Longevity and determinants of protective humoral immunity after pandemic influenza infection

Sridhar, S., Begom, S., Hoschler, K., Bermingham, A., Adamson, W., Carman, W., Riley, S. and Lalvani, A. (2015) Longevity and determinants of protective humoral immunity after pandemic influenza infection. American Journal of Respiratory and Critical Care Medicine, 191(3), pp. 325-332. (doi: 10.1164/rccm.201410-1798OC) (PMID:25506631) (PMCID:PMC4351579)

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Abstract

Rationale: Antibodies to influenza hemagglutinin are the primary correlate of protection against infection. The strength and persistence of this immune response influences viral evolution and consequently the nature of influenza epidemics. However, the durability and immune determinants of induction of humoral immunity after primary influenza infection remain unclear. Objectives: The spread of a novel H1N1 (A[H1N1]pdm09) virus in 2009 through an unexposed population offered a natural experiment to assess the nature and longevity of humoral immunity after a single primary influenza infection. Methods: We followed A(H1N1)pdm09-seronegative adults through two influenza seasons (2009–2011) as they developed A(H1N1)pdm09 influenza infection or were vaccinated. Antibodies to A(H1N1)pdm09 virus were measured by hemagglutination-inhibition assay in individuals with paired serum samples collected preinfection and postinfection or vaccination to assess durability of humoral immunity. Preexisting A(H1N1)pdm09-specific multicytokine-secreting CD4 and CD8 T cells were quantified by multiparameter flow cytometry to test the hypothesis that higher frequencies of CD4+ T-cell responses predict stronger antibody induction after infection or vaccination. Measurements and Main Results: Antibodies induced by natural infection persisted at constant high titer for a minimum of approximately 15 months. Contrary to our initial hypothesis, the fold increase in A(H1N1)pdm09-specific antibody titer after infection was inversely correlated to the frequency of preexisting circulating A(H1N1)pdm09-specific CD4+IL-2+IFN-γ−TNF-α− T cells (r = −0.4122; P = 0.03). Conclusions: The longevity of protective humoral immunity after influenza infection has important implications for influenza transmission dynamics and vaccination policy, and identification of its predictive cellular immune correlate could guide vaccine development and evaluation.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Adamson, Dr Walt
Authors: Sridhar, S., Begom, S., Hoschler, K., Bermingham, A., Adamson, W., Carman, W., Riley, S., and Lalvani, A.
College/School:College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
Journal Name:American Journal of Respiratory and Critical Care Medicine
Publisher:American Thoracic Society
ISSN:1073-449X
ISSN (Online):1535-4970
Published Online:15 December 2014

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