Adjuvant modulation of the cytokine balance in Mycobacterium tuberculosis subunit vaccines; immunity, pathology and protection

Immunology. 2008 Jun;124(2):175-85. doi: 10.1111/j.1365-2567.2007.02751.x. Epub 2008 Jan 12.

Abstract

It is known that protection against tuberculosis is mediated primarily by T helper type 1 (Th1) cells but the influence of the Th1/Th2 balance of a vaccination response on the subsequent protection and pathology during infection has not been studied in detail. We designed a panel of Ag85B-ESAT-6 subunit vaccines based on adjuvants with different Th1/Th2-promoting activities and studied cellular responses, bacterial replication and pathology in the lungs of mice infected with Mycobacterium tuberculosis. All vaccines induced cell-mediated and humoral responses but with markedly different interferon-gamma : interleukin-5 (IFN-gamma : IL-5) and immunoglobulin G1 (IgG1) : IgG2 ratios. The vaccines promoted different levels of control of bacterial replication with the most efficient protection being exerted by cationic liposomes containing monophosphoryl lipid A and low to completely absent immunity with conventional aluminium. The level of protection correlated with the amount of IFN-gamma produced in response to the vaccine whereas there was no inverse correlation with the level of IL-5. Characterizing a protective response was an accelerated recruitment of IL-17 and IFN-gamma-producing lymphocytes resulting in the early formation of granulomas containing clustered inducible nitric oxide synthase-activated macrophages. In comparison, non-protected mice exhibited a different inflammatory infiltrate rich in neutrophil granulocytes. This study indicates that the adjuvant component of a tuberculosis vaccine may be crucial in determining the kinetics by which effective granulomas, pivotal in controlling bacterial growth, are formed.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic
  • Animals
  • Cells, Cultured
  • Female
  • Granuloma / immunology
  • Granuloma / microbiology
  • Immunization / methods
  • Interferon-gamma / biosynthesis
  • Lung / immunology
  • Lung / microbiology
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mycobacterium tuberculosis / immunology
  • Mycobacterium tuberculosis / isolation & purification
  • Th1 Cells / immunology
  • Th2 Cells / immunology
  • Tuberculosis Vaccines / immunology*
  • Tuberculosis, Pulmonary / immunology
  • Tuberculosis, Pulmonary / microbiology
  • Tuberculosis, Pulmonary / pathology
  • Tuberculosis, Pulmonary / prevention & control*
  • Vaccines, Subunit / immunology

Substances

  • Adjuvants, Immunologic
  • Tuberculosis Vaccines
  • Vaccines, Subunit
  • Interferon-gamma