Search results for "Immunity"
showing 10 items of 1537 documents
Models of Immune Aging
2018
Abstract Biochemical changes, impaired immune responses to new antigens, and inflammation-based disorders are commonly found in aged individuals. Thus, many studies have addressed the immune system of healthy elderly, including centenarians, since a well-preserved immune system appears to be a major factor of longevity. Longitudinal studies in humans are complicated, as most immune changes associated with aging develop slowly. Human models of accelerated immune aging in clinical conditions allow exploring the age-related changes in the human immune system and the mechanisms of accelerated aging in chronic infections and autoimmunity. Even if they do not perfectly mimic immune function and i…
Data from: Independent and interactive effects of immune activation and larval diet on adult immune function, growth and development in the greater w…
2018
Organisms in the wild are likely to face multiple immune challenges as well as additional ecological stressors, yet their interactive effects on immune function are poorly understood. Insects are found to respond to cues of increased infection risk by enhancing their immune capacity. However, such adaptive plasticity in immune function may be limited by physiological and environmental constraints. Here, we investigated the effects of two environmental stressors – poor larval diet and an artificial parasite-like immune challenge at the pupal stage – on adult immune function, growth and development in the greater wax moth (Galleria mellonella). Males whose immune system was activated with an …
Data from: Survival after pathogen exposure in group-living insects: don’t forget the stress of social isolation!
2016
A major cost of group-living is its inherent risk of pathogen infection. To limit this risk, many group-living animals have developed the capability to prophylactically boost their immune system in the presence of group members and/or to mount collective defenses against pathogens. These two phenomena, called density dependent prophylaxis and social immunity, respectively, are often used to explain why, in group-living species, individuals survive better in groups than in isolation. However, this survival difference may also reflect an alternative and often overlooked process: a cost of social isolation on individuals’ capability to fight against infections. Here, we disentangled the effect…
Data from: Surrounding pathogens shape maternal egg care but not egg production in the European earwig
2017
Pathogens are ubiquitous in nature and typically entail major fitness costs in their hosts. These costs can be particularly important when individuals exhibit poor immune defenses, as it is often the case during early developmental stages. Hence, selection should favor parental strategies limiting the risks of pathogen exposure and infection in their offspring. In this study, we investigated 1) whether females of the European earwig Forficula auricularia avoid areas contaminated with spores of the entomopathogenic fungus Metarhizium brunneum prior to and at egg laying, as well as 2) whether spore presence entails an increase in females’ investment into both pre-hatching forms of care and cl…
Data from: Host infection history modifies co-infection success of multiple parasite genotypes
2016
1. Co-infections by multiple parasite genotypes are common and have important implications for host-parasite ecology and evolution through within-host interactions. Typically, these infections take place sequentially and therefore, the outcome of co-infection may be shaped by host immune responses triggered by previous infections. For example, in vertebrates specific immune responses play a central role in protection against disease over the course of life, but co-infection research has mostly focused on previously uninfected individuals. 2. Here, we investigated whether sequential exposure and activation of host resistance in rainbow trout Oncorhynchus mykiss affects infection success and …
Data from: Personality, immune response and reproductive success: an appraisal of the pace-of-life syndrome hypothesis
2018
The pace-of-life syndrome (POLS) hypothesis is an extended concept of the life-history theory that includes behavioural traits. The studies challenging the POLS hypothesis often focus on the relationships between a single personality trait and a physiological and/or life-history trait. While pathogens represent a major selective pressure, few studies have been interested in testing relationships between behavioural syndrome, and several fitness components including immunity. The aim of this study was to address this question in the mealworm beetle, Tenebrio molitor, a model species in immunity studies. The personality score was estimated from a multidimensional syndrome based of four repeat…
Data from: Inbreeding-related trade-offs in stress-resistance in the ant Formica exsecta
2014
Inbred individuals and populations are predicted to suffer from inbreeding depression, especially in times of stress. Under natural conditions, organisms are exposed to more than one stressor at any one time, highlighting the importance of stress resistance traits. We studied how inbreeding- and immunity-related traits are correlated under different dietary conditions in the ant Formica exsecta. Its natural diet varies in the amount and nature of plant secondary compounds and the level of free radicals, all of which require detoxification to maintain organismal homeostasis. We found that inbreeding decreased general antibacterial activity under dietary stress, suggesting inbreeding-related …
Data from: Aposematism in the burying beetle? Dual function of anal fluid in parental care and chemical defense
2017
Burying beetles (Nicrophorus vespilloides) bear distinctive and variable orange-black patterning on their elytra and produce an anal exudate from their abdomen when threatened. During breeding, the anal exudates contribute to the antimicrobial defense of the breeding resource. We investigated whether the anal exudates also provide a responsive chemical defense, which is advertised to potential avian predators by the beetle’s orange and black elytral markings. We found that that the orange-black elytral markings of the burying beetle are highly conspicuous for avian predators against range of backgrounds, by using computer simulations. Using bioassays with wood ants, we also showed that the …
The Human Mammary Odour Factor: Variability and Regularities in Sources and Functions
2019
In the course of evolution, human mothers have been, and still are, under strong selective pressure to induce their newborns’ colostrum ingestion promptly after birth. As a concentrate of nutrients, passive immunity, antioxidants, growth factors and symbiotic microbiota, colostrum functions as the evolved antidote to ubiquitous pathogens and threats of neonatal exhaustion. Under such constraints, any means to speed up colostrum/milk intake can only have been beneficial to neonatal viability and adaptive life onset along evolutionary time. The areolar-nipple areas of human lactating females emit lacteal substrates conveying chemostimuli that are attractive and release mouthing and sucking in…
Protection against autoimmunity is driven by thymic epithelial cell–mediated regulation of Tregdevelopment
2021
Medullary thymic epithelial cells (mTECs) are key antigen-presenting cells mediating T cell tolerance to prevent harmful autoimmunity. mTECs both negatively select self-reactive T cells and promote...