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Painter H, Willcocks S, Zelmer A, Reljic R, Tanner R, Fletcher H. Demonstrating the utility of the ex vivo murine mycobacterial growth inhibition assay (MGIA) for high-throughput screening of tuberculosis vaccine candidates against multiple Mycobacterium tuberculosis complex strains. Tuberculosis (Edinb) 2024; 146:102494. [PMID: 38367368 DOI: 10.1016/j.tube.2024.102494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/05/2024] [Accepted: 02/11/2024] [Indexed: 02/19/2024]
Abstract
Human tuberculosis (TB) is caused by various members of the Mycobacterium tuberculosis (Mtb) complex. Differences in host response to infection have been reported, illustrative of a need to evaluate efficacy of novel vaccine candidates against multiple strains in preclinical studies. We previously showed that the murine lung and spleen direct mycobacterial growth inhibition assay (MGIA) can be used to assess control of ex vivo mycobacterial growth by host cells. The number of mice required for the assay is significantly lower than in vivo studies, facilitating testing of multiple strains and/or the incorporation of other cellular analyses. Here, we provide proof-of-concept that the murine MGIA can be applied to evaluate vaccine-induced protection against multiple Mtb clinical isolates. Using an ancient and modern strain of the Mtb complex, we demonstrate that ex vivo bacillus Calmette-Guérin (BCG)-mediated mycobacterial growth inhibition recapitulates protection observed in the lung and spleen following in vivo infection of mice. Further, we provide the first report of cellular and transcriptional correlates of BCG-induced growth inhibition in the lung MGIA. The ex vivo MGIA represents a promising platform to gain early insight into vaccine performance against a collection of Mtb strains and improve preclinical evaluation of TB vaccine candidates.
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Affiliation(s)
- Hannah Painter
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
| | - Sam Willcocks
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Andrea Zelmer
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Rajko Reljic
- Institute of Infection and Immunity, St George's University of London, Cranmer Terrrace, London, SW17 0RE, UK
| | - Rachel Tanner
- Department of Biology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Helen Fletcher
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
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Painter H, Harriss E, Fletcher HA, McShane H, Tanner R. Development and application of the direct mycobacterial growth inhibition assay: a systematic review. Front Immunol 2024; 15:1355983. [PMID: 38380319 PMCID: PMC10877019 DOI: 10.3389/fimmu.2024.1355983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 01/17/2024] [Indexed: 02/22/2024] Open
Abstract
Introduction First described by Wallis et al. in 2001 for the assessment of TB drugs, the direct mycobacterial growth inhibition assay (MGIA) offers a tractable ex vivo tool measuring the combined influences of host immunity, strain virulence and intervention effects. Over the past 13 years, we have led efforts to adapt the direct MGIA for the assessment of TB vaccines including optimisation, harmonisation and validation of BCG vaccine-induced responses as a benchmark, as well as assay transfer to institutes worldwide. Methods We have performed a systematic review on the primary published literature describing the development and applications of the direct MGIA from 2001 to June 2023 in accordance with the PRISMA reporting guidelines. Results We describe 63 studies in which the direct MGIA has been applied across species for the evaluation of TB drugs and novel TB vaccine candidates, the study of clinical cohorts including those with comorbidities, and to further understanding of potential immune correlates of protection from TB. We provide a comprehensive update on progress of the assay since its conception and critically evaluate current findings and evidence supporting its utility, highlighting priorities for future directions. Discussion While further standardisation and validation work is required, significant advancements have been made in the past two decades. The direct MGIA provides a potentially valuable tool for the early evaluation of TB drug and vaccine candidates, clinical cohorts, and immune mechanisms of mycobacterial control. Systematic review registration https://www.crd.york.ac.uk/prospero/, identifier CRD42023423491.
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Affiliation(s)
- Hannah Painter
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Eli Harriss
- Bodleian Health Care Libraries, University of Oxford, Oxford, United Kingdom
| | - Helen A. Fletcher
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Helen McShane
- Nuffield Department of Medicine, Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Rachel Tanner
- Department of Biology, University of Oxford, Oxford, United Kingdom
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Wang R, Fan X, Xu D, Li M, Zhao X, Cao B, Qian C, Yu J, Fang D, Gu Y, Wan K, Liu H. Comparison of the Immunogenicity and Efficacy of rBCG-EPCP009, BCG Prime-EPCP009 Booster, and EPCP009 Protein Regimens as Tuberculosis Vaccine Candidates. Vaccines (Basel) 2023; 11:1738. [PMID: 38140143 PMCID: PMC10747267 DOI: 10.3390/vaccines11121738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 11/04/2023] [Accepted: 11/15/2023] [Indexed: 12/24/2023] Open
Abstract
Bacillus Calmette-Guérin (BCG) is the only widely used prophylactic tuberculosis (TB) vaccine that can prevent severe TB in infants. However, it provides poor protection in adults, and therefore, there is ongoing research into new TB vaccines and immunization strategies with more durable immune effects. The recombinant BCG and BCG prime-protein booster are two important vaccine strategies that have recently been developed based on BCG and could improve immune responses. In this study, three immune strategies based on four protective antigens, namely, ESAT-6, CFP-10, nPPE18, and nPstS1, were applied to construct recombinant rBCG-EPCP009, EPCP009 subunit protein, and BCG prime-EPCP009 booster vaccine candidates. The short- and long-term immune effects after vaccination in Balb/c mice were evaluated based on humoral immunity, cellular immunity, and the ability of spleen cells to inhibit in vitro mycobacterial growth. At 8 and 12 weeks after the initial immunization, splenocytes from mice inoculated with the BCG prime-EPCP009 protein booster secreted higher levels of PPD- and EPCP009-specific IFN-γ, IL-2, TNF-α, IL-17, GM-CSF, and IL-12 and had a higher IFN-γ+CD4+ TEM:IL-2+CD8+ TCM cell ratio than splenocytes from mice inoculated with the rBCG-EPCP009 and EPCP009 proteins. In addition, the EPCPE009-specific IgG2a/IgG1 ratio was slightly higher in the BCG prime-EPCP009 protein booster group than in the other two groups. The in vitro mycobacterial inhibition assay showed that the splenocytes of mice from the BCG prime-EPCP009 protein booster group exhibited stronger inhibition of Mycobacterium tuberculosis (M. tuberculosis) growth than the splenocytes of mice from the other two groups. These results indicate that the BCG prime-EPCP009 protein booster exhibited superior immunogenicity and M. tuberculosis growth inhibition to the parental BCG, rBCG-EPCP009, and EPCP009 proteins under in vitro conditions. Thus, the BCG prime-EPCP009 protein booster may be important for the development of a more effective adult TB vaccine.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Kanglin Wan
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China; (R.W.); (X.F.); (D.X.); (M.L.); (X.Z.); (B.C.); (C.Q.); (J.Y.); (D.F.); (Y.G.)
| | - Haican Liu
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China; (R.W.); (X.F.); (D.X.); (M.L.); (X.Z.); (B.C.); (C.Q.); (J.Y.); (D.F.); (Y.G.)
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Tanner R, Hoogkamer E, Bitencourt J, White A, Boot C, Sombroek CC, Harris SA, O'Shea MK, Wright D, Wittenberg R, Sarfas C, Satti I, Verreck FA, Sharpe SA, Fletcher HA, McShane H. The in vitro direct mycobacterial growth inhibition assay (MGIA) for the early evaluation of TB vaccine candidates and assessment of protective immunity: a protocol for non-human primate cells. F1000Res 2021; 10:257. [PMID: 33976866 PMCID: PMC8097740 DOI: 10.12688/f1000research.51640.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/17/2021] [Indexed: 04/04/2024] Open
Abstract
The only currently available approach to early efficacy testing of tuberculosis (TB) vaccine candidates is in vivo preclinical challenge models. These typically include mice, guinea pigs and non-human primates (NHPs), which must be exposed to virulent M.tb in a 'challenge' experiment following vaccination in order to evaluate protective efficacy. This procedure results in disease development and is classified as 'Moderate' in severity under EU legislation and UK ASPA licensure. Furthermore, experiments are relatively long and animals must be maintained in high containment level facilities, making them relatively costly. We describe an in vitro protocol for the direct mycobacterial growth inhibition assay (MGIA) for use in the macaque model of TB vaccine development with the aim of overcoming some of these limitations. Importantly, using an in vitro assay in place of in vivo M.tb challenge represents a significant refinement to the existing procedure for early vaccine efficacy testing. Peripheral blood mononuclear cell and autologous serum samples collected from vaccinated and unvaccinated control animals are co-cultured with mycobacteria in a 48-well plate format for 96 hours. Adherent monocytes are then lysed to release intracellular mycobacteria which is quantified using the BACTEC MGIT system and colony-forming units determined relative to an inoculum control and stock standard curve. We discuss related optimisation and characterisation experiments, and review evidence that the direct NHP MGIA provides a biologically relevant model of vaccine-induced protection. The potential end-users of the NHP MGIA are academic and industry organisations that conduct the assessment of TB vaccine candidates and associated protective immunity using the NHP model. This approach aims to provide a method for high-throughput down-selection of vaccine candidates going forward to in vivo efficacy testing, thus expediting the development of a more efficacious TB vaccine and offering potential refinement and reduction to the use of NHPs for this purpose.
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Affiliation(s)
- Rachel Tanner
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
| | - Emily Hoogkamer
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
- Public Health England, Salisbury, SP4 0JG, UK
| | - Julia Bitencourt
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
- Gonҫalo Moniz Institute, Oswaldo Cruz Foundation (FIOCRUZ), Salvador, 40296-710, Brazil
| | | | - Charelle Boot
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, 2288 GJ, The Netherlands
| | - Claudia C. Sombroek
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, 2288 GJ, The Netherlands
| | | | - Matthew K. O'Shea
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
- Institute of Immunology and Immunotherapy, University of Birmingham, UK, Birmingham, B15 2TH, UK
| | - Daniel Wright
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
| | - Rachel Wittenberg
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
| | | | - Iman Satti
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
| | - Frank A.W. Verreck
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, 2288 GJ, The Netherlands
| | | | - Helen A. Fletcher
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
- London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Helen McShane
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
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5
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Tanner R, Hoogkamer E, Bitencourt J, White A, Boot C, Sombroek CC, Harris SA, O'Shea MK, Wright D, Wittenberg R, Sarfas C, Satti I, Verreck FAW, Sharpe SA, Fletcher HA, McShane H. The in vitro direct mycobacterial growth inhibition assay (MGIA) for the early evaluation of TB vaccine candidates and assessment of protective immunity: a protocol for non-human primate cells. F1000Res 2021; 10:257. [PMID: 33976866 PMCID: PMC8097740.2 DOI: 10.12688/f1000research.51640.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/15/2021] [Indexed: 11/29/2022] Open
Abstract
The only currently available approach to early efficacy testing of tuberculosis (TB) vaccine candidates is in vivo preclinical challenge models. These typically include mice, guinea pigs and non-human primates (NHPs), which must be exposed to virulent M.tb in a 'challenge' experiment following vaccination in order to evaluate protective efficacy. This procedure results in disease development and is classified as 'Moderate' in severity under EU legislation and UK ASPA licensure. Furthermore, experiments are relatively long and animals must be maintained in high containment level facilities, making them relatively costly. We describe an in vitro protocol for the direct mycobacterial growth inhibition assay (MGIA) for use in the macaque model of TB vaccine development with the aim of overcoming some of these limitations. Importantly, using an in vitro assay in place of in vivo M.tb challenge represents a significant refinement to the existing procedure for early vaccine efficacy testing. Peripheral blood mononuclear cell and autologous serum samples collected from vaccinated and unvaccinated control animals are co-cultured with mycobacteria in a 48-well plate format for 96 hours. Adherent monocytes are then lysed to release intracellular mycobacteria which is quantified using the BACTEC MGIT system and colony-forming units determined relative to an inoculum control and stock standard curve. We discuss related optimisation and characterisation experiments, and review evidence that the direct NHP MGIA provides a biologically relevant model of vaccine-induced protection. The potential end-users of the NHP MGIA are academic and industry organisations that conduct the assessment of TB vaccine candidates and associated protective immunity using the NHP model. This approach aims to provide a method for high-throughput down-selection of vaccine candidates going forward to in vivo efficacy testing, thus expediting the development of a more efficacious TB vaccine and offering potential refinement and reduction to the use of NHPs for this purpose.
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Affiliation(s)
- Rachel Tanner
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
| | - Emily Hoogkamer
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
- Public Health England, Salisbury, SP4 0JG, UK
| | - Julia Bitencourt
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
- Gonҫalo Moniz Institute, Oswaldo Cruz Foundation (FIOCRUZ), Salvador, 40296-710, Brazil
| | | | - Charelle Boot
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, 2288 GJ, The Netherlands
| | - Claudia C Sombroek
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, 2288 GJ, The Netherlands
| | - Stephanie A Harris
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
| | - Matthew K O'Shea
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
- Institute of Immunology and Immunotherapy, University of Birmingham, UK, Birmingham, B15 2TH, UK
| | - Daniel Wright
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
| | - Rachel Wittenberg
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
| | | | - Iman Satti
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
| | - Frank A W Verreck
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, 2288 GJ, The Netherlands
| | | | - Helen A Fletcher
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
- London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Helen McShane
- Nuffield Department of Medicine, The Jenner Institute, Oxford, OX3 7DQ, UK
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Tanner R, White AD, Boot C, Sombroek CC, O'Shea MK, Wright D, Hoogkamer E, Bitencourt J, Harris SA, Sarfas C, Wittenberg R, Satti I, Fletcher HA, Verreck FAW, Sharpe SA, McShane H. A non-human primate in vitro functional assay for the early evaluation of TB vaccine candidates. NPJ Vaccines 2021; 6:3. [PMID: 33397986 DOI: 10.1038/s41541-020-00263-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 11/23/2020] [Indexed: 01/29/2023] Open
Abstract
We present a non-human primate mycobacterial growth inhibition assay (MGIA) using in vitro blood or cell co-culture with the aim of refining and expediting early tuberculosis vaccine testing. We have taken steps to optimise the assay using cryopreserved peripheral blood mononuclear cells, transfer it to end-user institutes, and assess technical and biological validity. Increasing cell concentration or mycobacterial input and co-culturing in static 48-well plates compared with rotating tubes improved intra-assay repeatability and sensitivity. Standardisation and harmonisation efforts resulted in high consistency agreements, with repeatability and intermediate precision <10% coefficient of variation (CV) and inter-site reproducibility <20% CV; although some systematic differences were observed. As proof-of-concept, we demonstrated ability to detect a BCG vaccine-induced improvement in growth inhibition in macaque samples, and a correlation between MGIA outcome and measures of protection from in vivo disease development following challenge with either intradermal BCG or aerosol/endobronchial Mycobacterium tuberculosis (M.tb) at a group and individual animal level.
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Painter H, Prabowo SA, Cia F, Stockdale L, Tanner R, Willcocks S, Reljic R, Fletcher HA, Zelmer A. Adaption of the ex vivo mycobacterial growth inhibition assay for use with murine lung cells. Sci Rep 2020; 10:3311. [PMID: 32094451 PMCID: PMC7039920 DOI: 10.1038/s41598-020-60223-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 01/31/2020] [Indexed: 11/19/2022] Open
Abstract
In the absence of a correlate(s) of protection against human tuberculosis and a validated animal model of the disease, tools to facilitate vaccine development must be identified. We present an optimised ex vivo mycobacterial growth inhibition assay (MGIA) to assess the ability of host cells within the lung to inhibit mycobacterial growth, including Bacille Calmette-Guérin (BCG) and Mycobacterium tuberculosis (MTB) Erdman. Growth of BCG was reduced by 0.39, 0.96 and 0.73 log10 CFU following subcutaneous (s.c.) BCG, intranasal (i.n.) BCG, or BCG s.c. + mucosal boost, respectively, versus naïve mice. Comparatively, a 0.49 (s.c.), 0.60 (i.n.) and 0.81 (s.c. + mucosal boost) log10 reduction in MTB CFU was found. A BCG growth inhibitor, 2-thiophenecarboxylic acid hydrazide (TCH), was used to prevent quantification of residual BCG from i.n. immunisation and allow accurate MTB quantification. Using TCH, a further 0.58 log10 reduction in MTB CFU was revealed in the i.n. group. In combination with existing methods, the ex vivo lung MGIA may represent an important tool for analysis of vaccine efficacy and the immune mechanisms associated with vaccination in the organ primarily affected by MTB disease.
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Affiliation(s)
- Hannah Painter
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
| | - Satria A Prabowo
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Felipe Cia
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Lisa Stockdale
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
- Oxford Vaccine Group, Department of Paediatrics, NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, OX4 2PG, UK
| | - Rachel Tanner
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Samuel Willcocks
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Rajko Reljic
- Institute of Infection and Immunity, St George's University of London, Cranmer Terrrace, London, SW17 0RE, UK
| | - Helen A Fletcher
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Andrea Zelmer
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
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Tanner R, Smith SG, van Meijgaarden KE, Giannoni F, Wilkie M, Gabriele L, Palma C, Dockrell HM, Ottenhoff THM, McShane H. Optimisation, harmonisation and standardisation of the direct mycobacterial growth inhibition assay using cryopreserved human peripheral blood mononuclear cells. J Immunol Methods 2019; 469:1-10. [PMID: 30710562 DOI: 10.1016/j.jim.2019.01.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 12/13/2018] [Accepted: 01/15/2019] [Indexed: 11/21/2022]
Abstract
A major challenge to tuberculosis (TB) vaccine development is the lack of a validated immune correlate of protection. Mycobacterial growth inhibition assays (MGIAs) represent an unbiased measure of the ability to control mycobacterial growth in vitro. A successful MGIA could be applied to preclinical and clinical post-vaccination samples to aid in the selection of novel vaccine candidates at an early stage and provide a relevant measure of immunogenicity and protection. However, assay harmonisation is critical to ensure that comparable information can be extracted from different vaccine studies. As part of the FP7 European Research Infrastructures for Poverty Related Diseases (EURIPRED) consortium, we aimed to optimise the direct MGIA, assess repeatability and reproducibility, and harmonise the assay across different laboratories. We observed an improvement in repeatability with increased cell number and increased mycobacterial input. Furthermore, we determined that co-culturing in static 48-well plates compared with rotating 2 ml tubes resulted in a 23% increase in cell viability and a 500-fold increase in interferon-gamma (IFN-γ) production on average, as well as improved reproducibility between replicates, assay runs and sites. Applying the optimised conditions, we report repeatability to be <5% coefficient of variation (CV), intermediate precision to be <20% CV, and inter-site reproducibility to be <30% CV; levels within acceptable limits for a functional cell-based assay. Using relevant clinical samples, we demonstrated comparable results across two shared sample sets at three sites. Based on these findings, we have established a standardised operating procedure (SOP) for the use of the direct PBMC MGIA in TB vaccine development.
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Joosten SA, van Meijgaarden KE, Arend SM, Prins C, Oftung F, Korsvold GE, Kik SV, Arts RJ, van Crevel R, Netea MG, Ottenhoff TH. Mycobacterial growth inhibition is associated with trained innate immunity. J Clin Invest 2018; 128:1837-1851. [PMID: 29461976 DOI: 10.1172/jci97508] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 02/13/2018] [Indexed: 12/29/2022] Open
Abstract
The lack of defined correlates of protection hampers development of vaccines against tuberculosis (TB). In vitro mycobacterial outgrowth assays are thought to better capture the complexity of the human host/Mycobacterium tuberculosis (Mtb) interaction. Here, we used a mycobacterial growth inhibition assay (MGIA) based on peripheral blood mononuclear cells to investigate the capacity to control outgrowth of bacille Calmette-Guérin (BCG). Interestingly, strong control of BCG outgrowth was observed almost exclusively in individuals with recent exposure to Mtb, but not in (long-term) latent TB infection, and only modestly in BCG vaccinees. Mechanistically, control of mycobacterial outgrowth strongly correlated with the presence of a CD14dim monocyte population, but also required the presence of T cells. The nonclassical monocytes produced CXCL10, and CXCR3 receptor blockade inhibited the capacity to control BCG outgrowth. Expression of CXCR3 splice variants was altered in recently Mtb-exposed individuals. Cytokines previously associated with trained immunity were detected in MGIA supernatants, and CXCL9, CXCL10, and CXCL11 represent new markers of trained immunity. These data indicate that CXCR3 ligands are associated with trained immunity and are critical factors in controlling mycobacterial outgrowth. In conclusion, control of mycobacterial outgrowth early after exposure to Mtb is the result of trained immunity mediated by a CXCL10-producing nonclassical CD14dim monocyte subset.
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Affiliation(s)
- Simone A Joosten
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands
| | | | - Sandra M Arend
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands
| | - Corine Prins
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands
| | - Fredrik Oftung
- Division of Infection Control and Environmental Health, Department of Infectious Disease Immunology, Norwegian Institute of Public Health, Oslo, Norway
| | - Gro Ellen Korsvold
- Division of Infection Control and Environmental Health, Department of Infectious Disease Immunology, Norwegian Institute of Public Health, Oslo, Norway
| | - Sandra V Kik
- KNCV Tuberculosis Foundation, The Hague, Netherlands
| | - Rob Jw Arts
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
| | - Reinout van Crevel
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
| | - Mihai G Netea
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
| | - Tom Hm Ottenhoff
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands
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Brennan MJ, Tanner R, Morris S, Scriba TJ, Achkar JM, Zelmer A, Hokey DA, Izzo A, Sharpe S, Williams A, Penn-Nicholson A, Erasmus M, Stylianou E, Hoft DF, McShane H, Fletcher HA. The Cross-Species Mycobacterial Growth Inhibition Assay (MGIA) Project, 2010-2014. Clin Vaccine Immunol 2017; 24:e00142-17. [PMID: 28701467 PMCID: PMC5585695 DOI: 10.1128/cvi.00142-17] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The development of a functional biomarker assay in the tuberculosis (TB) field would be widely recognized as a major advance in efforts to develop and to test novel TB vaccine candidates efficiently. We present preliminary studies using mycobacterial growth inhibition assays (MGIAs) to detect Mycobacterium bovis BCG vaccine responses across species, and we extend this work to determine whether a standardized MGIA can be applied in characterizing new TB vaccines. The comparative MGIA studies reviewed here aimed to evaluate robustness, reproducibility, and ability to reflect in vivo responses. In doing so, they have laid the foundation for the development of a MGIA that can be standardized and potentially qualified. A major challenge ahead lies in better understanding the relationships between in vivo protection, in vitro growth inhibition, and the immune mechanisms involved. The final outcome would be a MGIA that could be used with confidence in TB vaccine trials. We summarize data arising from this project, present a strategy to meet the goals of developing a functional assay for TB vaccine testing, and describe some of the challenges encountered in performing and transferring such assays.
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Affiliation(s)
| | - Rachel Tanner
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Sheldon Morris
- Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, USA
| | - Thomas J Scriba
- South African Tuberculosis Vaccine Initiative and Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Jacqueline M Achkar
- Departments of Medicine, Microbiology, and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Andrea Zelmer
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | - Angelo Izzo
- Colorado State University, Fort Collins, Colorado, USA
| | - Sally Sharpe
- Public Health England, Porton Down, Salisbury, United Kingdom
| | - Ann Williams
- Public Health England, Porton Down, Salisbury, United Kingdom
| | - Adam Penn-Nicholson
- South African Tuberculosis Vaccine Initiative and Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Mzwandile Erasmus
- South African Tuberculosis Vaccine Initiative and Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Elena Stylianou
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | - Helen McShane
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Helen A Fletcher
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, United Kingdom
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Jensen C, Lindebo Holm L, Svensson E, Aagaard C, Ruhwald M. Optimisation of a murine splenocyte mycobacterial growth inhibition assay using virulent Mycobacterium tuberculosis. Sci Rep 2017; 7:2830. [PMID: 28588268 PMCID: PMC5460210 DOI: 10.1038/s41598-017-02116-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 04/05/2017] [Indexed: 11/21/2022] Open
Abstract
In the absence of a validated correlate of protection or robust animal models for human tuberculosis, Mycobacterial growth inhibition assays (MGIAs) aim to assess vaccines ability to inhibit mycobacterial growth in-vitro. We optimised a reproducible murine splenocyte MGIA based on in-vitro infection with virulent Mycobacterium tuberculosis (M.tb) Erdman. We identified splenocyte viability as a problem in state-of-art MGIA protocols, which can be improved by simple changes in culture conditions (viability increase from 21% to 46% at last day of culture). The growth inhibitory potential in mice immunised with either BCG, H56:CAF01 or H56:CAF01 administered side-by-side with BCG was significantly better compared to placebo in all groups (0.3 log10 CFU [±0.2, p = 0.049], 0.5 [±0.2, p = 0.016] and 0.6 [±0.1, p = 0.0007], respectively) corresponding to the levels of in-vivo protection. Unexpectedly the CAF01 adjuvant control group also induced significant growth inhibition of 0.3 log10 CFU (±0.2, p = 0.047). Finally, we explored vaccine-associated T cell effector functions. Despite presence of high levels of vaccine-specific T cells, we found no increase in CD4+ T cell number or cytokine expression profile, nor a difference in cytokine levels in the supernatant after four days culture with or without M.tb. Spontaneous IFN-γ release correlated with growth inhibition levels (p = 0.02), however the cellular source was not found.
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Affiliation(s)
- Christina Jensen
- Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark
| | - Line Lindebo Holm
- Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark
- Copenhagen University Hospitals, Hvidovre, Copenhagen, Denmark
| | - Erik Svensson
- International Reference Laboratory of Mycobacteriology, Statens Serum Institut, Copenhagen, Denmark
| | - Claus Aagaard
- Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark
| | - Morten Ruhwald
- Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark.
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