AUTHOR=Voigt Emily A. , Ovsyannikova Inna G. , Kennedy Richard B. , Grill Diane E. , Goergen Krista M. , Schaid Daniel J. , Poland Gregory A. 

TITLE=Sex Differences in Older Adults' Immune Responses to Seasonal Influenza Vaccination

JOURNAL=Frontiers in Immunology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2019.00180

DOI=10.3389/fimmu.2019.00180

ISSN=1664-3224

ABSTRACT=<p><bold>Background:</bold> Sex differences in immune responses to influenza vaccine may impact efficacy across populations.</p><p><bold>Methods:</bold> In a cohort of 138 older adults (50–74 years old), we measured influenza A/H1N1 antibody titers, B-cell ELISPOT response, PBMC transcriptomics, and PBMC cell compositions at 0, 3, and 28 days post-immunization with the 2010/11 seasonal inactivated influenza vaccine.</p><p><bold>Results:</bold> We identified higher B-cell ELISPOT responses in females than males. Potential mechanisms for sex effects were identified in four gene clusters related to T, NK, and B cells. Mediation analysis indicated that sex-dependent expression in T and NK cell genes can be partially attributed to higher CD4+ T cell and lower NK cell fractions in females. We identified strong sex effects in 135 B cell genes whose expression correlates with ELISPOT measures, and found that cell subset differences did not explain the effect of sex on these genes' expression. Post-vaccination expression of these genes, however, mediated 41% of the sex effect on ELISPOT responses.</p><p><bold>Conclusions:</bold> These results improve our understanding of sexual dimorphism in immunity and influenza vaccine response.</p>