Half-truths and selective memory: Interferon gamma, CD4(+) T cells and protective memory against tuberculosis.
Efforts to develop a new, more effective vaccine for tuberculosis have been hampered by a lack of understanding of what constitutes a protective memory immune response. While interferon gamma production by CD4(+) T cells after vaccination is commonly used as a surrogate of protective memory immunity, its use in this regard appears to have little predictive value. We argue that this is due to the different requirements for interferon gamma-mediated protection in the primary response versus the memory recall response. In this review, we present evidence that suggests memory CD4(+) T cells can protect against tuberculosis in the absence of interferon gamma, and discuss potential mechanisms that may be involved such as IL-17 and regulatory T cells. A comprehensive understanding of the requirements for protective memory immunity to tuberculosis is essential for the development of an effective vaccine.
Goldsack
Lisa
L
Malaghan Institute of Medical Research, P.O. Box 7060, Wellington South 6021, New Zealand.
Kirman
Joanna R
JR
D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory; D007371:Interferon-gamma / Q000276:immunology*; D020381:Interleukin-17 / Q000096:biosynthesis; D018417:Th1 Cells / Q000276:immunology; D014376:Tuberculosis / Q000276:immunology / Q000517:prevention & control*; D032581:Tuberculosis Vaccines / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
D020381:Interleukin-17; D032581:Tuberculosis Vaccines; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma