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Study of the Safety and Immunogenicity of Bacille Calmette Guerin (BCG) Vaccine

NCT00654316 · Status: COMPLETED · Phase: PHASE1 · Type: INTERVENTIONAL · Enrollment: 11

Last updated 2008-04-07

No results posted yet for this study

Summary

Tuberculosis (TB) kills about three million people annually. It is estimated that one third of the world's population are latently infected with Mycobacterium tuberculosis (M.tb). Multi-drug resistant strains of M.tb, and co-infection with M.tb and HIV present major new challenges. The currently available vaccine, M. bovis BCG, is largely ineffective at protecting against adult pulmonary disease in endemic areas and it is widely agreed that a new more effective tuberculosis vaccine is a major global public health priority1. However, it may be unethical and impractical to test and deploy a vaccine strategy that does not include BCG, as BCG does confer worthwhile protection against TB meningitis and leprosy. An immunisation strategy that includes BCG is also attractive because the populations in which this vaccine candidate will need to be tested will already have been immunised with BCG.

M.tb is an intracellular organism. CD4+ Th1-type cellular responses are essential for protection and there is increasing evidence from animal and human studies that CD8+ T cells also play a protective role2. However, it has generally been difficult to induce strong cellular immune responses in humans using subunit vaccines. DNA vaccines induce both CD4+ and CD8+ T cells and thus offer a potential new approach to a TB vaccine. DNA vaccines encoding various antigens from M. tuberculosis have been evaluated in the murine model, and to date no DNA vaccine alone has been shown to be superior to BCG.

A heterologous prime-boost immunisation strategy involves giving two different vaccines, each encoding the same antigen, several weeks apart. Such regimes are extremely effective at inducing a cellular immune response. Using a DNA- prime/MVA-boost immunisation strategy induces high levels of CD8+ T cells in animal models of malaria and HIV5, and high levels of both CD4+ and CD8+ T cells in animal models of TB. BCG immunisation alone induces only CD4+ T cells in mice. A prime-boost strategy using BCG as the prime and a recombinant MVA encoding an antigen from M.tb that is also present in BCG (antigen 85A: 'MVA85A') as the boost, induces much higher levels of CD4+ T cells than BCG or MVA85A alone. In addition, this regime generates specific CD8+ T cells that are undetectable following immunisation with BCG alone.

Conditions

Interventions

BIOLOGICAL

BCG

intradermal injection of 0.1ml BCG over the deltoid muscle

Sponsors & Collaborators

  • University of Oxford

    lead OTHER

Principal Investigators

  • Helen McShane · University of Oxford

Study Design

Allocation
NON_RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Model
SINGLE_GROUP

Eligibility

Min Age
18 Years
Max Age
55 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2004-02-29
Primary Completion
2005-11-30
Completion
2005-11-30

Countries

  • United Kingdom

Study Locations

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Entities

Drugs
Diseases

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT00654316 on ClinicalTrials.gov