Project description:Seasonal influenza contributes to a substantial disease burden annually, resulting in approximately 10 million hospital visits and 50 thousand deaths in a typical year in the US. 90% of the annual mortality from influenza occurs in people over the age of 65. While influenza vaccination is the best protection against the virus, it is less effective for the elderly. This may be due to differences in the quantity or type of B cells induced by vaccination in older individuals. To investigate this possibility, we leveraged recent development in single-cell technology that allows for simultaneous measurement of both gene expression profile and the B cell receptor (BCR) at single-cell resolution. Pre- and post-vaccination peripheral blood B cells were sorted from three young and three older adults who responded to the inactivated influenza vaccine and were profiled using single-cell RNAseq with paired BCR sequencing. At pre-vaccination, we observed a higher somatic hypermutation frequency and a higher abundance of activated B cells in older adults than in young adults. Following vaccination, young adults mounted a more clonal response than older adults. The response involved a mix of plasmablasts, activated B cells, and resting memory B cells in both age groups. The response in young adults was dominated by expansion in plasmablasts, while the response in older adults also involved activated B cells. We observed a consistent change in gene expression in plasmablasts after vaccination between age groups but not in the activated B cells. These quantitative and qualitative differences in the B cell response may provide insights into the age-related change of influenza vaccination response.
Project description:Seasonal influenza contributes to a substantial disease burden annually, resulting in approximately 10 million hospital visits and 50 thousand deaths in a typical year in the US. 90% of the annual mortality from influenza occurs in people over the age of 65. While influenza vaccination is the best protection against the virus, it is less effective for the elderly. This may be due to differences in the quantity or type of B cells induced by vaccination in older individuals. To investigate this possibility, we leveraged recent development in single-cell technology that allows for simultaneous measurement of both gene expression profile and the B cell receptor (BCR) at single-cell resolution. Pre- and post-vaccination peripheral blood B cells were sorted from three young and three older adults who responded to the inactivated influenza vaccine and were profiled using single-cell RNAseq with paired BCR sequencing. At pre-vaccination, we observed a higher somatic hypermutation frequency and a higher abundance of activated B cells in older adults than in young adults. Following vaccination, young adults mounted a more clonal response than older adults. The response involved a mix of plasmablasts, activated B cells, and resting memory B cells in both age groups. The response in young adults was dominated by expansion in plasmablasts, while the response in older adults also involved activated B cells. We observed a consistent change in gene expression in plasmablasts after vaccination between age groups but not in the activated B cells. These quantitative and qualitative differences in the B cell response may provide insights into the age-related change of influenza vaccination response.
Project description:Influenza imparts an age-related increase in mortality and morbidity. The most effective countermeasure is vaccination; however, vaccines offer modest protection in older adults. To investigate how ageing impacts the memory B cell response we tracked haemagglutinin specific B cells by indexed flow sorting and single cell RNA sequencing in twenty healthy adults administered the trivalent influenza vaccine. We found age-related skewing in the memory B cell compartment six weeks after vaccination, with younger adults developing haemagglutinin specific memory B cells with an FCRL5+ “atypical” phenotype, showing evidence of somatic hypermutation and positive selection, which happened to a lesser extent in older persons. We confirmed the germinal center ancestry of these FCRL5+ “atypical” memory B cells using scRNASeq from fine needle aspirates of influenza responding human lymph nodes and paired blood samples. Together, this study shows that the aged human germinal center reaction and memory B cell response following vaccination is defective.
Project description: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.
Project description:This study aimed to investigate the effects of a multidomain intervention on gene expression profile of older adults with cognitive frailty in Selangor, Malaysia, using mRNA gene sequencing. The intervention included a combination of dietary changes, exercise, and psychosocial support. By analyzing gene expression profile in both groups, this study explores how multidomain interventions may influence mrna in older adults. The findings could provide insights into the role of lifestyle factors on the CF in aging populations.
Project description:Streptococcus pneumoniae colonization in the upper respiratory tract is linked to pneumococcal disease development, predominantly affecting young children and older adults. As the global population ages and comorbidities increase, there is a heightened concern about this infection. We investigated the immunological responses of older adults to pneumococcal controlled human infection by analysing the cellular composition and gene expression in the nasal mucosa. Our comparative analysis with data from a concurrent study in younger adults revealed distinct gene expression patterns in older individuals susceptible to colonization, highlighted by neutrophil activation and elevated levels of CXCL9 and CXCL10. Unlike younger adults challenged with pneumococcus, older adults did not show recruitment of monocytes into the nasal mucosa following nasal colonization. However, older adults who were protected from colonization showed increased degranulation of CD8+ T cells, both before and after pneumococcal challenge. These findings suggest age-associated cellular changes, in particular enhanced mucosal inflammation, that may predispose older adults to pneumococcal colonization.
Project description:Human neonates and older adults frequently exhibit a reduced capacity to control microbial infections. A variety of mechanisms involving both the innate and adaptive immune systems have been proposed to contribute to these deficiencies. The emergence of RNA sequencing (RNA-seq) as an accurate and quantitative method for examining mRNA levels provides an opportunity to compare transcriptional responses to a stimulus at a global scale in neonates, adults, and older adults. An examination of ex vivo monocyte responses to lipopolysaccharide stimulation or Listeria monocytogenes infection (with cord blood monocytes representing neonatal monocytes) revealed extensive similarities between all three age groups, with only a small number of genes exhibiting statistically significant differences. Using transcription factor motif analyses and RNA-seq data sets from a variety of mouse mutants, the most significant neonatal deficiencies corresponded to genes that require interferon response factor-3 or type 1 interferon signaling for their activation. In older adults, the most striking difference was broad, low-level activation of inflammatory genes prior to stimulation, consistent with prior evidence of a chronic inflammatory state in older adults. These results demonstrate the value of quantitative RNA-seq analyses and the feasibility of cross-species comparisons between well-defined mouse networks and human data sets.
Project description:Physical frailty's impact on hemagglutination inhibition antibody titers (HAI) and peripheral blood mononuclear cell (PBMC) transcriptional responses after influenza vaccination is unclear. Physical frailty was assessed using the 5-item Fried frailty phenotype in 168 community- and assisted-living adults ≥55 years of age during an observational study. Blood was drawn before, 3, 7, and 28 days post-vaccination with the 2017-2018 inactivated influenza vaccine. HAI response to the A/H1N1 strain was measured at Days 0 and 28 using seropositivity, seroconversion, log2 HAI titers, and fold-rise in log2 HAI titers. RNA sequencing of PBMCs from Days 0, 3 and 7 was measured in 28 participants and compared using pathway analyses. Frailty was not significantly associated with any HAI outcome in multivariable models. Compared with non-frail participants, frail participants expressed decreased cell proliferation, metabolism, antibody production, and interferon signaling genes. Conversely, frail participants showed elevated gene expression in IL-8 signaling, T-cell exhaustion, and oxidative stress pathways compared with non-frail participants. These results suggest that reduced effectiveness of influenza vaccine among older, frail individuals may be attributed to immunosenescence-related changes in PBMCs that are not reflected in antibody levels.
Project description:Pneumococcal infections cause serious illness and death among older adults. A capsular polysaccharide vaccine PPSV23 (Pneumovax®) and a conjugated polysaccharide vaccine PCV13 (Prevnar®) are used to prevent these infections, yet underlying immunological responses, and baseline predictors remain unknown. We recruited and vaccinated 39 older adults (>60 years) with PPSV23 or PCV13. Both vaccines induced strong antibody responses at day 28 and similar plasmablast transcriptional signatures at day 10, however, their baseline predictors were distinct. Analyses of baseline flow cytometry and RNA-seq data (bulk and single cell) revealed a novel baseline phenotype that is specifically associated with weaker PCV13 responses, characterized by i) increased expression of cytotoxicity-associated genes and increased CD16+ NK frequency; ii) increased Th17 and decreased Th1 cell frequency. Men were more likely to display this cytotoxic phenotype and mounted weaker responses to PCV13 than women. Baseline expression levels of a distinct gene set was predictive of PPSV23 responses. This first precision vaccinology study for pneumococcal vaccine responses of older adults uncovered novel and distinct baseline predictors that might transform vaccination strategies and initiate novel interventions.
Project description:Pneumococcal infections cause serious illness and death among older adults. A capsular polysaccharide vaccine PPSV23 (Pneumovax®) and a conjugated polysaccharide vaccine PCV13 (Prevnar®) are used to prevent these infections, yet underlying immunological responses, and baseline predictors remain unknown. We recruited and vaccinated 39 older adults (>60 years) with PPSV23 or PCV13. Both vaccines induced strong antibody responses at day 28 and similar plasmablast transcriptional signatures at day 10, however, their baseline predictors were distinct. Analyses of baseline flow cytometry and RNA-seq data (bulk and single cell) revealed a novel baseline phenotype that is specifically associated with weaker PCV13 responses, characterized by i) increased expression of cytotoxicity-associated genes and increased CD16+ NK frequency; ii) increased Th17 and decreased Th1 cell frequency. Men were more likely to display this cytotoxic phenotype and mounted weaker responses to PCV13 than women. Baseline expression levels of a distinct gene set was predictive of PPSV23 responses. This first precision vaccinology study for pneumococcal vaccine responses of older adults uncovered novel and distinct baseline predictors that might transform vaccination strategies and initiate novel interventions.