The relationship between distress and the development of a primary immune response to a novel antigen

Clinical translation of anti-inflammatory effects of Prevotella histicola in Th1, Th2, and Th17 inflammation

Introduction

EDP1815 is a non-colonizing pharmaceutical preparation of a single stain of Prevotella histicola isolated from the duodenum of a human donor. We report here preclinical and clinical studies showing that the action of EDP1815, an orally delivered and gut restricted single strain of commensal bacteria can regulate inflammatory responses throughout the body.

Methods

Supported by evidence for anti-inflammatory activity in three preclinical mouse models of Th1-, TH2-, and Th17-mediated inflammation, EDP1815 was tested clinically in three Phase 1b studies in patients with psoriasis, patients with atopic dermatitis, and healthy volunteers in a KLH skin challenge model.

Results

Preclinically, EDP1815 was efficacious in all three mouse models of inflammation, showing reduction in skin inflammation as well as related tissue cytokines. In the Phase 1b studies, EDP1815 was found to be well tolerated by participants, with a safety profile comparable to placebo, including no severe or consistent side-effects reported, and no evidence of immunosuppression with no opportunistic infection occurring in these studies. In psoriasis patients, signs of clinical efficacy were seen after 4 weeks of treatment, which continued beyond the treatment period in the higher-dose cohort. In atopic dermatitis patients, improvements were seen throughout the key physician-and patient-reported outcomes. In a healthy-volunteer study of a KLH-induced skin inflammatory response, consistent anti-inflammatory effects were seen in two cohorts through imaging-based measures of skin inflammation.

Discussion

This is the first report demonstrating clinical effects from targeting peripheral inflammation with a non-colonizing gut-restricted single strain of commensal bacteria, providing proof of concept for a new class of medicines. These clinical effects occur without systemic exposure of EDP1815 or modification of the resident gut microbiota, and with placebo-like safety and tolerability. The breadth of these clinical effects of EDP1815, combined with its excellent safety and tolerability profile and oral administration, suggests the potential for a new type of effective, safe, oral, and accessible anti-inflammatory medicine to treat the wide range of diseases driven by inflammation.Clinical Trial Registration: EudraCT # 2018-002807-32; EudraCT # 2018-002807-32; NL8676; https://clinicaltrials.gov/ct2/show/NCT03733353; http://www.trialregister.nl.

In vivo human keyhole limpet hemocyanin challenge in early phase drug development: A systematic review

Experimental exposure of healthy volunteers to the T-cell dependent neoantigen keyhole limpet hemocyanin (KLH) permits the evaluation of immunomodulatory investigational medicinal product (IMP) pharmacology prior to the recruitment of patient populations. Despite widespread use, no standardized approach to the design and conduct of such studies has been agreed. The objective of this systematic review was to survey the published literature where KLH was used as a challenge agent, describing methodology, therapeutic targets addressed, and pharmacodynamic outcome measures. We searched MEDLINE, EMBASE, clinicaltrials.gov, and Cochrane CENTRAL for studies using KLH challenge in humans between January 1, 1994, and April 1, 2022. We described key study features, including KLH formulation, dose, use of adjuvants, route of administration, co-administered IMPs, and end points. Of 2421 titles and abstracts screened, 46 met the inclusion criteria, including 14 (31%) early phase trials of IMP, of which 10 (71%) targeted T-cell co-stimulation. IMPs with diverse mechanisms demonstrated modulation of the humoral response to KLH, suggesting limited specificity of this end point. Two early phase IMP studies (14%) described the response to intradermal re-challenge (delayed type hypersensitivity). Challenge regimens for IMP assessment were often incompletely described, and exhibited marked heterogeneity, including primary KLH dose (25-fold variation: 100-2500 mcg), KLH formulation, and co-administration with adjuvants. Methodological heterogeneity and failure to exploit the access to tissue-level mechanism-relevant end points afforded by KLH challenge has impaired the translational utility of this paradigm to date. Future standardization, characterization, and methodological development is required to permit tailored, appropriately powered, mechanism-dependent study design to optimize drug development decisions.

Impact of oral administration of single strain Lactococcus lactis spp. cremoris on immune responses to keyhole limpet hemocyanin immunization and gut microbiota: A randomized placebo-controlled trial in healthy volunteers

Introduction

Lactococcus lactis spp. cremoris has been associated with promising immunomodulatory results in preclinical trials. The aim of this study was to investigate the pharmacodynamic (PD) effects of three monoclonal microbial formulations of L. lactis spp. cremoris (EDP1066) on the immune response to keyhole limpet hemocyanin (KLH). Potential effects on the gut microbiota were also investigated.

Methods

The trial was registered on Netherlands Trial Register (trial ID NL7519, https://trialsearch.who.int). Eighty-one healthy subjects (median 28, range 18-59 years) were randomized to 28 days of enteric-coated capsules at five doses (n = 13) (1.5 * 1012 total cells daily), freeze-dried powder at one dose (n = 12) (3.0 * 1011 total cells daily) or five doses (n = 12), minitablets at one dose (n = 12) or five doses (n = 12), or placebo (n = 20) prior to KLH immunization. Antibody responses and circulating regulatory T cells (Tregs) were measured after KLH immunization, and skin responses were evaluated after a KLH rechallenge by laser speckle contrast imaging and multispectral imaging. Ex vivo lymphocyte (phytohemagglutinin) and monocyte (lipopolysaccharide (LPS)) cytokine release assays were explored in the minitablet-treated groups only. The prevalence of L. lactis spp. cremoris in the gastrointestinal tract and the impact on the fecal microbiota were assessed by qPCR and 16S rRNA sequencing, respectively.

Results

Repeated-measures analysis of covariances revealed no significant treatment effects on the antibody responses to KLH, number of Tregs, or KLH skin rechallenge outcomes. Ex vivo LPS-driven cytokine responses in whole blood were lower in the low dose minitablet group compared to placebo: tumor necrosis factor (estimated difference (ED) from placebo: -44.2%, 95% confidence interval (CI) -65.3% to -10.3%), interleukin (IL)-1β (ED -41.4%, 95% CI -63.5% to -5.8%), and IL-6 (ED -39.2%, 95% CI -56.8% to -14.5%). The fecal presence of L. lactis spp. cremoris increased during treatment by all EDP1066 formulations and normalized 5 days after the last dose. Microbiome α-diversity did not change by the treatments compared to placebo.

Discussion

The EDP1066 formulations did not affect the immune response to KLH immunization in healthy individuals. However, exposure to L. lactis spp. cremoris in minitablet formulation impacted ex vivo whole blood LPS cytokine response. The clinical impact of these effects awaits further investigations.

Netherlands Trial Register

trialsearch.who.int, trial ID NL7519.

Immune response to vaccination in adults with mental disorders: A systematic review

BACKGROUND

Mental disorders are associated with immune dysregulation as measured by serum levels of biological markers of immunity. Adults with mental disorders have also been reported to have attenuated post vaccine immune response. The COVID-19 pandemic has invited the need to determine whether individuals with mental disorders exhibit differential immune response following the administration of vaccines for other infections.

METHODS

A systematic search of MEDLINE, Embase, Cochrane, and PsycInfo was conducted from inception to May 2021 investigating vaccine response in persons with mental disorders, as measured by biological markers of immunity (i.e., antibodies, cytokines).

RESULTS

Thirteen articles were identified which evaluated vaccine efficacy in persons with mental disorders. Individuals with major depressive disorder (MDD) or schizophrenia revealed attenuated immune response to vaccination, or no statistical difference compared to control subjects. Individuals with anorexia nervosa or post-traumatic stress disorder (PTSD) displayed no attenuated post-vaccination antibody level. Individuals with insomnia displayed lower levels of antibodies after vaccination, whereas individuals with obstructive sleep apnea (OSA) displayed no difference in vaccine response compared to control subjects.

LIMITATIONS

The limitations of this review include the relatively few articles included (n = 13) and small sample sizes (less than thirty subjects) in the majority of articles.

CONCLUSION

Vaccine response in adults with a mental disorder remains inconclusive. Notwithstanding the heterogeneity and relatively small number of studies, available evidence does suggest attenuated immune response across disparate vaccinations. Future research is required to confirm vaccine efficacy in persons with mental disorders, especially regarding immune responses to COVID-19 vaccination.

OX40L Inhibition Suppresses KLH‐driven Immune Responses in Healthy Volunteers: A Randomized Controlled Trial Demonstrating Proof‐of‐Pharmacology for KY1005

The safety, tolerability, immunogenicity, and pharmacokinetic (PK) profile of an anti‐OX40L monoclonal antibody (KY1005, currently amlitelimab) were evaluated. Pharmacodynamic (PD) effects were explored using keyhole limpet hemocyanin (KLH) and tetanus toxoid (TT) immunizations. Sixty‐four healthy male subjects (26.5 ± 6.0 years) were randomized to single doses of 0.006, 0.018, or 0.05 mg/kg, or multiple doses of 0.15, 0.45, 1.35, 4, or 12 mg/kg KY1005, or placebo (6:2). Serum KY1005 concentrations were measured. Antibody responses upon KLH and TT immunizations and skin response upon intradermal KLH administration were performed. PD data were analyzed using repeated measures analysis of covariances (ANCOVAs) and post hoc exposure‐response modeling. No serious adverse events occurred and all adverse events were temporary and of mild or moderate severity. A nonlinear increase in mean serum KY1005 concentrations was observed (median time to maximum concentration (T_max) ~ 4 hours, geometric mean terminal half‐life (t½) ~ 24 days). Cutaneous blood perfusion (estimated difference (ED) −13.4 arbitrary unit (AU), 95% confidence interval (CI) −23.0 AU to −3.8 AU) and erythema quantified as average redness (ED −0.23 AU, 95% CI −0.35 AU to −0.11 AU) decreased after KY1005 treatment at doses of 0.45 mg/kg and above. Exposure‐response analysis displayed a statistically significant treatment effect on anti‐KLH antibody titers (IgG maximum effect (E_max) −0.58 AU, 95% CI −1.10 AU to −0.06 AU) and skin response (erythema E_max −0.20 AU, 95% CI −0.29 AU to −0.11 AU). Administration of KY1005 demonstrated an acceptable safety and tolerability profile and PK analyses displayed a nonlinear profile of KY1005. Despite the observed variability, skin challenge response after KY1005 treatment indicated pharmacological activity of KY1005. Therefore, KY1005 shows potential as a novel pharmacological treatment in immune‐mediated disorders.

A randomized controlled trial with a delayed-type hypersensitivity model using keyhole limpet haemocyanin to evaluate adaptive immune responses in man

AIMS

Keyhole limpet haemocyanin (KLH) immunization is a clinical model for the evaluation of human antibody responses. The current study evaluated the anti-KLH antibody response after KLH immunization and the delayed-type hypersensitivity response following intradermal KLH administration, using objective imaging techniques.

METHODS

Healthy male subjects aged 24.5 ± 5.4 years were randomized to intramuscular immunization with 100 μg KLH (n = 12) or placebo (n = 3). Anti-KLH antibody (Ig) M and IgG titres were determined before and every 7 days after KLH immunization for a total of 28 days. Twenty-one days after the immunization, all subjects received 1 μg KLH intradermally. Prior to and 2 days after intradermal KLH administration, skin blood perfusion, erythema and oedema were quantified using noninvasive imaging tools. Repeated measures ANCOVAs were used to analyse data.

RESULTS

Anti-KLH IgM and IgG titres increased after KLH immunization compared to placebo (estimated difference [ED]: 37%, 95% confidence interval [CI]: 19-51% and ED: 68%, 95% CI: 56-76% respectively). Upon intradermal KLH administration an increase in skin blood perfusion (ED: 10.9 arbitrary units (AU), 95% CI: 1.4-20.4 AU) and erythema (ED: 0.3 AU, 95% CI: 0.1-0.5 AU) was observed in KLH-immunized subjects compared to placebo.

CONCLUSION

KLH immunization followed by intradermal KLH administration resulted in increased anti-KLH IgM and IgG titres and a delayed-type hypersensitivity response quantified by an increase in skin blood perfusion and erythema. Using noninvasive imaging tools the KLH model has the potential to serve as an objective tool to study the pharmacodynamics of T-cell-directed immunomodulatory drugs.

The short-term stress response - Mother nature's mechanism for enhancing protection and performance under conditions of threat, challenge, and opportunity

Our group has proposed that in contrast to chronic stress that can have harmful effects, the short-term (fight-or-flight) stress response (lasting for minutes to hours) is nature's fundamental survival mechanism that enhances protection and performance under conditions involving threat/challenge/opportunity. Short-term stress enhances innate/primary, adaptive/secondary, vaccine-induced, and anti-tumor immune responses, and post-surgical recovery. Mechanisms and mediators include stress hormones, dendritic cell, neutrophil, macrophage, and lymphocyte trafficking/function and local/systemic chemokine and cytokine production. Short-term stress may also enhance mental/cognitive and physical performance through effects on brain, musculo-skeletal, and cardiovascular function, reappraisal of threat/anxiety, and training-induced stress-optimization. Therefore, short-term stress psychology/physiology could be harnessed to enhance immuno-protection, as well as mental and physical performance. This review aims to provide a conceptual framework and targets for further investigation of mechanisms and conditions under which the protective/adaptive aspects of short-term stress/exercise can be optimized/harnessed, and for developing pharmacological/biobehavioral interventions to enhance health/healing, and mental/cognitive/physical performance.

Effects of imidacloprid on Rana catesbeiana immune and nervous system

Imidacloprid (IMD), a neonicotinoid, is generally considered to be of low toxicity in vertebrates. However, the inhibition of acetylcholine (ACh) receptors can have a profound effect on both the immune and nervous system due to the anti-inflammatory effects of ACh. Vertebrates, such as amphibians, might be affected by IMD because they breed in wetlands where the concentration of IMD is high. In our study, we experimentally exposed Rana catesbeiana tadpoles to environmentally relevant IMD and then quantified the ACh and antibody to non-replicating antigens. We hypothesized that IMD exposure would result in higher AChE and antibody levels. We completed a factorial experiment in which tadpoles were divided into four groups, two of which were exposed to 100 ng/L of IMD. After five weeks, two groups were injected with the novel antigen keyhole limpet hemocyanin (KLH) and two injected with a control. Three weeks later, tadpoles were euthanized and blood samples collected. At 100 ng/L, IMD exposure did not cause a significant difference in AChE levels or KLH-specific IgY antibodies. However, tadpoles injected with KLH had slightly higher levels of AChE. In addition, we saw a trend in total IgM with higher levels in tadpoles exposed to IMD. While we found no effect of IMD at 100 ng/L on antibody response to a novel, non-replicating antigen nor on ACh production, further research is needed to determine if higher concentrations of IMD or parasite infection can influence development of R. catesbeiana.

The health and well-being of Australia's future medical doctors: protocol for a 5-year observational cohort study of medical trainees

INTRODUCTION

Clinical training in the undergraduate medical course places multiple stressors on trainees, which have been held to lead to heightened distress, depression, suicide, substance misuse/abuse and poor mental health outcomes. To date, evidence for morbidity in trainees is largely derived from cross-sectional survey-based research. This limits the accuracy of estimates and the extent to which predispositional vulnerabilities (biological and/or psychological), contextual triggers and longer-term consequences can be validly identified. Longitudinal clinical assessments embedded within a biopsychosocial framework are needed before effective preventative and treatment strategies can be put in place.

METHODS AND ANALYSIS

This study is an observational longitudinal cohort study of 330 students enrolled in the undergraduate medicine course at the University of New South Wales (UNSW) Sydney, Australia. Students will be recruited in their fourth year of study and undergo annual assessments for 4 consecutive years as they progress through increasingly demanding clinical training, including internship. Assessments will include clinical interviews for psychiatric morbidity, and self-report questionnaires to obtain health, psychosocial, performance and functioning information. Objective measures of cognitive performance, sleep/activity patterns as well as autonomic and immune function (via peripheral blood samples) will be obtained. These data will be used to determine the prevalence, incidence and severity of mental disorder, elucidate contextual and biological triggers and mechanisms underpinning psychopathology and examine the impact of psychopathology on performance and professional functioning.

ETHICS AND DISSEMINATION

Ethics approval has been granted by the UNSW human research ethics committee (reference HC16340). The findings will be disseminated through peer-reviewed publications and conference presentations, and distributed to key stakeholders within the medical education sector. The outcomes will also inform targeted preventative and treatment strategies to enhance stress resilience in trainee doctors.

Stress, Inflammation and Pain: A Potential Role for Monocytes in Fibromyalgia-related Symptom Severity

The possibility that immunological changes might contribute to symptom severity in fibromyalgia (FM) prompted this proof-of-concept study to determine whether differences in monocyte subpopulations might be present in persons with FM compared with healthy controls. Relationships were assessed by comparing specific symptoms in those with FM (n = 20) and patterns of monocyte subpopulations with healthy age-matched and gender-matched controls (n = 20). Within the same time frame, all participants provided a blood sample and completed measures related to pain, fatigue, sleep disturbances, perceived stress, positive and negative affect and depressed mood (and the Fibromyalgia Impact Questionnaire for those with FM). Monocyte subpopulations were assessed using flow cytometry. No differences were observed in total percentages of circulating monocytes between the groups; however, pain was inversely correlated with percentages of circulating classical (r = -0.568, p = 0.011) and intermediate (r = -0.511, p = 0.025) monocytes in the FM group. Stress and pain were highly correlated (r = 0.608, p = 0.004) in the FM group. The emerging pattern of changes in the percentages of circulating monocyte subpopulations concomitant with higher ratings of perceived pain and the correlation between stress and pain found in the FM group warrant further investigation. Copyright © 2015 John Wiley & Sons, Ltd.

Psychoneuroimmunology: Then and Now

Psychoneuroimmunology (PNI) emerged in the neurosciences in the late 1970s to early 1980s and has extended to influence the fields of psychology, psychiatry, endocrinology, physiology, and the biomedical research community. This review documents the journey of PNI from the early 1980s to the present. Today, we recognize that the highly complex immune system interacts with an equally complex nervous system in a bidirectional manner. Evolutionarily old signals continue to play a role in these communications, as do mechanisms for protection of the host. The disparity between physical and psychological stressors is only an illusion. Host defense mechanisms respond in adaptive and meaningful ways to both. The present review will describe a new way of thinking about evolutionarily old molecules, heat shock proteins, adding to a body of evidence suggesting that activation of the acute stress response is a double-edged sword that can both benefit and derail optimal immunity.

Acute and chronic psychological stress as risk factors for cardiovascular disease: Insights gained from epidemiological, clinical and experimental studies

Cardiovascular disease (CVD) remains a leading cause of death worldwide and identification and therapeutic modulation of all its risk factors is necessary to ensure a lower burden on the patient and on society. The physiological response to acute and chronic stress exposure has long been recognized as a potent modulator of immune, endocrine and metabolic pathways, however its direct implications for cardiovascular disease development, progression and as a therapeutic target are not completely understood. More and more attention is given to the bidirectional interaction between psychological and physical health in relation to cardiovascular disease. With atherosclerosis being a chronic disease starting already at an early age the contribution of adverse early life events in affecting adult health risk behavior, health status and disease development is receiving increased attention. In addition, experimental research into the biological pathways involved in stress-induced cardiovascular complications show important roles for metabolic and immunologic maladaptation, resulting in increased disease development and progression. Here we provide a concise overview of human and experimental animal data linking chronic and acute stress to CVD risk and increased progression of the underlying disease atherosclerosis.

Keyhole limpet haemocyanin - a model antigen for human immunotoxicological studies

Immunization with a T-cell dependent antigen has been promoted as a reliable and sensitive tool for assessing the influence of putative immunotoxic exposures or agents on immune function. Keyhole limpet haemocyanin (KLH) is a very large, copper-containing protein molecule derived from the haemolymph of the inedible mollusc, Megathura crenulata. KLH is a highly immunogenic T-cell dependent antigen that is used increasingly in immunotoxicological studies, particularly in those involving animals. This report systematically reviews the human clinical studies that have used trans-cutaneous KLH immunization for assessment of the influence of various physiological and disease states and exposures on immune function over the last 20 years (1994-2013). These studies varied in their immunization protocols, formulation of KLH, dose, site and route of administration and immunoassay platforms developed to assess KLH-specific responses. KLH immunization has been well tolerated with only mild to moderate adverse effects reported. Though very promising as a model antigen candidate in immunotoxicology research, more work on standardizing immunization and immunoassay protocols is required.

Social status, immune response and parasitism in males: a meta-analysis

In male vertebrates, two conflicting paradigms--the energetic costs of high dominance rank and the chronic stress of low rank--have been proposed to explain patterns of immune function and parasitism. To date, neither paradigm has provided a complete explanation for status-related differences in male health. Here, we applied meta-analyses to test for correlations between male social status, immune responses and parasitism. We used an ecoimmunological framework, which proposes that males should re-allocate investment in different immune components depending on the costs of dominance or subordination. Spanning 297 analyses, from 77 studies on several vertebrate taxa, we found that most immune responses were similar between subordinate and dominant males, and neither dominant nor subordinate males consistently invested in predictable immune components. However, subordinate males displayed significantly lower delayed-type hypersensitivity and higher levels of some inflammatory cytokines than dominant males, while dominant males exhibited relatively lower immunoglobulin responses than subordinate males. Despite few differences in immunity, dominant males exhibited consistently higher parasitism than subordinate males, including protozoan blood parasites, ectoparasites and gastrointestinal helminths. We discuss our results in the context of the costs of dominance and subordination and advocate future work that measures both parasitism and immune responses in wild systems.

High altitude impairs in vivo immunity in humans

The aim was to assess the effect of high altitude on the development of new immune memory (induction) using a contact sensitization model of in vivo immunity. We hypothesized that high-altitude exposure would impair induction of the in vivo immune response to a novel antigen, diphenylcyclopropenone (DPCP). DPCP was applied (sensitization) to the lower back of 27 rested controls at sea level and to ten rested mountaineers 28 hours after passive ascent to 3777 m. After sensitization, mountaineers avoided strenuous exercise for a further 24 hours, after which they completed alpine activities for 11-18 days. Exactly 4 weeks after sensitization, the strength of immune memory induction was quantified in rested mountaineers and controls at sea level, by measuring the response to a low, dose-series DPCP challenge, read at 48 hours as skin measures of edema (skinfold thickness) and redness (erythema). Compared with control responses, skinfold thickness and erythema were reduced in the mountaineers (skinfold thickness,-52%, p=0.01, d=0.86; erythema, -36%, p=0.02, d=0.77). These changes in skinfold thickness and erythema were related to arterial oxygen saturation (r=0.7, p=0.04), but not cortisol (r<0.1, p>0.79), at sensitization. In conclusion, this is the first study to show, using a contact sensitization model of in vivo immunity, that high altitude exposure impairs the development of new immunity in humans.

Development of the scale of psychosocial factors in food allergy (SPS-FA)

BACKGROUND

Food allergy (FA) is a growing condition among children and it's psychological impact over the patients and their caregivers is well known, establishing a vicious circle that perpetuates stress levels. However, psychosocial factors are not commonly included in allergy treatments. Based on the lack of evidence of records about a scale that indicates the level of interaction between biopsychosocial factors in the patient-caregivers dyad for FA, the present research aims to develop a scale with these characteristics as a helpful tool to achieve a more comprehensive system of health care.

METHODS

A preliminary 28-item scale was generated (sample N = 99). The scale was adjusted in contents and language after expert opinion and application on patients. A factor analysis was carried out selecting the items from the final scale.

RESULTS

The final 9-item scale included three areas: impact on quality of life, social impact and conflicts. The scale had a good internal consistency (Cronbach's α = 0.870) and correlated significantly with anxiety and depression measurements. Moreover, it was able to discriminate between study groups (members and non-members of peer support groups) and proved construct validity.

CONCLUSIONS

The SPS-FA is the first scale for the assessment of the interaction of biopsychosocial factors on FA that includes the patient-caregiver dyad. Its application might be relevant for future research, and it can provide the clinician and the researcher with a solid tool to define which type of psychosocial support is required to provide a more comprehensive care in FA.

Mindfulness-based stress reduction for older adults: effects on executive function, frontal alpha asymmetry and immune function

BACKGROUND/AIMS

Mindfulness-based stress reduction (MBSR) has enhanced cognition, positive emotion, and immunity in younger and middle-aged samples; its benefits are less well known for older persons. Here we report on a randomized controlled trial of MBSR for older adults and its effects on executive function, left frontal asymmetry of the EEG alpha band, and antibody response.

METHODS

Older adults (n = 201) were randomized to MBSR or waiting list control. The outcome measures were: the Trail Making Test part B/A (Trails B/A) ratio, a measure of executive function; changes in left frontal alpha asymmetry, an indicator of positive emotions or approach motivation; depression, mindfulness, and perceived stress scores, and the immunoglobulin G response to a protein antigen, a measure of adaptive immunity.

RESULTS

MBSR participants had a lower Trails B/A ratio immediately after intervention (p < 0.05); reduced shift to rightward frontal alpha activation after intervention (p = 0.03); higher baseline antibody levels after intervention (p < 0.01), but lower antibody responses 24 weeks after antigen challenge (p < 0.04), and improved mindfulness after intervention (p = 0.023) and at 21 weeks of follow-up (p = 0.006).

CONCLUSIONS

MBSR produced small but significant changes in executive function, mindfulness, and sustained left frontal alpha asymmetry. The antibody findings at follow-up were unexpected. Further study of the effects of MBSR on immune function should assess changes in antibody responses in comparison to T-cell-mediated effector functions, which decline as a function of age.

Psychological stress and immunoprotection versus immunopathology in the skin

Stress is thought to suppress immune function and increase susceptibility to infections and cancer. Paradoxically, stress is also known to exacerbate autoimmune/proinflammatory disorders (eg, psoriasis, atopic dermatitis) that should be ameliorated by immunosuppression. Here we review studies showing that although chronic stress (lasting for weeks/months/years) can suppress/dysregulate immune function, acute stress (lasting for minutes to hours) can have immunoenhancing effects. Short-term stress experienced at the time of immune activation enhances dendritic cell, neutrophil, macrophage, and lymphocyte trafficking, maturation, and function, and has been shown to augment innate and adaptive immunity; therefore, depending on the conditions of immune activation, and the nature of the activating antigen, short-term stress can enhance the acquisition and expression of immunoprotection or immunopathology. In contrast, chronic stress suppresses or dysregulates innate and adaptive immune responses by altering the Type 1-Type 2 cytokine balance, inducing low-grade chronic increases in proinflammatory factors, and suppressing numbers, trafficking, and function of immunoprotective cells. Chronic stress also increases susceptibility to skin cancer by suppressing Type 1 cytokines and protective T cells while increasing regulatory/suppressor T cell number/function. It is important to recognize that the adaptive function of a physiological stress response is to promote survival. Stress-related neurotransmitters, hormones, and factors act as biological alarm signals that prepare the immune and other physiological systems for potential challenges (eg, wounding or infection) perceived by the brain (eg, detection of an attacker); however, this may exacerbate immunopathology (eg, psoriasis, atopic dermatitis) if the enhanced immune response is directed against innocuous or self-antigens, or if the system is chronically activated as seen during long-term stress. In view of the ubiquitous nature of stress and its significant effects on immunoprotection and immunopathology, it is important to further elucidate the mechanisms mediating both the salubrious and the harmful effects of stress, and to meaningfully translate findings from bench to bedside.

Toward identifying the effects of the specific components of Mindfulness-Based Stress Reduction on biologic and emotional outcomes among older adults

OBJECTIVES

The objectives of this study were to examine the effects of specific Mindfulness-Based Stress Reduction (MBSR) activities (yoga, sitting and informal meditation, body scan) on immune function, circulating insulin-like growth factor (IGF)-1 concentrations, and positive affect among older adults.

DESIGN

The study design comprised longitudinal analyses of data from subjects in an 8-week MBSR program.

SETTING

The study was conducted at a University-affiliated health center.

SUBJECTS

This study involved 100 community-dwelling older adults. Inclusion criteria were as follows: ≥65 years of age and English-speaking.

INTERVENTION

This was an 8-week MBSR program.

OUTCOME MEASURES

Interleukin (IL)-6 and IGF-1 levels were assayed from blood collected at postintervention assessments. Participants were immunized postintervention with keyhole limpet hemocyanin (KLH), and immunoglobulin (Ig)M and IgG KLH-specific antibody responses were measured prior to immunization as well as 3 weeks and 24 weeks postintervention. Participants completed a 10-item measure of positive affect at study entry and postintervention.

RESULTS

Participants maintained weekly practice logs documenting participation in yoga, sitting meditation, informal meditation, and body scan. More practice of yoga was associated with higher post-treatment IGF-1 levels and greater improvement in positive affect from study entry to postintervention. Sitting meditation was positively associated with post-treatment IGF-1. Greater use of body scanning was associated with reduced antigen-specific IgM and IgG 3 weeks postintervention but not 24 weeks. No associations were found between MBSR activities and IL-6 levels.

CONCLUSIONS

Practice of MBSR activities, particularly yoga, could provide benefits for specific aspects of physiologic function and positive affect. Changes in adaptive immunity in older adult MBSR practitioners warrant further study.

Exercise-induced stress inhibits both the induction and elicitation phases of in vivo T-cell-mediated immune responses in humans

Little is known about the influence of exercise on induction and elicitation phases of in vivo immunity in humans. We used experimental contact-hypersensitivity, a clinically relevant in vivo measure of T cell-mediated immunity, to investigate the effects of exercise on induction and elicitation phases of immune responses to a novel antigen. The effects of 2 h-moderate-intensity-exercise upon the induction (Study One) and elicitation of in vivo immune memory (Study Two) to diphenylcyclopropenone (DPCP) were examined. Study One: matched, healthy males were randomly-assigned to exercise (N=16) or control (N=16) and received a primary DPCP exposure (sensitization), 20 min after either 2 h running at 60% V O(2peak) (EX) or 2 h seated rest (CON). Four weeks later, participants received a low, dose-series DPCP challenge (elicitation) on their upper inner arm, which was read at 24 and 48 h as clinical score, oedema (skinfold thickness) and redness (erythema). Study Two: pilot; 13 healthy males were sensitized to DPCP. Elicitation challenges were repeated every 4 weeks until responses reached a reproducible plateau. Then, N=9 from the pilot study completed both EX and CON trials in a randomized order. Elicitation challenges were applied and evaluated as in Study One. Results demonstrate that exercise-induced stress significantly impairs both the induction (oedema -53% at 48 h; P<0.001) and elicitation (oedema -19% at 48 h; P<0.05) phases of the in vivo T-cell-mediated immune response. These findings demonstrate that prolonged moderate-intensity exercise impairs the induction and elicitation phases of in vivo T-cell-mediated immunity. Moreover, the induction component of new immune responses appears more sensitive to systemic-stress-induced modulation than the elicitation component.

Antibody response to vaccination as a marker of in vivo immune function in psychophysiological research

The hunt for novel tools to investigate empirical questions is ever present in psychophysiological research. Antibody response to vaccination has received increasing attention over recent years as a useful measure of in vivo immune function. There is now considerable evidence that the magnitude of the antibody response to vaccination is associated with a wide range of psychosocial factors. Further, there are preliminary indications that manipulating psychosocial variables, using both chronic and acute interventions, can also alter the efficacy of the vaccination. This review will discuss the theoretical and clinical relevance of the vaccine model in this context, and will address key methodological considerations for researchers considering adopting this approach. The review will also address how the strategic use of this model could help researchers further elucidate some of the remaining theoretical issues.

Psychological factors, immune function and recovery from major surgery

OBJECTIVE

This study used a prospective design and the technique of structural modelling to examine the complex interrelations between psychological factors, immune status and complications after major surgery.

METHODS

Twenty-nine women scheduled for elective cholecystectomy were studied prospectively. Information regarding medical history, health practices, life stressors, and coping strategies was obtained two weeks prior to admission. At this initial meeting, as well as three days after surgery, and at one month follow-up immunological tests were performed and the level of psychological distress was assessed. The study additionally included measures of post-operative complications, and infections and negative effect during follow-up.

RESULTS

Pre-operative immune status emerged as a key variable exerting strong effects on subsequent immune function and, thereby producing significant, indirect effects on every recovery variable. Pre-operative distress was directly linked to increased mood disturbance at follow-up. Moreover, distress significantly influenced immune function both before and after surgery, which mediated a significant impact on most recovery variables. Active coping behaviour directly increased the risk of a complicated recovery.

CONCLUSIONS

The study demonstrated that distress-induced changes in immune functioning have clinical relevance. Overall, the present findings suggest that recovery from surgery is facilitated in patients with a well-functioning immune system, a low-level of pre-operative distress and a passive coping disposition.

A hassle a day may keep the pathogens away: The fight-or-flight stress response and the augmentation of immune function

Stress is known to suppress or dysregulate immune function and increase susceptibility to disease. Paradoxically, the short-term fight-or-flight stress response is one of nature's fundamental defense mechanisms that galvanizes the neuroendocrine, cardiovascular, and musculoskeletal systems into action to enable survival. Therefore, it is unlikely that short-term stress would suppress immune function at a time when it may be critically required for survival (e.g., in response to wounding and infection by a predator or aggressor). In fact, studies have shown that stress can enhance immune function under certain conditions. Several factors influence the direction (enhancing versus suppressive) of the effects of stress on immune function: (1) DURATION: acute or short-term stress experienced at the time of activation of an immune response enhances innate and adaptive immune responses. Chronic or long-term stress can suppress or dysregulate immune function. (2) Leukocyte distribution: compartments (e.g., skin), that are enriched with immune cells during acute stress show immuno-enhancement, while those that are depleted of leukocytes (e.g., blood), show immuno-suppression. (3) The differential effects of physiologic versus pharmacologic stress hormones: Endogenous hormones in physiological concentrations can have immuno-enhancing effects. Endogenous hormones at pharmacologic concentrations, and synthetic hormones, are immuno-suppressive. (4) Timing: immuno-enhancement is observed when acute stress is experienced during the early stages of an immune response while immuno-suppression may be observed at late stages. The type of immune response (protective, regulatory/inhibitory, or pathological) that is affected determines whether the effects of stress are ultimately beneficial or harmful for the organism. Arguments based on conservation of energy have been invoked to explain potential adaptive benefits of stress-induced immuno-suppression, but generally do not hold true because most mechanisms for immuno-suppression expend, rather than conserve, energy. We propose that it is important to study, and if possible, to clinically harness, the immuno-enhancing effects of the acute stress response that evolution has finely sculpted as a survival mechanism, just as we study its maladaptive ramifications (chronic stress) that evolution has yet to resolve.

Enhancing versus suppressive effects of stress on immune function: implications for immunoprotection and immunopathology

Stress is known to suppress immune function and increase susceptibility to infections and cancer. Paradoxically, stress is also known to exacerbate asthma, and allergic, autoimmune and inflammatory diseases, although such diseases should be ameliorated by immunosuppression. Moreover, the short-term fight-or-flight stress response is one of nature's fundamental defense mechanisms that enables the cardiovascular and musculoskeletal systems to promote survival, and it is unlikely that this response would suppress immune function at a time when it is most required for survival (e.g. in response to wounding and infection by a predator or aggressor). These observations suggest that stress may suppress immune function under some conditions while enhancing it under others. The effects of stress are likely to be beneficial or harmful depending on the type (immunoprotective, immunoregulatory/inhibitory, or immunopathological) of immune response that is affected. Studies have shown that several critical factors influence the direction (enhancing vs. suppressive) of the effects of stress or stress hormones on immune function: (1) Duration (acute vs. chronic) of stress: Acute or short-term stress experienced at the time of immune activation can enhance innate and adaptive immune responses. Chronic or long-term stress can suppress immunity by decreasing immune cell numbers and function and/or increasing active immunosuppressive mechanisms (e.g. regulatory T cells). Chronic stress can also dysregulate immune function by promoting proinflammatory and type-2 cytokine-driven responses. (2) Effects of stress on leukocyte distribution: Compartments that are enriched with immune cells during acute stress show immunoenhancement, while those that are depleted of leukocytes, show immunosuppression. (3) The differential effects of physiologic versus pharmacologic concentrations of glucocorticoids, and the differential effects of endogenous versus synthetic glucocorticoids: Endogenous hormones in physiological concentrations can have immunoenhancing effects. Endogenous hormones at pharmacologic concentrations, and synthetic hormones, are immunosuppressive. (4) The timing of stressor or stress hormone exposure relative to the time of activation and time course of the immune response: Immunoenhancement is observed when acute stress is experienced at early stages of immune activation, while immunosuppression may be observed at late stages of the immune response. We propose that it is important to study and, if possible, to clinically harness the immunoenhancing effects of the acute stress response, that evolution has finely sculpted as a survival mechanism, just as we study its maladaptive ramifications (chronic stress) that evolution has yet to resolve. In view of the ubiquitous nature of stress and its significant effects on immunoprotection as well as immunopathology, it is important to further elucidate the mechanisms mediating stress-immune interactions and to meaningfully translate findings from bench to bedside.

Cardiovascular exercise intervention improves the primary antibody response to keyhole limpet hemocyanin (KLH) in previously sedentary older adults

Based upon a prior cross-sectional study, we hypothesized that an aerobic exercise intervention in sedentary older adults would improve a primary T cell-dependent immune response. Participants were a subset of older subjects from a large, ongoing exercise intervention study who were randomly assigned to either an aerobic exercise (Cardio, n=30, 68.9+0.8 years) or flexibility/balance (Flex, n=20, 69.9+1.2 years) intervention. The intervention consisted of either three aerobic sessions for 30-60 min at 55-70% VO(2 max) or two 60 min flexibility/balance sessions weekly for 10 months. Eight months into the intervention, samples were collected before intramuscular administration of KLH (125 microg), followed by sampling at 2, 3, and 6 weeks post-KLH. Serum anti-KLH IgM, IgG1, and IgG2 was measured by ELISA. Physiological and psychosocial measures were also assessed pre- and post-intervention. While there was no difference in the anti-KLH IgG2 response between groups, Cardio displayed significantly (p<0.05) higher anti-KLH IgG1 (at weeks 2, 3, and 6 post) and IgM responses when compared to Flex. Despite cardiovascular intervention-induced improvement in physical fitness (approximately 11% vs. 1% change in VO(2 peak) in Cardio vs. Flex, respectively), we found no relationship between improved fitness and enhanced anti-KLH antibody responses. Optimism, perceived stress, and affect were all associated with enhanced immune response. We have shown for the first time that cardiovascular training in previously sedentary elderly results in significantly higher primary IgG1 and IgM antibody responses, while having no effect on IgG2 production.

Enhancing versus Suppressive Effects of Stress on Immune Function: Implications for Immunoprotection versus Immunopathology

It is widely believed that stress suppresses immune function and increases susceptibility to infections and cancer. Paradoxically, stress is also known to exacerbate allergic, autoimmune, and inflammatory diseases. These observations suggest that stress may have bidirectional effects on immune function, being immunosuppressive in some instances and immunoenhancing in others. It has recently been shown that in contrast to chronic stress that suppresses or dysregulates immune function, acute stress can be immunoenhancing. Acute stress enhances dendritic cell, neutrophil, macrophage, and lymphocyte trafficking, maturation, and function and has been shown to augment innate and adaptive immune responses. Acute stress experienced prior to novel antigen exposure enhances innate immunity and memory T-cell formation and results in a significant and long-lasting immunoenhancement. Acute stress experienced during antigen reexposure enhances secondary/adaptive immune responses. Therefore, depending on the conditions of immune activation and the immunizing antigen, acute stress may enhance the acquisition and expression of immunoprotection or immunopathology. In contrast, chronic stress dysregulates innate and adaptive immune responses by changing the type 1-type 2 cytokine balance and suppresses immunity by decreasing leukocyte numbers, trafficking, and function. Chronic stress also increases susceptibility to skin cancer by suppressing type 1 cytokines and protective T cells while increasing suppressor T-cell function. We have suggested that the adaptive purpose of a physiologic stress response may be to promote survival, with stress hormones and neurotransmitters serving as beacons that prepare the immune system for potential challenges (eg, wounding or infection) perceived by the brain (eg, detection of an attacker). However, this system may exacerbate immunopathology if the enhanced immune response is directed against innocuous or self-antigens or dysregulated following prolonged activation, as seen during chronic stress. In view of the ubiquitous nature of stress and its significant effects on immunoprotection and immunopathology, it is important to further elucidate the mechanisms mediating stress-immune interactions and to meaningfully translate findings from bench to bedside.

The Acute Stress-Induced Immunoenhancement Hypothesis

Acute stress, such as a bout of exercise, is accepted to cause an array of immunologic changes. Recently, it has been proposed that acute stress activation of the innate immune system might be harnessed as an adjuvant to enhance immune responses to antigen challenge. This review develops the acute stress-induced immunoenhancement hypothesis and its possible role as a vaccine adjuvant.

Does genotype mask the relationship between psychological factors and immune function?

This paper examined the interaction between genetic influences of the polymorphic human leukocyte antigens (DRB1 and DQB1) and psychological distress on the development of cellular immunity to the novel antigen, keyhole limpet hemocyanin (KLH). Participants (n = 227) were immunized with KLH and the development of cutaneous delayed-type hypersensitivity (DTH) against KLH was examined 3 weeks later. Distress was assessed using the Profile of Mood States. DNA was typed for the serologically defined DRB1 and DQB1 antigens. There was a significant correlation between distress at immunization and the development of DTH skin test responses to KLH (n = 214, r = .24, p = .003). HLA DQ2 was weakly associated with a decreased likelihood of developing a cutaneous delayed-type hypersensitivity response against KLH (odds ratio [OR] = 1.6; confidence interval [CI] 0.9-2.7). HLA DQ5 was weakly associated with an increased likelihood of responding to the antigen (OR=0.6; CI=0.3-1.0). The correlation between distress and immune function in HLA DQ2 negative individuals was .34 (n = 136, p = .00) and in HLA DQ2 positive individuals it was .06 (n = 74, p =. 64). For HLA DQ5 negative individuals the correlation was .26 (n = 140, p = .00) and for HLA DQ5 positive individuals it was .22 (n = 70, p = .07). These results suggest that the distress/immune relationship in genetically susceptible or protected individuals may be underestimated in psychoneuroimmunology research.

Influence of age and physical activity on the primary in vivo antibody and T cell-mediated responses in men

The aging immune system is characterized by the progressive decline in the antibody and T cell-mediated responses to antigen. Little is known, however, about the benefits of exercise in aging on the generation of a primary immune response to antigen and the subsequent antibody and memory T cell-mediated response. Most in vivo immune research to date has utilized vaccines or recall antigens to elicit an immune response. Therefore, the purpose of this experiment was to examine the association of aging and physical activity on the primary antibody and T cell response to the novel protein antigen keyhole-limpet hemocyanin (KLH). Forty-six physically active and sedentary, young (20-35 yr) and older (60-79 yr) men were recruited. Subjects were intramuscularly immunized with 100 microg of KLH, and blood samples were collected at days 0, 7, 14, 21, and 28. Samples were measured for anti-KLH IgM, IgG, IgG1, and IgG2 by ELISA. On day 21 after intramuscular KLH administration, subjects received an intradermal injection with 1 microg of KLH of inflammation recorded at 24, 48, 72, 96, and 120 h to assess anti-KLH delayed-type hypersensitivity response. There was a significant reduction in all anti-KLH measures with aging except for anti-KLH IgG2. The physically active older group had significantly higher anti-KLH IgM, IgG, IgG1, and delayed-type hypersensitivity responses, but not IgG2 compared with the sedentary older group. In conclusion, regular physical activity in older men is associated with a more robust immune response to novel antigenic challenge.

Shingles Immunity and Health Functioning in the Elderly: Tai Chi Chih as a Behavioral Treatment

Both the incidence and severity of herpes zoster (HZ) or shingles increase markedly with increasing age in association with a decline in varicella zoster virus (VZV)-specific immunity. Considerable evidence shows that behavioral stressors, prevalent in older adults, correlate with impairments of cellular immunity. Moreover, the presence of depressive symptoms in older adults is associated with declines in VZV-responder cell frequency (VZV-RCF), an immunological marker of shingles risk. In this review, we discuss recent findings that administration of a relaxation response-based intervention, tai chi chih (TCC), results in improvements in health functioning and immunity to VZV in older adults as compared with a control group. TCC is a slow moving meditation consisting of 20 separate standardized movements which can be readily used in elderly and medically compromised individuals. TCC offers standardized training and practice schedules, lending an important advantage over prior relaxation response-based therapies. Focus on older adults at increased risk for HZ and assay of VZV-specific immunity have implications for understanding the impact of behavioral factors and a behavioral intervention on a clinically relevant end-point and on the response of the immune system to infectious pathogens.

Influences of distress and alcohol consumption on the development of a delayed-type hypersensitivity skin test response

OBJECTIVE

This paper reports the effects of naturally occurring levels of distress on the development of delayed-type hypersensitivity (DTH) skin test responses. These in vivo measures provide a biologically relevant assessment of cellular immune competence.

METHODS

Subjects (N = 166) were immunized (baseline) with the novel antigen, keyhole limpet hemocyanin (KLH), and DTH skin test responses against KLH were assessed 3 weeks later (follow-up). The CMI Multitest (Merieux, France), which evaluates DTH responses to a panel of seven antigens, was also administered at follow-up. Emotional distress was assessed at baseline and follow-up by the Profile of Mood States.

RESULTS

Distress levels at baseline were associated with a reduced likelihood of developing DTH responses against KLH at follow-up (r = -0.22, p =.01). There was no relationship between distress at follow-up and cutaneous DTH in response to KLH (r = 0.09, p =.24) or in the Multitest (r = -0.03, p =.70). In addition, higher levels of alcohol consumption at baseline (r = -0.19, p =.02) and at follow-up (r = -0.20, p =.01) were associated with a decreased likelihood of developing cutaneous DTH against KLH.

CONCLUSIONS

Everyday levels of distress predicted the capacity of the cellular arm of the immune system to exhibit recall responses to an antigen, when the experimental paradigm allowed the assessment of distress at the time of antigen sensitization. Moderate alcohol consumption independently affected cutaneous DTH.