Sex-Specific Differences of Humoral Immunity and Transcriptome Diversification in Older Adults Vaccinated with Inactivated Quadrivalent Influenza Vaccines

Clinical data showed sex variability in the immune response to influenza vaccination, this study aimed to investigate differentially expressed genes that contribute to sex-bias immune responses to quadrivalent inactivated influenza vaccines (QIVs) in older subjects. A cohort of 60 healthy older adults aged 60 to 80 years old were vaccinated with quadrivalent inactivated influenza vaccines (QIVs), and gene expression was analyzed at Day 0 pre-vaccination, Day 3, Day 28 and Day 180 post-vaccination. Sexual dimorphism of humoral immunity was analyzed by HAI assay, and the correlation of gene expression patterns of two sex groups with humoral immune response to vaccination was analyzed. The differentially expressed genes involved in type I interferon signaling pathway and complement activation of classical pathway were upregulated within 3 days post-vaccination in females. At Day 28 after immunization, the immune response showed a man-bias pattern associated with the regulation of protein processing and complement activation of classical pathway. A list of differentially expressed genes associated with variant responses to influenza vaccination between women and men were identified by biology-driven clustering. Old women have a greater immune response to QIVs but rapid decline of antibody levels, while old men have the advantages to sustain a durable response to influenza vaccination. In addition, we identified genes that may contribute to the sex variations toward influenza vaccination in the aged. Our findings highlight the importance of developing personalized seasonal influenza vaccines.