1. Cell mediated immune responses following revaccination with an influenza A/H5N1 vaccine.
- Author
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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, and Keitel WA
- Subjects
- Adjuvants, Immunologic administration & dosage, Adult, Age Factors, Aged, Cytokines immunology, Female, Granzymes immunology, Humans, Influenza A Virus, H5N1 Subtype, Interferon-gamma immunology, Leukocytes, Mononuclear immunology, Male, Middle Aged, Vaccines, Inactivated administration & dosage, Vaccines, Inactivated therapeutic use, Young Adult, Immunity, Cellular, Immunization, Secondary, Influenza Vaccines administration & dosage, Influenza Vaccines therapeutic use, Influenza, Human prevention & control
- 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., 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., 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., Conclusion: CMI responses occur in adults administered influenza A/H5N1 inactivated influenza vaccine., (Copyright © 2015 Elsevier Ltd. All rights reserved.)
- Published
- 2016
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