Sex-specific variability in the immune system across life-history stages.
ABSTRACT Organisms theoretically manage their immune systems optimally across their life spans to maximize fitness. However, we lack information on (1) how the immune system is managed across life-history stages, (2) whether the sexes manage immunity differentially, and (3) whether immunity is repeatable within an individual. We present a within-individual, repeated-measures experiment examining life-history stage variation in the inflammatory immune response in the zebra finch (Taeniopygia guttata). In juveniles, age-dependent variation in immune response differed in a sex- and context-specific manner, resulting in no repeatability across stages. In adults, females displayed little stage-dependent variation in immune response when laying while receiving a high-quality (HQ) diet; however, laying while receiving a low-quality (LQ) diet significantly reduced both immune responses and reproductive outputs in a manner consistent with a facultative (resource-driven) effect of reproduction on immunity. Moreover, a reduced immune response in females who were raising offspring while receiving an HQ diet suggests a residual effect of the energetic costs of reproduction. Conversely, adult males displayed no variation in immune responses across stages, with high repeatability from the nonbreeding stage to the egg-laying stage, regardless of diet quality (HQ diet, r = 0.51; LQ diet, r = 0.42). Females displayed high repeatability when laying while receiving the HQ diet (r = 0.53); however, repeatability disappeared when individuals received the LQ diet. High-response females receiving the HQ diet had greater immune flexibility than did low-response females who were laying while receiving the LQ diet. Data are consistent with immunity being a highly plastic trait that is sex-specifically modulated in a context-dependent manner and suggest that immunity at one stage may provide limited information about immunity at future stages.
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ABSTRACT: BACKGROUND AND AIMS: Busy clinical settings often restrict the possibility to focus on concepts that determine health in a positive way, commonly assessed by using patient-reported outcomes (PROs). We aimed to explore which determinants of health (DHs) are important to people with Crohn's disease (CD), to understand possible gender differences and to analyze whether these DHs are covered by PROs used in CD. METHODS: Two systematic literature reviews were done to identify relevant DHs and clinically relevant PROs. We conducted a qualitative narrative biographical study and mapped the patients' experiences to concepts that determine health in a positive way. Experiences, DHs and the items of the PROs were compared by the WHO International Classification of Functioning, Disability and Health (ICF) as a common framework. RESULTS: 15 people with CD with a median age of 46years (IQR 34-60) and median disease duration of 15years (IQR 8-30) participated. Self-efficacy, social support, job satisfaction and occupational balance were mentioned most frequently. While participation appeared to have greater meaning to men, appreciation and resilience seemed to be more important for women. Of 18 PROs the Perceived Stress Questionnaire (PSQ), the Inflammatory Bowel disease - Self-efficacy scale (IBD-SES), the Life Orientation Test - Revised (LOT-R) and the Patient Activation Measure 13 (PAM-13) cover most DHs. CONCLUSIONS: This is the first study elaborating the coverage of patient's perspective by commonly used PROs in CD. The findings could support health professionals to focus on DHs in people with CD in clinical practice and research.Journal of Crohn s and Colitis 01/2013; · 3.39 Impact Factor
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ABSTRACT: A general phenomenon in peripartum mammals is the breakdown of (acquired) immunity. The incidence of parasite load, disease and inflammation often rise during the specific energetically demanding time of pregnancy and lactation. In this period, blood leukocytes display decreased DNA synthesis in response to mitogens in vitro. Leukocyte activation, the phase of the cell cycle preceding the DNA synthetic phase has hardly been investigated, but the few studies suggest that leukocyte activation may also be impaired by the limited energy/nutrient availability. Because leukocyte activation is characterized by manifold processes, we used the cellular oxygen consumption rate (OCR) as a measure of ATP turnover to support all these processes. We hypothesized that the activation of peripheral blood mononuclear cells (PBMC) - in terms of oxygen consumed over basal levels after in vitro stimulation - is altered by energy balance around parturition. We studied peripartum high-yielding dairy cows because they undergo substantial fluctuations in energy intake, energy output and body fat mass. We established a fluorescence-based test strategy allowing for long-term (≥24h) quantification of O(2)-consumption and the peripartum period from 5weeks ante partum to 5weeks postpartum. In addition, we determined cellular lactate production, DNA/RNA synthesis and cell size and zoo-technical parameters such as animal energy intake and milk yield were assessed, as well as selected plasma parameters, e.g. glucose concentration. The basal OCR of PBMC from pregnant, non-lactating cows (n=6, -5weeks ante partum) was 1.19±0.15nmolmin(-1) (10(7) cells)(-1) and increased to maximum levels of 2.54±0.49nmolmin(-1) (10(7) cells)(-1) in phytohemagglutinin (PHA)-stimulated PBMC. The basal OCR did not change over the peripartum period. Whereas the activation indices, herein defined as the PHA-induced 24h-increase of OCR above baseline, amounted to 1.1±0.3, 4.2±0.3, 4.1±1.1, 2.1±0.3, and 2.7±0.5 at week -5, -1, +1, +2, and +5 relative to parturition, respectively. Because the activation index was positively correlated to plasma glucose levels and to energy balance during late pregnancy (week -5/week -1) and transition to lactation (week -1/week +2), we conclude that PBMC activation is modulated by energy/nutrient availability. In future studies, the activation index should aid the identification of causal mechanisms of disparity in PBMC activation, such as attenuated ion transport or macromolecule synthesis.Comparative biochemistry and physiology. Part A, Molecular & integrative physiology 10/2012; · 2.20 Impact Factor
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ABSTRACT: Ecoimmunology is an example of how fruitful integrative approaches to biology can be. Since its emergence, ecoimmunology has sparked constructive debate on a wide range of topics, from the molecular mechanics of immune responses to the role of immunity in shaping the evolution of life histories. To complement the symposium Methods and Mechanisms in Ecoimmunology and commemorate the inception of the Division of Ecoimmunology and Disease Ecology within the Society for Integrative and Comparative Biology, we appraise the origins of ecoimmunology, with a focus on its continuing and valuable integration with disease ecology. Arguably, the greatest contribution of ecoimmunology to wider biology has been the establishment of immunity as an integral part of organismal biology, one that may be regulated to maximize fitness in the context of costs, constraints, and complex interactions. We discuss historical impediments and ongoing progress in ecoimmunology, in particular the thorny issue of what ecoimmunologists should, should not, or cannot measure, and what novel contributions ecoimmunologists have made to the understanding of host-parasite interactions. Finally, we highlight some areas to which ecoimmunology is likely to contribute in the near future.Integrative and Comparative Biology 05/2014; · 3.02 Impact Factor