Social Experiences and Demographic Factors in the Regulation of Immune Cells

More than a third of the residents of the United States suffer from a chronic disease, with almost half involving dysregulated immune processes. Immune-mediated inflammatory diseases pose a public health burden in the United States. Preliminary data from previous work suggest that variations in ethnic identity and geography might influence discrimination experiences and inflammatory response trends. To investigate the functional implications of these findings, a multi-institutional study is proposed, examining how social experiences and demographic factors predict the regulation and activity of immune cells. Specifically, the hypothesis is that geography, self-identified race, and ethnicity, interacting with laboratory discrimination conditions, significantly affect immune cell function through genomic and epigenetic mechanisms, with perceived discrimination moderating the immune outcomes. Participants will provide saliva samples, complete psychosocial and demographic questionnaires, and play the virtual social exclusion game Cyberball™ in a randomly assigned block order. Acute discrimination experiences are manipulated by conditions during Cyberball. Virtual players, who appear to be of a different race from the participant, exclude them by not passing the participant the ball in the race-based exclusion condition. In the inclusion condition, the participant receives the ball regardless of participant and virtual player race. In the general social exclusion (not race-based), the players and participant races are similar to the inclusion condition, except that the participant does not receive the ball. The block of Cyberball and blood draws randomly assigned are either: 1) race-based social exclusion and inclusion first, a blood draw, then non-race-based social exclusion, inclusion, and blood draw, or 2) non-race-based social exclusion and inclusion, a blood draw and then the race-based social exclusion and inclusion and a blood draw. Baseline and post-first block inflammatory responses in saliva will be measured using enzyme-linked immunosorbent assays (ELISAs) to determine the concentration of cytokines like C-reactive protein, interleukin-6, and tumor necrosis factor-alpha. Flow cytometry and immune cell stimulation with toxin will test monocytes purified and sorted from the participant's blood for functional effects. Next-generation transcriptomics and epigenomics will assess differentially expressed RNA and methylation enrichment, emphasizing genes involved in inflammation signaling pathways. The data will be statistically analyzed using regression analysis and structural equation modeling to determine the relationship between discrimination, geography, immune cell function, and regulation while controlling for other socio-demographic factors. The findings could inform public health initiatives and interventions to reduce health disparities and improve outcomes for marginalized communities.