosciences, Brunel University London, Uxbridge, United Kingdom
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Abstract
INTRODUCTION Tuberculosis (TB) is an infectious disease caused mainly by Mycobacterium tuberculosis. In 2016, the WHO estimated 10.5 million new cases and 1.8 million deaths, making this disease the leading cause of death by an infectious agent. The current and projected TB situation necessitates the development of new vaccines with improved attributes compared to the traditional BCG method. Areas covered: In this review, the authors describe the most promising candidate vaccines against TB and discuss additional key elements in vaccine development, such as animal models, new adjuvants and immunization routes and new strategies for the identification of candidate vaccines. Expert opinion: At present, around 13 candidate vaccines for TB are in the clinical phase of evaluation; however, there is still no substitute for the BCG vaccine. One major impediment to developing an effective vaccine is our lack of understanding of several of the mechanisms associated with infection and the immune response against TB. However, the recent implementation of an entirely new set of technological advances will facilitate the proposal of new candidates. Finally, development of a new vaccine will require a major coordination of effort in order to achieve its effective administration to the people most in need of it.
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Lahey T, Laddy D, Hill K, Schaeffer J, Hogg A, Keeble J, Dagg B, Ho MM, Arbeit RD, von Reyn CF. Immunogenicity and Protective Efficacy of the DAR-901 Booster Vaccine in a Murine Model of Tuberculosis. PLoS One 2016; 11:e0168521. [PMID: 27997597 PMCID: PMC5173179 DOI: 10.1371/journal.pone.0168521] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 12/02/2016] [Indexed: 12/20/2022] Open
Abstract
Background The development of a novel tuberculosis vaccine is a leading global health priority. SRL172, an inactivated, whole-cell mycobacterial vaccine, was safe, immunogenic and reduced the incidence of culture-confirmed tuberculosis in a phase III trial in HIV-infected and BCG immunized adults in Tanzania. Here we describe the immunogenicity and protective efficacy of DAR-901, a booster vaccine against tuberculosis manufactured from the same seed strain using a new scalable method. Methods We evaluated IFN-γ responses by ELISpot and antibody responses by enzyme linked immunosorbent assay in C57BL/6 and BALB/c mice after three doses of DAR-901. In an aerosol challenge model, we evaluated the protective efficacy of the DAR-901 booster in C57BL/6 mice primed with BCG and boosted with two doses of DAR-901 at 4 dosage levels in comparison with homologous BCG boost. Results DAR-901 vaccination elicited IFN-γ responses to mycobacterial antigen preparations derived from both DAR-901 and Mycobacterium tuberculosis. DAR-901 immunization enhanced antibody responses to DAR-901 but not Mycobacterium tuberculosis lysate or purified protein derivative. Among animals primed with BCG, boosting with DAR-901 at 1 mg provided greater protection against aerosol challenge than a homologous BCG boost (lungs P = 0.036, spleen P = 0.028). Conclusions DAR-901 induces cellular and humoral immunity and boosts protection from M. tuberculosis compared to a homologous BCG boost.
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Affiliation(s)
- Timothy Lahey
- Dartmouth’s Geisel School of Medicine, 1 Medical Center Drive, Lebanon, NH, United States of America
- * E-mail:
| | - Dominick Laddy
- Aeras, 1405 Research Blvd. Rockville, MD United States of America
| | - Krystal Hill
- Aeras, 1405 Research Blvd. Rockville, MD United States of America
| | | | - Alison Hogg
- Aeras, 1405 Research Blvd. Rockville, MD United States of America
| | - James Keeble
- Bacteriology Division, MHRA-NIBSC, South Mimms, Potters Bar, Hertfordshire, United Kingdom
| | - Belinda Dagg
- Bacteriology Division, MHRA-NIBSC, South Mimms, Potters Bar, Hertfordshire, United Kingdom
| | - Mei Mei Ho
- Bacteriology Division, MHRA-NIBSC, South Mimms, Potters Bar, Hertfordshire, United Kingdom
| | - Robert D. Arbeit
- Tufts University School of Medicine, Boston, MA United States of America
| | - C. Fordham von Reyn
- Dartmouth’s Geisel School of Medicine, 1 Medical Center Drive, Lebanon, NH, United States of America
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