Predominance of heterosubtypic IFN-γ-only-secreting effector memory T cells in pandemic H1N1 naive adults.
Eur J Immunol
; 42(11): 2913-24, 2012 Nov.
Article
em En
| MEDLINE
| ID: mdl-22777887
ABSTRACT
The 2009/10 pandemic (pH1N1) highlighted the need for vaccines conferring heterosubtypic immunity against antigenically shifted influenza strains. Although cross-reactive T cells are strong candidates for mediating heterosubtypic immunity, little is known about the population-level prevalence, frequency, and cytokine-secretion profile of heterosubtypic T cells to pH1N1. To assess this, pH1N1 sero-negative adults were recruited. Single-cell IFN-γ and IL-2 cytokine-secretion profiles to internal proteins of pH1N1 or live virus were enumerated and characterised. Heterosubtypic T cells recognising pH1N1 core proteins were widely prevalent, being detected in 90% (30 of 33) of pH1N1-naïve individuals. Although the last exposure to influenza was greater than 6 months ago, the frequency and proportion of the IFN-γ-only-secreting T-cell subset was significantly higher than the IL-2-only-secreting subset. CD8(+) IFN-γ-only-secreting heterosubtypic T cells were predominantly CCR7(-) CD45RA(-) effector-memory phenotype, expressing the tissue-homing receptor CXCR3 and degranulation marker CD107. Receipt of the 2008-09 influenza vaccine did not alter the frequency of these heterosubtypic T cells, highlighting the inability of current vaccines to maintain this heterosubtypic T-cell pool. The surprisingly high prevalence of pre-existing circulating pH1N1-specific CD8(+) IFN-γ-only-secreting effector memory T cells with cytotoxic and lung-homing potential in pH1N1-seronegative adults may partly explain the low case fatality rate despite high rates of infection of the pandemic in young adults.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Interferon gama
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Linfócitos T CD8-Positivos
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Influenza Humana
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Vírus da Influenza A Subtipo H1N1
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Pandemias
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Memória Imunológica
Tipo de estudo:
Etiology_studies
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Incidence_studies
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Observational_studies
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Prevalence_studies
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Risk_factors_studies
Limite:
Adolescent
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Adult
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Aged
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Humans
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Middle aged
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article