More Like this

1. Induced Immune Reaction in the Acorn Worm, Saccoglossus kowalevskii , Informs the Evolution of Antiviral Immunity

   https://doi.org/10.1093/molbev/msad097  

   Tassia, Michael G; Hallowell, Haley A; Waits, Damien S; Range, Ryan C; Lowe, Christopher J; Graze, Rita M; Schwartz, Elizabeth Hiltbold; Halanych, Kenneth M (May 2023, Molecular Biology and Evolution)

   Leitner, Thomas (Ed.)

   Abstract Evolutionary perspectives on the deployment of immune factors following infection have been shaped by studies on a limited number of biomedical model systems with a heavy emphasis on vertebrate species. Although their contributions to contemporary immunology cannot be understated, a broader phylogenetic perspective is needed to understand the evolution of immune systems across Metazoa. In our study, we leverage differential gene expression analyses to identify genes implicated in the antiviral immune response of the acorn worm hemichordate, Saccoglossus kowalevskii, and place them in the context of immunity evolution within deuterostomes—the animal clade composed of chordates, hemichordates, and echinoderms. Following acute exposure to the synthetic viral double-stranded RNA analog, poly(I:C), we show that S. kowalevskii responds by regulating the transcription of genes associated with canonical innate immunity signaling pathways (e.g., nuclear factor κB and interferon regulatory factor signaling) and metabolic processes (e.g., lipid metabolism), as well as many genes without clear evidence of orthology with those of model species. Aggregated across all experimental time point contrasts, we identify 423 genes that are differentially expressed in response to poly(I:C). We also identify 147 genes with altered temporal patterns of expression in response to immune challenge. By characterizing the molecular toolkit involved in hemichordate antiviral immunity, our findings provide vital evolutionary context for understanding the origins of immune systems within Deuterostomia. 

   more » « less
2. Role of Multiple Infections on Immunological Variation in Wild Populations

   https://doi.org/10.1128/mSystems.00099-19  

   Tate, Ann T. (June 2019, mSystems)

   ABSTRACT A central challenge in the fields of evolutionary immunology and disease ecology is to understand the causes and consequences of natural variation in host susceptibility to infectious diseases. As hosts progress from birth to death in the wild, they are exposed to a wide variety of microorganisms that influence their physical condition, immune system maturation, and susceptibility to concurrent and future infection. Thus, multiple exposures to the same or different microbes can be important environmental drivers of host immunological variation and immune priming. In this perspective, I discuss parasite infracommunity interactions and their imprint on host immunity in space and time. I further consider feedbacks from parasite community dynamics within individual hosts on the transmission of disease at higher levels of biological organization and highlight the promise of systems biology approaches, using flour beetles as an example, for studying the role of multiple infections on immunological variation in wild populations. 

   more » « less
3. Leukocyte allometries in birds are not affected by captivity

   https://doi.org/10.1002/jez.2591  

   Martin, Lynn B.; Ruhs, Emily Cornelius; Oakey, Samantha; Downs, Cynthia J. (March 2022, Journal of Experimental Zoology Part A: Ecological and Integrative Physiology)

   Abstract Body size affects many traits, but often in allometric, or disproportionate ways. For example, large avian and mammalian species circulate far more of some immune cells than expected for their size based on simple geometric principles. To date, such hypermetric immune scaling has mostly been described in zoo‐dwelling individuals, so it remains obscure whether immune hyper‐allometries have any natural relevance. Here, we asked whether granulocyte and lymphocyte allometries in wild birds differ from those described in captive species. Our previous allometric studies of avian immune cell concentrations were performed on animals kept for their lifetimes in captivity where conditions are benign and fairly consistent. In natural conditions, infection, stress, nutrition, climate, and myriad other forces could alter immune traits and hence mask any interspecific scaling relationships between immune cells and body size. Counter to this expectation, we found no evidence that immune cell allometries differed between captive and wild species, although we had to rely on cell proportion data, as insufficient concentration data were available for wild species. Our results indicate that even in variable and challenging natural contexts, immune allometries endure and might affect disease ecology and evolution. 

   more » « less
4. Immune System Promiscuity in Human and Nonhuman Primate Evolution

   https://doi.org/10.13110/humanbiology.90.4.01  

   Brinkworth, Jessica F.; Babbitt, Courtney (January 2018, Human biology)

   null (Ed.)

   Many genes that respond to infection have functions outside of immunity and have been found to be under natural selection. Pathogens may therefore incidentally alter nonimmune physiology through engagement with immune system genes. This raises a logical question of how genetically promiscuous the immune system is, here defined as how heavily cross-referenced the immune system is into other physiological systems. This work examined immune gene promiscuity across physiological systems in primates by assessing the baseline (unperturbed) expression of key tissue and cell types for differences, and primate genomes for signatures of selection. These efforts revealed “immune” gene expression to be cross-referenced extensively in other physiological systems in primates. When immune and nonimmune tissues diverge in expression, the differentially expressed genes at baseline are enriched for cell biological activities not immediately identifiable as immune function based. Individual comparisons of immune and nonimmune tissues in primates revealed low divergence in gene expression between tissues, with the exception of whole blood. Immune gene promiscuity increases over evolutionary time, with hominoids exhibiting the most cross-referencing of such genes among primates. An assessment of genetic sequences also found positive selection in the coding regions of differentially expressed genes between tissues functionally associated with immunity. This suggests that, with increasing promiscuity, divergent gene expression between the immune system and other physiological systems tends to be adaptive and enriched for immune functions in hominoids. 

   more » « less
5. Immune System Promiscuity in Human and Nonhuman Primate Evolution

   Brinkworth, J.F.; Babbitt, C.C. (October 2019, Human biology)

   Many genes that respond to infection have functions outside of immunity and have been found to be under natural selection. Pathogens may therefore incidentally alter nonimmune physiology through engagement with immune system genes. This raises a logical question of how genetically promiscuous the immune system is, here defijined as how heavily cross-referenced the immune system is into other physiological systems. This work examined immune gene promiscuity across physiological systems in primates by assessing the baseline (unperturbed) expression of key tissue and cell types for diffferences, and primate genomes for signatures of selection. These effforts revealed “immune” gene expression to be cross-referenced extensively in other physiological systems in primates. When immune and nonim-mune tissues diverge in expression, the diffferentially expressed genes at baseline are enriched for cell biological activities not immediately identifijiable as immune function based. Individual comparisons of immune and nonimmune tissues in primates revealed low divergence in gene expression between tissues, with the exception of whole blood. Immune gene promiscuity increases over evolutionary time, with hominoids exhibiting the most cross-referencing of such genes among primates. An assessment of genetic sequences also found positive selection in the coding regions of diffferentially expressed genes between tissues functionally associated with immunity. This suggests that, with increasing promiscuity, divergent gene expression between the immune system and other physiological systems tends to be adaptive and enriched for immune functions in hominoids. 

   more » « less