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J Infect Dis. 2017 May 15;215(10):1527-1535. doi: 10.1093/infdis/jix165.

Boosting of Cross-Reactive and Protection-Associated T Cells in Children After Live Attenuated Influenza Vaccination.

Author information

1
The Influenza Centre.
2
Emergency Care Clinic and.
3
K. G. Jebsen Centre for Influenza Vaccines, and.
4
Broegelmann Research Laboratory, Department of Clinical Science, University of Bergen, and.
5
Jenner Institute, University of Oxford, United Kingdom.
6
Department of Research & Development, Haukeland University Hospital, Bergen, Norway ; and.

Abstract

Background:

Live attenuated influenza vaccines (LAIVs) stimulate a multifaceted immune response including cellular immunity, which may provide protection against newly emerging strains. This study shows proof of concept that LAIVs boost preexisting, cross-reactive T cells in children to genetically diverse influenza A virus (IAV) strains to which the children had not been exposed.

Methods:

We studied the long-term cross-reactive T-cell response in 14 trivalent LAIV-vaccinated children using the fluorescent immunospot assay (FluoroSpot) with heterologous H1N1 and H3N2 IAVs and CD8+ peptides from the internal proteins (matrix protein 1 [M1], nucleoprotein [NP], polymerase basic protein 1 [PB1]). Serum antibody responses were determined by means of hemagglutination inhibition assay. Blood samples were collected before vaccination and up to 1 year after vaccination.

Results:

Preexisting cross-reactive T cells to genetically diverse IAV strains were found in the majority of the children, which were further boosted in 50% of them after receipt of LAIV. Further analyses of these T cells showed significant increases in CD8+ T cells, mainly dominated by NP-specific responses. After vaccination with LAIV, the youngest children showed the highest increase in T-cell responses.

Conclusion:

LAIV boosts durable, cross-reactive T-cell responses in children and may have a clinically protective effect at the population level. LAIV may be a first step toward the desired universal influenza vaccine.

KEYWORDS:

Influenza; LAIV; T-cell; cellular immune response; children; cross-reactive; heterologous; protection.; vaccine

PMID:
28368530
PMCID:
PMC5461427
DOI:
10.1093/infdis/jix165
[Indexed for MEDLINE]
Free PMC Article

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