We tested antibody replies to the trivalent inactivated influenza vaccine (TIV) in 34 aged individuals (>65yrs) during the 2012/13 vaccination months. long-lasting effects within the immune system influencing B cell reactions as well as the transcriptome of peripheral blood mononuclear cells and this residual effect may augment vaccination response in individuals where the effect of the previous vaccination has not yet diminished. = 0.04, d14 = 0.01) and significantly higher post-vaccination raises in titers for H1N1 (d7, d14, = 0.02) and for H3N2 (d7, = 0.002). In addition there was a significant inverse correlation in the time interval between the two vaccine doses and complete post-vaccination antibody titers to H1N1 (d7 = 0.05, d14 = 0.02) and titer raises after vaccination for H1N1 (d7 = 0.01, d14 = 0.004) and H3N2 (d7 = 0.008). Number 1 Graphs display VNA titers before and after vaccination in cohorts 1 and 2 To ensure that the improved response of cohort 1 was not biased by small numbers of cohort 2 or by additional intrinsic variations that allowed cohort 1 to mount better than average responses we tested additional samples gathered in the 2011/12, 2013/14 and 2014/15 months from people of cohort 1 aswell of from people of cohort 2 while others that enrolled in JWS to the research (cohort 3). We compared VNA titer increases to H1N1 at day 14 after TIV over baseline of cohort 1 to those of cohorts 2 and 3, data for the two latter cohorts were combined. In addition we assessed responsiveness by determining the percentage of individuals that mounted a response to H1N1 CCT239065 using the above-described criteria. In 2014/15 too few individuals of cohort 1 enrolled to conduct this comparison. VNA titers of cohort 1 in all other seasons such as 2011/12 and 2013/14 when they were vaccinated on the regular time schedule were indistinguishable from those of other aged individuals. Responsiveness, which on average over the 4 year period was at 59% (excluding cohort 1 2012/13 samples) tended to be lower in the other seasons in cohort 1 than in individuals of the other cohorts. This argues against increased responses of cohort 1 upon a shortened vaccination interval due to some fundamental characteristics that allowed this group of individuals to mount superior antibody responses (Figure ?(Figure2).2). In neither cohort, responsiveness in one year was predictive of responsiveness to subsequent vaccinations. Figure 2 Graph on the left shows increases of VNA titers to H1N1 between d0 and 14 after vaccination for the cohorts tested in different seasons Gene expression and early revaccination To further understand the basis for the vaccine response differences between cohorts 1 and 2 in the 2012/13 season, we performed gene expression CCT239065 arrays on whole blood collected prior to vaccination on day 0 and compared gene expression profiles between cohorts 1 and 2. We identified a significant differential expression of 786 genes (FDR<15%). A heat map for expression of the top 25 most increased and decreased genes in subjects of cohorts 1 and 2 is shown in Figure ?Figure3.3. A full list of differentially expressed genes is shown in Suppl. Table 1. Several of the transcripts that were increased in cohort 1 are involved in translation (RPL3, RPL10A, RPL38, SFRS6), protein processing and secretion (PPIL3, ITM2A, GOLGA88, SRP72, USP24), metabolism (SC5DL, DENNDAC, ADM2, ATP5H, FAM54A) or lymphocyte stimulation (CD28, ICOS). Genes that were more highly expressed in aged individuals from cohort 2, encode proteins involved in lymphocyte adhesion, mobility and migration (DIP2A, TSPA14, AHAP13, P704P. ILK, LSP1, BIN2), Ca+ flux (ORAI2, ORAI3) and innate immunity (RNF135, MARCO). Figure 3 The Figure shows as a heatmap the top 50 genes that are differentially expressed between cohort 1 and 2 Results of Ingenuity Pathway Analysis (Table ?(Table2)2) showed highly significant differences between aged CCT239065 cohorts 1.