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Cell mediated immune responses following revaccination with an influenza A/H5N1 vaccine.

Authors :
Mbawuike IN
Atmar RL
Patel SM
Corry DB
Winokur PL
Brady RC
Chen WH
Edwards KM
Creech CB
Walter EB Jr
Frey SE
Belshe RB
Goll JB
Hill H
Keitel WA
Source :
Vaccine [Vaccine] 2016 Jan 20; Vol. 34 (4), pp. 547-554. Date of Electronic Publication: 2015 Dec 04.
Publication Year :
2016

Abstract

Purpose: The study aims were to determine whether inactivated influenza A/H5N1 vaccine administration elicited cell mediated immune (CMI) responses and the impact of adjuvant, vaccine dose and subject age on these responses.<br />Methods: Adults who were previously primed with either adjuvanted or unadjuvanted, inactivated, A/H5N1/Vietnam/1203/2004 (Clade 1) vaccine or unprimed (received placebo) in previous vaccine studies were randomized to receive one (primed) or two (unprimed) 15- or 90-mcg doses of inactivated, A/H5N1/Indonesia/05/05 (Clade 2) vaccine. Peripheral blood mononuclear cells (PBMCs) were collected and analyzed from a subset of vaccinees to assess CMI responses using IFN-γ and granzyme B ELISPOT assays. Cytokine measurements were performed on PBMC supernatants after stimulation with H5N1 virus.<br />Results: PBMCs were available from 177 participants; 88 and 89 received 15-mcg and 90-mcg of unadjuvanted clade 2 vaccine, respectively. Following H5N1 clade 1 stimulation, IFN-γ but not granzyme B normalized spot-forming cell numbers had statistically significant increased numbers at each of the post-vaccination timepoints compared to baseline in pooled analyses of all vaccine doses and age groups. Clade 2 stimulation resulted in statistically significant increased numbers of IFN-γ cells only 180 days following the last vaccination. Responses were similar among younger and older study participants, as were responses among those primed with alum-adjuvanted or non-adjuvanted clade 1 H5N1 vaccines. The dosage of clade 2 vaccine did not impact CMI responses among primed subjects, but responses were statistically significantly greater in unprimed recipients of the 90-mcg dosage compared to unprimed recipients of the 15-mcg dosage. IFN-γ levels in the supernatants of stimulated PBMC were strongly correlated with IFN-γ ELISPOT results.<br />Conclusion: CMI responses occur in adults administered influenza A/H5N1 inactivated influenza vaccine.<br /> (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Details

Language :
English
ISSN :
1873-2518
Volume :
34
Issue :
4
Database :
MEDLINE
Journal :
Vaccine
Publication Type :
Academic Journal
Accession number :
26657997
Full Text :
https://doi.org/10.1016/j.vaccine.2015.11.055