Biology subjects

Simons, N. D.

Publications and source records attributed to Simons, N. D..

4 recordsLinked to original sources

bioRxiv2026

Adaptive immune responses to vaccination reflect social status at first exposure in female rhesus macaques

Social gradients are consistently associated with variation in health outcomes, including infectious disease. However, distinguishing between social gradients in antigen exposure versus social gradients in susceptibility remains challenging. Here, we use a nonhuman primate model for chronic social stress to investigate how social status affects the influenza vaccine-induced adaptive immune response. We first manipulated the social status of female rhesus macaques and then tested the response to influenza antigens in naive individuals and after secondary exposure. Higher social status at the time of first exposure, but not at the time of secondary exposure, predicted stronger antibody responses to both exposures. Social status also drove gene expression differences in adaptive immune pathways, and genes that predicted the magnitude of the antibody response overlapped with those linked to social status. Thus, social gradients shape the adaptive immune response in a temporally dependent manner, with particular sensitivity at the time of initial antigen exposure.

genomics↗

bioRxiv2021

Agonism and grooming behavior explain social status effects on physiology and gene regulation in rhesus macaques

Variation in social status predicts molecular, physiological, and life history outcomes across a broad range of species, including our own. Experimental studies indicate that some of these relationships persist even when the physical environment is held constant. Here, we draw on data sets from one such study--experimental manipulation of dominance rank in captive female rhesus macaques--to investigate how social status shapes the lived experience of these animals to alter gene regulation, glucocorticoid physiology, and mitochondrial DNA phenotypes. We focus specifically on dominance rank-associated dimensions of the social environment, including both competitive and affiliative interactions. Our results show that simple summaries of rank-associated behavioral interactions are often better predictors of molecular and physiological outcomes than dominance rank itself. However, while measures of immune function are best explained by agonism rates, glucocorticoid-related phenotypes tend to be more closely linked to affiliative behavior. We conclude that dominance rank serves as a useful summary for investigating social environmental effects on downstream outcomes. Nevertheless, the behavioral interactions that define an individuals daily experiences reveal the proximate drivers of social status-related differences, and are especially relevant for understanding why individuals who share the same social status sometimes appear physiologically distinct.

genomics↗

bioRxiv2019

Genomic and transcriptomic evidence for descent from Plasmodium and loss of blood schizogony in Hepatocystis parasites from naturally infected red colobus monkeys

Hepatocystis is a genus of single-celled parasites infecting monkeys, bats and squirrels. Although thought to descend from malaria parasites (Plasmodium spp.), Hepatocystis spp. are thought not to undergo replication in the blood - the part of the Plasmodium life cycle which causes the symptoms of malaria. Furthermore, Hepatocystis is transmitted by midges, not mosquitoes. Comparative genomics of Hepatocystis and Plasmodium species therefore presents an opportunity to better understand some of the most important aspects of malaria parasite biology. We were able to generate a draft genome for Hepatocystis using DNA sequencing reads from the blood of a naturally infected red colobus monkey. We provide robust phylogenetic support for Hepatocystis as a sister group to Plasmodium parasites infecting rodents. We show transcriptomic support for a lack of replication in the blood and genomic support for a complete loss of a family of genes involved in red blood cell invasion. Our analyses highlight the rapid evolution of genes involved in parasite vector stages, revealing genes that may be critical for interactions between malaria parasites and mosquitoes.

genomics↗

bioRxiv2019

Social history and exposure to pathogen signals modulate social status effects on gene regulation in rhesus macaques

Social experiences are an important predictor of disease susceptibility and survival in humans and other social mammals. Chronic social stress is thought to generate a pro-inflammatory state characterized by elevated antibacterial defenses and reduced investment in antiviral defense. Here, we manipulated long-term social status in female rhesus macaques to show that social subordination alters the gene expression response to ex vivo bacterial and viral challenge. As predicted by current models, bacterial lipopolysaccharide polarizes the immune response such that low status corresponds to higher expression of genes in NF-{kappa}B-dependent pro-inflammatory pathways and lower expression of genes involved in the antiviral response and type I interferon (IFN) signaling. Counter to predictions, however, low status drives more exaggerated expression of both NF-{kappa}B and IFN-associated genes after cells are exposed to the viral mimic Gardiquimod. Status-driven gene expression patterns are not only linked to social status at the time of sampling, but also to social history (i.e., past social status), especially in unstimulated cells. However, for a subset of genes, we observed interaction effects in which females who fell in rank were more strongly affected by current social status than those who climbed the social hierarchy. Together, our results indicate that the effects of social status on immune cell gene expression depend on pathogen exposure, pathogen type, and social history - in support of social experience-mediated biological embedding in adulthood, even in the conventionally memory-less innate immune system.

genomics↗