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Abstract
The world is witnessing an escalation of the tuberculosis (TB) epidemic, particularly in sub-Saharan Africa and South-East Asia. The problem has been compounded by the evolution of the human immunodeficiency virus pandemic, the increase in multidrug-resistant TB and the emergence of extensively drug-resistant TB. This has led to renewed interest in vaccines aimed at preventing tuberculosis. The current Bacille Calmette-Guérin (BCG) vaccine prevents the invasive complications of childhood tuberculosis, such as meningitis and miliary disease, but provides variable protection against adult pulmonary disease. This review discusses the history of the BCG vaccine, the reasons for its variable efficacy, protective immunity and TB, and the evolution of and obstacles to development of new candidate vaccines. Several new TB vaccines have demonstrated promising results in animal models; a number have gone into phase I clinical trials in humans, and it is anticipated that phase III trials will commence by 2009. Licensing of an effective new TB vaccine by 2015 is thus a possibility.
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Affiliation(s)
- Gregory Hussey
- South African Tuberculosis Vaccine Initiative, University of Cape Town, Anzio Road, Observatory, 7925, South Africa.
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202
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Radosevic K, Wieland CW, Rodriguez A, Weverling GJ, Mintardjo R, Gillissen G, Vogels R, Skeiky YAW, Hone DM, Sadoff JC, van der Poll T, Havenga M, Goudsmit J. Protective immune responses to a recombinant adenovirus type 35 tuberculosis vaccine in two mouse strains: CD4 and CD8 T-cell epitope mapping and role of gamma interferon. Infect Immun 2007; 75:4105-15. [PMID: 17526747 PMCID: PMC1951991 DOI: 10.1128/iai.00004-07] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
There is an urgent need for an efficacious vaccine against tuberculosis (TB). Cellular immune responses are key to an effective protective response against TB. Recombinant adenovirus (rAd) vectors are especially suited to the induction of strong T-cell immunity and thus represent promising vaccine vehicles for the prevention of TB. We have previously reported on rAd vector serotype 35, the serotype of choice due to low preexisting immunity worldwide, which expresses a unique fusion protein of Mycobacterium tuberculosis antigens Ag85A, Ag85B, and TB10.4 (Ad35-TBS). Here, we demonstrate that Ad35-TBS confers protection against M. tuberculosis when administered to mice through either an intranasal or an intramuscular route. Histological evaluation of lung tissue corroborated the protection and, in addition, demonstrated differences between two mouse strains, with diffuse inflammation in BALB/c mice and distinct granuloma formation in C57BL/6 mice. Epitope mapping analysis in these mouse strains showed that the major T-cell epitopes are conserved in the artificial fusion protein, while three novel CD8 peptides were discovered. Using a defined set of T-cell epitopes, we reveal differences between the two mouse strains in the type of protective immune response, demonstrating that different antigen-specific gamma interferon (IFN-gamma)-producing T cells can provide protection against M. tuberculosis challenge. While in BALB/c (H-2(d)) mice, a dominant CD8 T-cell response was detected, in C57BL/6 (H-2(b)) mice, more balanced CD4/CD8 T-cell responses were observed, with a more pronounced CD4 response in the lungs. These results unify conflicting reports on the relative importance of CD4 versus CD8 T-cell responses in protection and emphasize the key role of IFN-gamma.
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MESH Headings
- Acyltransferases/genetics
- Acyltransferases/immunology
- Adenoviridae/genetics
- Administration, Intranasal
- Animals
- Antigens, Bacterial/genetics
- Antigens, Bacterial/immunology
- Bacterial Proteins/genetics
- Bacterial Proteins/immunology
- Colony Count, Microbial
- Disease Models, Animal
- Epitope Mapping
- Epitopes, T-Lymphocyte/immunology
- Female
- Genetic Vectors
- Injections, Intramuscular
- Interferon-gamma/immunology
- Liver/microbiology
- Lung/microbiology
- Lung/pathology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/immunology
- Spleen/microbiology
- Tuberculosis/prevention & control
- Tuberculosis Vaccines/genetics
- Tuberculosis Vaccines/immunology
- Vaccines, Synthetic/genetics
- Vaccines, Synthetic/immunology
- Viral Vaccines/genetics
- Viral Vaccines/immunology
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203
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Sander C, McShane H. Translational mini-review series on vaccines: Development and evaluation of improved vaccines against tuberculosis. Clin Exp Immunol 2007; 147:401-11. [PMID: 17302888 PMCID: PMC1810501 DOI: 10.1111/j.1365-2249.2006.03306.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Tuberculosis (TB) continues to be a major global health disaster, despite the widespread use of BCG and effective drug therapies. The development of an efficacious new TB vaccine would be an important component of disease control in the future. Many approaches are being utilised to enhance understanding of the requirements of a successful vaccine. Numerous vaccines are being designed and assessed in a series of animal models, with a few progressing to clinical trials. Here, the steps involved in the development and evaluation of TB vaccines will be discussed, including description of the most frequently used animal models and the processes involved in advancing vaccines to phase III trials.
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Affiliation(s)
- C Sander
- University of Oxford, CCVTM, Churchill Hospital, Oxford, UK.
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204
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Morais da Fonseca D, Lopes Silva C, Oliveira e Paula M, Garcia Soares E, Marchal G, Horn C, Deperon Bonato VL. Increased levels of interferon-gamma primed by culture filtrate proteins antigen and CpG-ODN immunization do not confer significant protection against Mycobacterium tuberculosis infection. Immunology 2007; 121:508-17. [PMID: 17433075 PMCID: PMC2265969 DOI: 10.1111/j.1365-2567.2007.02597.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The results of various animal model studies of tuberculosis (TB) suggest that culture filtrate proteins (CFPs), which are antigens secreted by Mycobacterium tuberculosis, are largely responsible for improvements in TB vaccines. The great obstacle to developing protein subunit vaccines is that adjuvants are required in order to stimulate relevant protective immune responses. Acting as immune adjuvants, CpG-oligodeoxynucleotides (CpG-ODNs) promote the activation of Th1 cells and of pro-inflammatory cytokines. To evaluate the adjuvant role of CpG-ODNs in conferring enhanced immunogenic capacity and protection against M. tuberculosis, we immunized mice with CFP antigen combined with synthetic CpG-ODNs (CFP/CpG) or with incomplete Freund's adjuvant (IFA) (CFP/IFA). Immunization with CFP/CpG induced a T helper 1 (Th1)-biased response accompanied by a higher immunoglobulin G2a (IgG2a) antibody/IgG1 antibody ratio, elevated production of interferon-gamma (IFN-gamma) by spleen cells and in lungs. However, CFP/IFA-immunized mice presented higher levels of IgG1 antibodies, as well as increased production of IFN-gamma, interleukin (IL)-5, and IL-10 by spleen cells, together with lower levels of IFN-gamma in the lungs. Despite the stronger Th1 response seen in both groups, believed to be necessary for protection against TB, only mice immunized with CFP/IFA were protected after M. tuberculosis infection. Lung histology revealed that lung parenchyma were better preserved in CFP/IFA-immunized mice, which also presented intense lymphocyte recruitment to the lesion, whereas CFP/CpG-immunized mice presented severe pulmonary injury accompanied by necrosis. Based on the data presented, we discuss the widely accepted paradigm that high levels of IFN-gamma are directly correlated with protection against experimental TB.
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Affiliation(s)
- Denise Morais da Fonseca
- Tuberculosis Research Centre, Department of Biochemistry and Immunology, Ribeirão Preto School of Medicine, University of São PauloBrazil
| | - Célio Lopes Silva
- Tuberculosis Research Centre, Department of Biochemistry and Immunology, Ribeirão Preto School of Medicine, University of São PauloBrazil
| | - Marina Oliveira e Paula
- Tuberculosis Research Centre, Department of Biochemistry and Immunology, Ribeirão Preto School of Medicine, University of São PauloBrazil
| | - Edson Garcia Soares
- Department of Pathology, Ribeirão Preto School of Medicine, University of São PauloBrazil
| | - Gilles Marchal
- Laboratoire de Référence des Mycobacteries, Institute PasteurParis, France
| | - Cynthia Horn
- FIOCRUZ, Oswaldo Cruz Institute Foundation, Rio de JaneiroBrazil
| | - Vânia Luiza Deperon Bonato
- Tuberculosis Research Centre, Department of Biochemistry and Immunology, Ribeirão Preto School of Medicine, University of São PauloBrazil
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205
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Abstract
Tuberculosis (TB) continues to kill more than 2 million people globally each year. Annual TB case notification rates have risen up to fourfold since the mid-1980s, with the highest rate of 1000/100,000 around Cape Town, South Africa. There is an urgent need for novel diagnostic methods and preventive vaccines to control this epidemic. The rising incidence of TB has been attributed to HIV co-infection especially in developing countries. The threat of drug resistance arising from ineffective TB treatment programmes is looming and could potentially lead to loss of any gains made in controlling the disease globally.
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Affiliation(s)
- D B Meya
- Infectious Disease Institute, Makerere University, Kampala, Uganda.
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206
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Cendron D, Ingoure S, Martino A, Casetti R, Horand F, Romagné F, Sicard H, Fournié JJ, Poccia F. A tuberculosis vaccine based on phosphoantigens and fusion proteins induces distinct gammadelta and alphabeta T cell responses in primates. Eur J Immunol 2007; 37:549-65. [PMID: 17230439 DOI: 10.1002/eji.200636343] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Phosphoantigens are mycobacterial non-peptide antigens that might enhance the immunogenicity of current subunit candidate vaccines for tuberculosis. However, their testing requires monkeys, the only animal models suitable for gammadelta T cell responses to mycobacteria. Thus here, the immunogenicity of 6-kDa early secretory antigenic target-mycolyl transferase complex antigen 85B (ESAT-6-Ag85B) (H-1 hybrid) fusion protein associated or not to a synthetic phosphoantigen was compared by a prime-boost regimen of two groups of eight cynomolgus. Although phosphoantigen activated immediately a strong release of systemic Th1 cytokines (IL-2, IL-6, IFN-gamma, TNF-alpha), it further anergized blood gammadelta T lymphocytes selectively. By contrast, the hybrid H-1 induced only memory alphabeta T cell responses, regardless of phosphoantigen. These latter essentially comprised cytotoxic T lymphocytes specific for Ag85B (on average + 430 cells/million PBMC) and few IFN-gamma-secreting cells (+ 40 cells/million PBMC, equally specific for ESAT-6 and for Ag85B). Hence, in macaques, a prime-boost with the H-1/phosphoantigen subunit combination induces two waves of immune responses, successively by gammadelta T and alphabeta T lymphocytes.
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Affiliation(s)
- Delphine Cendron
- Groupe d'Etude des Antigènes Non-Conventionnels, Unité 563 INSERM, Centre de Physiopathologie de Toulouse Purpan, Toulouse, France
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207
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Källenius G, Pawlowski A, Brandtzaeg P, Svenson S. Should a new tuberculosis vaccine be administered intranasally? Tuberculosis (Edinb) 2007; 87:257-66. [PMID: 17321797 DOI: 10.1016/j.tube.2006.12.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2006] [Revised: 12/14/2006] [Accepted: 12/21/2006] [Indexed: 12/22/2022]
Abstract
Most of the world's population is vaccinated with the only available vaccine against tuberculosis (TB), the Bacillus Calmette-Guérin (BCG) vaccine that was developed almost a century ago. Despite the wide coverage of the BCG vaccine, there are great variations in protective efficacy among different study populations. BCG vaccination protects against childhood forms of TB, but this immunity wanes with age, resulting in none, or insufficient, protection against adult pulmonary TB (PTB). PTB is the major disease manifestation of TB in adults and it causes death at the most productive age, further adding to poverty in already impoverished countries. Therefore, new more effective vaccines and novel immunisation strategies are urgently needed. The most common route of TB is by inhalation of tubercle bacilli leading to the establishment of a primary infection in the lung. Immunising through the nasal mucosal surface should therefore have advantage over other routes, as such vaccine administration elicits protective immune responses also in the lung, i.e. at the site of primary infection. Several new TB-vaccine candidates have been evaluated for their protective efficacy in animal models using the mucosal route of immunisation. In formulating such vaccines, the adjuvants and delivery systems are crucially important.
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Affiliation(s)
- Gunilla Källenius
- Department of Bacteriology, Swedish Institute for Infectious Disease Control, 17182 Solna, Sweden.
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208
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Sable SB, Plikaytis BB, Shinnick TM. Tuberculosis subunit vaccine development: Impact of physicochemical properties of mycobacterial test antigens. Vaccine 2007; 25:1553-66. [PMID: 17166640 DOI: 10.1016/j.vaccine.2006.11.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Revised: 09/27/2006] [Accepted: 11/07/2006] [Indexed: 11/23/2022]
Abstract
Tuberculosis caused by Mycobacterium tuberculosis continues to be one of the major public health problems in the world. The eventual control of this disease will require the development of a safe and effective vaccine. One of the approaches receiving a great deal of attention recently is subunit vaccination. An efficacious antituberculous subunit vaccine requires the identification and isolation of key components of the pathogen that are capable of inducing a protective immune response. Clues to identify promising subunit vaccine candidates may be found in their physicochemical and immunobiological properties. In this article, we review the evidence that the physicochemical properties of mycobacterial components can greatly impact the induction of either protective or deleterious immune response and consequently influence the potential utility as an antituberculous subunit vaccine.
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Affiliation(s)
- Suraj B Sable
- Division of TB Elimination, National Center for HIV, STD, and TB Prevention, Centers for Disease Control and Prevention, Mailstop G35, 1600 Clifton Road, Atlanta, GA 30333, USA
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209
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Sable SB, Kalra M, Verma I, Khuller GK. Tuberculosis subunit vaccine design: the conflict of antigenicity and immunogenicity. Clin Immunol 2007; 122:239-51. [PMID: 17208519 DOI: 10.1016/j.clim.2006.10.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Revised: 10/12/2006] [Accepted: 10/20/2006] [Indexed: 01/02/2023]
Abstract
The attempts to find an effective antituberculous subunit vaccine are based on the assumption that it must drive a Th1 response. In the absence of effective correlates of protection, a vast array of mycobacterial components are being evaluated worldwide either on the basis of their ability to be recognized by T lymphocytes in in vitro assays during early stage of animal or human infection (antigenicity) or their capacity to induce T cell response following immunization in animal models (immunogenicity). The putative vaccine candidates selected using either of these strategies are then subjected to challenge studies in different animal models to evaluate the protective efficacy. Here we review the outcome of this current scheme of selection of vaccine candidates using an 'antigenicity' or 'immunogenicity' criterion on the actual protective efficacy observed in experimental animal models. The possible implications for the success of some of the leading vaccine candidates in clinical trials will also be discussed.
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Affiliation(s)
- Suraj B Sable
- Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh-160 012, India.
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210
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Andersen P. Vaccine strategies against latent tuberculosis infection. Trends Microbiol 2006; 15:7-13. [PMID: 17141504 DOI: 10.1016/j.tim.2006.11.008] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Revised: 11/14/2006] [Accepted: 11/21/2006] [Indexed: 11/17/2022]
Abstract
The leading tuberculosis (TB) vaccines currently in clinical trials are all designed as prophylactic vaccines. Although these vaccines are highly active, they will most probably not result in sterilizing immunity and, therefore, will not solve the global problem of latent TB. An attractive strategy is to target the remaining dormant bacteria with vaccines based upon antigens induced as the bacteria change from active multiplication to non-replicating dormancy (latency antigens) or during reactivation as dormant bacteria resume active metabolism (resuscitation antigens). These late-stage antigens might have potential as post-exposure vaccines or could form the basis for a multi-stage vaccine strategy, in which they are combined with prophylactic vaccines based on early antigens from replicating bacteria.
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Affiliation(s)
- Peter Andersen
- Department of Infectious Disease Immunology, Statens Serum Institute, DK-2300 Copenhagen, Denmark.
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211
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Salerno-Gonçalves R, Sztein MB. Cell-mediated immunity and the challenges for vaccine development. Trends Microbiol 2006; 14:536-42. [PMID: 17055276 DOI: 10.1016/j.tim.2006.10.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 09/13/2006] [Accepted: 10/10/2006] [Indexed: 10/24/2022]
Abstract
One of the hallmarks of successful vaccination is the induction of strong and persistent memory T cell responses, a process that involves striking changes in the number and functional properties of T cells. Many questions pertaining to this complex, multifaceted process remain unanswered. Some of the key issues and challenges to optimize memory T cell responses and foster vaccine development include the optimization of effector T cell burst sizes, the use of adjuvants, cytokines and co-stimulatory molecules, epitope enhancement and the standardization of techniques to detect specific T cells. Age also has an impact on vaccine design because of the physiological changes in cell-mediated immunity that occur throughout life.
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Affiliation(s)
- Rosangela Salerno-Gonçalves
- Center for Vaccine Development, Department of Pediatrics, University of Maryland, 685 West Baltimore Street, HSF-1, Room 480, Baltimore, MD 21201, USA
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212
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Ibanga HB, Brookes RH, Hill PC, Owiafe PK, Fletcher HA, Lienhardt C, Hill AVS, Adegbola RA, McShane H. Early clinical trials with a new tuberculosis vaccine, MVA85A, in tuberculosis-endemic countries: issues in study design. THE LANCET. INFECTIOUS DISEASES 2006; 6:522-8. [PMID: 16870530 DOI: 10.1016/s1473-3099(06)70552-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tuberculosis remains a substantial global health problem despite effective drug treatments. The efficacy of BCG, the only available vaccine, is variable, especially in tuberculosis-endemic regions. Recent advances in the development of new vaccines against tuberculosis mean that the first of these are now entering into early clinical trials. A recombinant modified vaccinia virus Ankara expressing a major secreted antigen from Mycobacterium tuberculosis, antigen 85A, was the first new tuberculosis vaccine to enter into clinical trials in September 2002. This vaccine is known as MVA85A. In a series of phase I clinical trials in the UK, MVA85A had an excellent safety profile and was highly immunogenic. MVA85A was subsequently evaluated in a series of phase I trials in The Gambia, a tuberculosis-endemic area in west Africa. This vaccine is the only new subunit tuberculosis vaccine to enter into clinical trials in Africa to date. Here, we discuss some of the issues that were considered in the protocol design of these studies including recruitment, inclusion and exclusion criteria, reimbursement of study participants, and HIV testing. These issues are highly relevant to early clinical trials with all new tuberculosis vaccines in the developing world.
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