The time course of the inflammatory response to the Salmonella typhi vaccination

Inflamed but not impulsive: Acute inflammatory cytokine response does not impact prepotent response inhibition

BACKGROUND

Prior evidence has linked inflammation with impulsivity, but most of this evidence is cross-sectional. In this study, we provoked an acute inflammatory cytokine response to see whether it lowered prepotent response inhibition on three cognitive tasks.

METHOD

This study features secondary analyses from a randomized crossover trial in which 171 postmenopausal breast cancer survivors (Stage I-IIIA) each received a typhoid capsular polysaccharide vaccination and a saline placebo injection in a random sequence at two separate visits at least one month apart. Participants completed the Stroop Color-Discrepant Task, the 2-back, and the Conners Continuous Performance Test (CPT) on the computer between 5 and 7 h after the injections. They had their blood drawn once before and repeatedly after the injection to measure interleukin-1 receptor antagonist and interleukin-6 responses.

RESULTS

Women committed marginally fewer errors on the Stroop color-discrepant trials after the typhoid vaccine (M = 0.36, SE = 0.08), compared to placebo (M = 0.54, SE = 0.09, p = .076). Injection type did not predict 2-back accuracy (p = .80) or CPT commission errors (p = .47). Inflammatory cytokine responses were also unrelated to the outcomes of interest (ps>.16).

CONCLUSION

We found no evidence that an acute inflammatory cytokine response provokes response disinhibition - an important facet of impulsivity. In fact, our only marginally non-significant result suggested that women were better able to inhibit their prepotent responses on the Stroop after receiving the typhoid vaccine, compared to placebo. Further experimental tests of the acute inflammatory cytokine response's effect on other aspects of impulsivity are warranted.

LIMITATIONS

The sample was female, primarily White, highly educated cancer survivors, and recruitment was not premised on impulsive traits or diagnosis with an impulsive-related disorder. Also, there are many facets of impulsivity, and this study only measured response inhibition.

Can Inflammation Predict Social Media Use? Linking a Biological Marker of Systemic Inflammation with Social Media Use Among College Students and Middle-Aged Adults

Drawing on recent evidence that inflammation may promote social affiliative motivation, the present research proposes a novel perspective that inflammation may be associated with more social media use. In a cross-sectional analysis of a nationally representative sample, Study 1 (N = 863) found a positive association between C-reactive protein (CRP), a biomarker of systemic inflammation, and the amount of social media use by middle-aged adults. Study 2 (N = 228) showed that among college students CRP was prospectively associated with more social media use 6 weeks later. Providing stronger evidence of the directionality of this effect, Study 3 (N = 171) showed that in college students CRP predicted increased social media use in the subsequent week even after controlling for current week's use. Additionally, in exploratory analyses of CRP and different types of social media use in the same week, CRP was only associated with using social media for social interaction and not for other purposes (e.g., entertainment). The present research sheds light on the social effects of inflammation and highlights potential benefits of using social media as a context for studying the impact of inflammation on social motivation and behavior.

Effects of an experimentally induced inflammatory stimulus on motivational behavior in remitted depressed patients

BACKGROUND

Acute inflammation is associated with sickness behavior characterized by reduced motivation for pleasurable activities in humans. The current study investigated the effect of an experimentally induced inflammatory stimulus on motivational reward in people who remitted from depression.

METHODS

This randomized, double-blind crossover study involved 12 participants, 5 with remitted major depressive disorder (rMDD) and 7 healthy controls (HC), who received an injection of typhoid vaccine and placebo (or vice-versa) intramuscularly at least one week apart. At baseline and between 4 and 6 h post-injection on both days, participant mood was measured using the profile of mood states (POMS), and injection blood samples were collected for cytokines measurement. All participants completed the Effort Expenditure for Rewards Task (EEfRT), a behavioral paradigm measuring effort-based decision-making before and 4 h post-both injections. Generalized linear mixed modeling was used to evaluate group differences in choosing the hard over easy task to obtain a monetary reward.

RESULTS

Typhoid vaccine increased IL-6 in all participants. On the EEfRT, a significant interaction between treatment condition (typhoid vs. placebo) and participant group (HC vs. rMDD) was found (p = .004). Analyses of simple effects within treatment conditions found that after placebo, HCs were more likely to choose the harder task than rMDD (OR = 3.21; p = .013). However, after the typhoid vaccine, no differences were found between rMDD and HC (p = .397). Analyses within participant groups found that the probability of choosing a hard task was higher after placebo for HC (OR = 1.37; p = .045), but not different within rMDD (p = .241). For HC at baseline, mood was significantly lower following injection with typhoid vaccine, relative to placebo (b = -1.03, p < .001); however, this effect should be considered coincidental, given that mood rating was taken prior to injection. For rMDD patients 4-6 h post-injection, mood was significantly lower following typhoid vaccine, relative to placebo (b = -0.981, p < .001 b = -0.77, p < .001). Finally, for HC receiving placebo, mood was significantly lower 4-6 h post-injection, relative to baseline (b = -1.76, p < .001).

CONCLUSIONS

Our preliminary findings suggest persistent deficits in motivational reward processing function despite clinical improvement in remitted depressed patients.

Typhoid vaccine does not impact feelings of social connection or social behavior in a randomized crossover trial among middle-aged female breast cancer survivors

BACKGROUND

Inflammation can have social consequences, which may be relevant to inflammation's link with depression. The current study tests whether a typhoid vaccine increases feelings of social disconnection and avoidance behavior.

METHOD

In two full-day visits at least three weeks apart, 172 postmenopausal breast cancer survivors (Stage I-IIIA) each received a typhoid capsular polysaccharide vaccination and a saline placebo injection in a random sequence. Blood was drawn prior to the injection, as well as every 90 min thereafter for 8 h to assess the inflammatory response (interleukin-6, IL-6; interleukin-1 receptor antagonist, IL-1Ra). At both visits, women completed the Social Connection Scale at 0 and 8.5 h post-vaccination as well as implicit and explicit social avoidance tasks at 7 h post-vaccination.

RESULTS

The typhoid vaccine triggered rises in both inflammatory markers (ps < 0.01), but it did not impact feelings of social connection (p = .32), or performance on the implicit (p = .34) or explicit tasks (p = .37). Inflammatory rises did not predict feelings of social connection (ps > 0.64) or performance on explicit (ps > 0.73) or implicit (ps > 0.88) social avoidance tasks.

CONCLUSION

Milder inflammatory stimuli may not affect social processes. Higher levels of inflammation or, relatedly, more sickness symptoms may be necessary to recapitulate prior findings of social avoidance.

Everyday co-presence with a romantic partner is associated with lower C-reactive protein

Social relationships are an important driver of health, and inflammation has been proposed as a key neurobiological mechanism to explain this effect. Behavioral researchers have focused on social relationship quality to further explain the association, yet recent research indicates that relationship quality may not be as robust a predictor as previously thought. Here, building on animal models of social bonds and recent theory on close relationships, we instead investigated merely being in the physical presence of one's romantic partner. Specifically, we tested the hypothesis that spending more time co-present with a loved partner in everyday life would be associated with lower C-reactive protein (CRP). Three times over the course of one month, 100 people in romantic relationships reported how much time they spent in the same physical space as their partner in the prior 24 h, in minutes, and provided a sample of blood for CRP assay (n observations = 296). Results from multi-level models showed that when one reported spending more time in the physical presence of their partner they had lower CRP - an effect that was independent from social relationship quality explanations from the prior literature, including romantic relationship quality, hostility, and loneliness. These findings move past global assessments of social isolation to consider a novel everyday behavior that is of great interest in the non-human animal literature - spending time together -- as a potential mechanism linking high-quality relationships and physical health in adult humans. The findings also point to future research on additional behavioral mechanisms that are not dependent on stress pathways: people in high-quality relationships tend to spend enjoyable and affectionate time with one another, which may impact inflammation.

Breast cancer survivors' typhoid vaccine responses: Chemotherapy, obesity, and fitness make a difference

PURPOSE

To investigate breast cancer survivors' inflammatory responses to typhoid vaccine as a window into their innate immune response to novel pathogens.

METHODS

This double-blind crossover trial randomized 158 breast cancer survivors to either the vaccine/saline placebo or the placebo/vaccine sequence. The relative contributions of age, cardiorespiratory fitness (VO_2peak), type of cancer treatment, central obesity, and depression to interleukin (IL)-6, IL-1 receptor antagonist (IL-1Ra), and WBC vaccine responses were assessed pre-injection and 1.5, 3, 4.5, 6, and 7.5 h post-injection.

RESULTS

The vaccine produced larger IL-6, IL-1Ra, and WBC responses than placebo, ps < 0.0001. Prior chemotherapy, higher central obesity, and lower VO_2peak were associated with smaller vaccine responses after controlling for baseline inflammation. Vaccine response was summarized by the percent increase in area under the curve (IL-6, WBC) or average post-injection mean (IL-1Ra) for vaccine relative to placebo. Women who received chemotherapy had smaller vaccine responses than women who did not for both IL-6 (44% vs 78%, p <.001) and WBC (26% vs 40%, p <.001); IL-1ra response was not significantly moderated by chemotherapy. Women whose central adiposity was one standard deviation above the mean had smaller vaccine responses than women with average adiposity for IL-6 (33% vs 54%, p <.001), WBC (20% vs 30%, p <.001), and IL-1Ra (2.0% vs 3.2%, p <.001). Women with an average level of VO_2peak had smaller vaccine responses than women whose VO_2peak was one standard deviation above the mean for IL-6 (54% vs 73%, p <.001), WBC (30% vs 40%, p <.001), and IL-1Ra (3.2% vs. 4.1%, p = 0.01). Age and depression did not significantly moderate vaccine responses.

CONCLUSIONS

This study provided novel data on chemotherapy's longer-term adverse immune consequences. The data also have an important public health message: even relatively low levels of fitness can benefit the innate immune response to a vaccine.

Dynamic Immune/Inflammation Precision Medicine: The Good and the Bad Inflammation in Infection and Cancer

Normal or “good” inflammation process starts from a local cellular response against injury or any infectious agent, with the activation of neutrophils, macrophages, Langerhans cells, dendritic cells, and innate immune cells. Cytokines and chemokines are produced to amplify the local inflammatory process followed by the migration of immune cells to the regional lymph nodes where adaptive immune response is initiated. Systemic inflammation enhances the biological response to mobilize additional cells from central and peripheral immune/hematopoietic system. Local mechanisms to limit inflammation are initiated and lead to healing. During the normal inflammatory process, there is a balance between the production of inflammatory chemokines/cytokines such as Tumor Necrosis Factor (TNF)-α, interleukin (IL)-6 and IL-1 and the production of compounds that limit inflammation and have an immune suppressive effect, such as IL-10 and Transforming Factor (TGF) β. IL-6 and IL-6/soluble IL-6 Receptor (R) complex stimulate liver cells to produce inflammatory proteins, which represents the systemic inflammation response. The magnitude and the duration of the systemic inflammatory response are linked to the cause, under genetic and epigenetic control. Significant inflammation as seen in septic shock, in severe forms of infections or in certain active cancers, represents the “bad inflammation”, correlated with a poor prognosis. In addition, the persistence of a chronic smoldering inflammation may lead to pathological situations which are observed in the majority of inflammatory, degenerative, dysmetabolic, or dysimmune diseases and cancer. Chronic smoldering inflammation is a cross between different pathological situations possibly linked. In addition, within the tumor microenvironment, inflammatory process results from different cellular mechanisms modulated by metabolic and vascular changes. On the contrary, a limited and balanced inflammation initiates the normal immune response, including the adaptive response which amplifies any immunotherapy, including vaccines. Immune checkpoint inhibitors and chimeric antigen receptor (CAR) T-cells are associated with cytokine release syndrome, a clinical risk leading to the use of anti-cytokine drugs. Nowadays, it is time to monitor the dynamic inflammatory process for a better immune precision medicine in both infections and cancer.

Loneliness in healthy young adults predicts inflammatory responsiveness to a mild immune challenge in vivo

The established link between loneliness and poor health outcomes may stem from aberrant inflammatory regulation. The present study tested whether loneliness predicted the inflammatory response to a standardised in vivo immune challenge. Using a within-subjects double blind placebo-controlled design, 40 healthy men (mean age = 25, SD = 5) received a Salmonella Typhi vaccination (0.025 mg; Typhim Vi, Sanofi Pasteur, UK) and placebo (saline) on two separate occasions. Loneliness was assessed using the R-UCLA loneliness scale. Regression analyses showed that those that reported feeling more lonely exhibited an elevated interleukin-6 response (β = 0.564, 95% confidence interval [0.003, 0.042], p < .05). This association withstood adjustment for potentially confounding variables, including age, sleep quality, socio-emotional factors, and health factors. The present findings are in line with evidence that loneliness may shift immune system responsivity, suggesting a potential biobehavioural pathway linking loneliness to impaired health.

Selective effects of acute low-grade inflammation on human visual attention

Illness is often accompanied by perceived cognitive sluggishness, a symptom that may stem from immune system activation. The current study used electroencephalography (EEG) to assess how inflammation affected three different distinct attentional processes: alerting, orienting and executive control. In a double-blinded placebo-controlled within-subjects design (20 healthy males, mean age = 24.5, SD = 3.4), Salmonella typhoid vaccination (0.025 mg; Typhim Vi, Sanofi Pasteur) was used to induce transient mild inflammation, while a saline injection served as a placebo-control. Participants completed the Attention Network Test with concurrent EEG recorded 6 h post-injection. Analyses focused on behavioral task performance and on modulation of oscillatory EEG activity in the alpha band (9-12 Hz) for alerting as well as orienting attention and frontal theta band (4-8 Hz) for executive control. Vaccination induced mild systemic inflammation, as assessed by interleukin-6 (IL-6) levels. While no behavioral task performance differences between the inflammation and placebo condition were evident, inflammation caused significant alterations to task-related brain activity. Specifically, inflammation produced greater cue-induced suppression of alpha power in the alerting aspect of attention and individual variation in the inflammatory response was significantly correlated with the degree of alpha power suppression. Notably, inflammation did not affect orienting (i.e., alpha lateralization) or executive control (i.e., frontal theta activity). These results reveal a unique neurophysiological sensitivity to acute mild inflammation of the neural network that underpins attentional alerting functions. Observed in the absence of performance decrements, these novel findings suggest that acute inflammation requires individuals to exert greater cognitive effort when preparing for a task in order to maintain adequate behavioral performance.

The co-injection of antioxidants with foot-and-mouth disease vaccination altered growth performance and blood parameters of finishing Holstein steers

Objective

This study was conducted to evaluate whether the co-injection of antioxidants together with foot-and-mouth disease (FMD) vaccination has the potential to attenuate the negative effects caused by vaccination in Holstein finishing steers.

Methods

A total of 36 finishing Holstein steers (body weight [BW]: 608±45.6 kg, 17 months old) were randomly allocated to one of three treatments: i) control (CON, only FMD vaccination without any co-injection), ii) co-injection of commercial non-steroidal anti-inflammatory drugs (NSAID) with FMD vaccination at a ratio of 10:1 (NSAID vol/FMD vaccine vol) as a positive control (PCON), iii) co-injection of commercial mixture of vitamin E and selenium with FMD vaccination (VITESEL) (1 mL of FMD vaccine+1 mL of antioxidants per 90 kg of BW). Changes in growth performance and blood parameters because of treatments were determined.

Results

No significant difference in BW, average daily gain, and dry matter intake of the steers was observed among the treatments. The FMD vaccination significantly increased white blood cells (WBC), neutrophils, platelets, and mean platelet volume (p<0.01) in blood analysis. The count of lymphocyte tended to increase after vaccination (p = 0.08). In blood analysis, steers in VITESEL tended to have higher numbers of WBC, neutrophils, and platelets compared to that of other treatments (p = 0.09, 0.06, and 0.09, respectively). Eosinophils in VITESEL were higher than those in PCON (p<0.01). Among blood metabolites, blood urea nitrogen and aspartate transaminase were significantly increased, but cholesterol, alanine transferase, inorganic phosphorus, Mg, and albumin were decreased after FMD vaccination (p<0.01).

Conclusion

The use of antioxidants in FMD vaccination did not attenuate growth disturbance because of FMD vaccination. The metabolic changes induced by vaccination were not controlled by the administration of antioxidants. The protective function of antioxidants was effective mainly on the cell counts of leukocytes.

The role of inflammation in core features of depression: Insights from paradigms using exogenously-induced inflammation

A wealth of evidence has implicated inflammation in the development of depression. Yet, the heterogeneous nature of depression has impeded efforts to understand, prevent, and treat the disease. The purpose of this integrative review is to summarize the connections between inflammation and established core features of depression that exhibit more homogeneity than the syndrome itself: exaggerated reactivity to negative information, altered reward processing, decreased cognitive control, and somatic syndrome. For each core feature, we first provide a brief overview of its relevance to depression and neurobiological underpinnings, and then review evidence investigating a potential role of inflammation. We focus primarily on findings from experimental paradigms of exogenously-induced inflammation. We conclude that inflammation likely plays a role in exaggerated reactivity to negative information, altered reward reactivity, and somatic symptoms. There is less evidence supporting an effect of inflammation on cognitive control as assessed by standard neuropsychological measures. Finally, we discuss implications for future research and recommendationsfor how to test the role of inflammation in the pathogenesis of heterogeneous psychiatric disorders.

Low-grade inflammation decreases emotion recognition - Evidence from the vaccination model of inflammation

The ability to adequately interpret the mental state of another person is key to complex human social interaction. Recent evidence suggests that this ability, considered a hallmark of 'theory of mind' (ToM), becomes impaired by inflammation. However, extant supportive empirical evidence is based on experiments that induce not only inflammation but also induce discomfort and sickness, factors that could also account for temporary social impairment. Hence, an experimental inflammation manipulation was applied that avoided this confound, isolating effects of inflammation and social interaction. Forty healthy male participants (mean age = 25, SD = 5 years) participated in this double-blind placebo-controlled crossover trial. Inflammation was induced using Salmonella Typhi vaccination (0.025 mg; Typhim Vi, Sanofi Pasteur, UK); saline-injection was used as a control. About 6 h 30 m after injection in each condition, participants completed the Reading the Mind in the Eyes Test (RMET), a validated test for assessing how well the mental states of others can be inferred through observation of the eyes region of the face. Vaccination induced systemic inflammation, elevating IL-6 by +419% (p < .001), without fever, sickness symptoms (e.g., nausea, light-headedness), or mood changes (all p's > .21). Importantly, compared to placebo, vaccination significantly reduced RMET accuracy (p < .05). RMET stimuli selected on valence (positive, negative, neutral) provided no evidence of a selective impact of treatment. By utilizing an inflammation-induction procedure that avoided concurrent sicknesses or symptoms in a double-blinded design, the present study provides further support for the hypothesis that immune activation impairs ToM. Such impairment may provide a mechanistic link explaining social-cognitive deficits in psychopathologies that exhibit low-grade inflammation, such as major depression.

Differential Effects of Inflammatory and Psychosocial Stress on Mood, Hypothalamic-Pituitary-Adrenal Axis, and Inflammation in Remitted Depression

BACKGROUND/AIMS

Major depressive disorder (MDD) is highly recurrent. This may be due to increased stress sensitivity after remission. Both inflammatory and psychosocial stressors are implicated in the pathogenesis of MDD, but the additive or differential effect is unclear.

METHODS

We conducted a single-blind placebo-controlled study to investigate the effects of inflammatory stress (i.e., typhoid vaccination), psychosocial stress (i.e., Trier Social Stress Test [TSST]), or a combination of both in women (25-45 years old) with (partially) remitted recurrent MDD (n = 21) and healthy female controls (n = 18). We evaluated the effect on mood measured by the Profile of Mood States, markers of the hypothalamic-pituitary-adrenal (HPA) axis activity, and inflammatory system activation. The study was performed during 2 testing days, separated by a washout of 7-14 days. In a crossover design, subjects received one of the interventions on one day and placebo on the other.

RESULTS

A lowering of mood was seen in patients (β [95% CI] = -4.79 [-6.82 to -2.75], p < 0.001) only after vaccination, but not after the TSST or the combination; this effect was not observed in controls. Controls experienced a significantly different response on adrenocorticotropic hormone (ACTH) after vaccination, with a general rise in ACTH not observed in patients. In both groups, the TSST activated the HPA axis and suppressed the inflammatory parameters.

CONCLUSIONS

There is a differential effect of inflammatory and psychosocial stress on mood and HPA axis activation in patients with remitted recurrent MDD. This may be an interesting treatment target in MDD.

Different Adjuvants Induce Common Innate Pathways That Are Associated with Enhanced Adaptive Responses against a Model Antigen in Humans

To elucidate the role of innate responses in vaccine immunogenicity, we compared early responses to hepatitis B virus (HBV) surface antigen (HBsAg) combined with different Adjuvant Systems (AS) in healthy HBV-naïve adults, and included these parameters in multi-parametric models of adaptive responses. A total of 291 participants aged 18–45 years were randomized 1:1:1:1:1 to receive HBsAg with AS01_B, AS01_E, AS03, AS04, or Alum/Al(OH)₃ at days 0 and 30 (ClinicalTrials.gov: NCT00805389). Blood protein, cellular, and mRNA innate responses were assessed at early time-points and up to 7 days after vaccination, and used with reactogenicity symptoms in linear regression analyses evaluating their correlation with HBs-specific CD4⁺ T-cell and antibody responses at day 44. All AS induced transient innate responses, including interleukin (IL)-6 and C-reactive protein (CRP), mostly peaking at 24 h post-vaccination and subsiding to baseline within 1–3 days. After the second but not the first injection, median interferon (IFN)-γ levels were increased in the AS01_B group, and IFN-γ-inducible protein-10 levels and IFN-inducible genes upregulated in the AS01 and AS03 groups. No distinct marker or signature was specific to one particular AS. Innate profiles were comparable between AS01_B, AS01_E, and AS03 groups, and between AS04 and Alum groups. AS group rankings within adaptive and innate response levels and reactogenicity prevalence were similar (AS01_B ≥ AS01_E > AS03 > AS04 > Alum), suggesting an association between magnitudes of inflammatory and vaccine responses. Modeling revealed associations between adaptive responses and specific traits of the innate response post-dose 2 (activation of the IFN-signaling pathway, CRP and IL-6 responses). In conclusion, the ability of AS01 and AS03 to enhance adaptive responses to co-administered HBsAg is likely linked to their capacity to activate innate immunity, particularly the IFN-signaling pathway.

Evaluation of the potential effects of AS03-adjuvanted A(H1N1)pdm09 vaccine administration on the central nervous system of non-primed and A(H1N1)pdm09-primed cotton rats

An increased risk of narcolepsy following administration of an AS03-adjuvanted A(H1N1)pdm09 pandemic influenza vaccine (Pandemrix™) was described in children and adolescents in certain European countries. We investigated the potential effects of administration of the AS03-adjuvanted vaccine, non-adjuvanted vaccine antigen and AS03 Adjuvant System alone, on the central nervous system (CNS) in one-month-old cotton rats. Naïve or A(H1N1)pdm09 virus-primed animals received 2 or 3 intramuscular injections, respectively, of test article or saline at 2-week intervals. Parameters related to systemic inflammation (hematology, serum IL-6/IFN-γ/TNF-α) were assessed. Potential effects on the CNS were investigated by histopathological evaluation of brain sections stained with hematoxylin-and-eosin, or by immunohistochemical staining of microglia, using Iba1 and CD68 as markers for microglia identification/activation, albumin as indicator of vascular leakage, and hypocretin. We also determined cerebrospinal fluid (CSF) hypocretin levels and hemagglutination-inhibiting antibody titers. Immunogenicity of the AS03-adjuvanted A(H1N1)pdm09 pandemic influenza vaccine was confirmed by the induction of hemagglutination-inhibiting antibodies. Both AS03-adjuvanted vaccine and AS03 alone activated transient innate (neutrophils/eosinophils) immune responses. No serum cytokines were detected. CNS analyses revealed neither microglia activation nor inflammatory cellular infiltrates in the brain. No differences between treatment groups were detected for albumin extravascular leakage, CSF hypocretin levels, numbers of hypocretin-positive neuronal bodies or distributions of hypocretin-positive axonal/dendritic projections. Consequently, there was no evidence that intramuscular administration of the test articles promoted inflammation or damage in the CNS, or blood-brain barrier disruption, in this model.

Effects of typhoid vaccine on inflammation and sleep in healthy participants: a double-blind, placebo-controlled, crossover study

RATIONALE

An increasing body of evidence links the occurrence of sleep continuity disturbances with increased inflammation and both sleep disturbances and inflammation are associated with clinical depression. Typhoid vaccination results in a mild inflammatory response that significantly increases levels of the proinflammatory cytokine, interleukin (IL)-6.

OBJECTIVES

The present exploratory study aimed to enhance our understanding of the link between inflammation, sleep and depression by examining the effects of typhoid vaccine on the sleep polysomnogram.

METHODS

We studied the effects of a single injection of typhoid polysaccharide vaccine and placebo (saline solution) on sleep in 16 healthy male and female participants aged 20-38 years, sleeping at home in a randomized, double-blind, balanced order, crossover design. Subjective measures of mood, sleep and adverse effects were elicited and plasma samples analysed for IL-6 levels.

RESULTS

IL-6 levels (in picogramme per millilitre) significantly increased 2 h post vaccine compared to placebo (0.90 vs 0.53, p = 0.026, r = 0.55). Relative to placebo, typhoid vaccination produced significant impairment in several measures of sleep continuity. Total sleep time (in minute) (426.1 vs 410.7, p = 0.005, r = 0.62) and sleep efficiency percent (94.3 vs 91.5, p = 0.007, r = 0.65) were decreased; with increases in wake after sleep onset (in minute) (25.5 vs 38.8, p = 0.007,r = 0.65), total wake (in minute) (34.9 vs 50.3, p = 0.005,r = 0.67), sleep stage transitions (155.9 vs 173.1, p = 0.026, r = 0.56), number of awakenings (27.2 vs 36.1, p = 0.007, r = 0.64) and awakening index (3.8 vs 5.3, p = 0.005, r = 0.67) (means, significance level and effect size).

CONCLUSIONS

Inflammatory mechanisms may underlie the impairment in sleep efficiency which is a hallmark of major depression. Because impaired sleep is also a predictor of major depression, there may be a role for suitable anti-inflammatory approaches in strategies designed to prevent the onset of depression. ClinicalTrials.gov ( http://www.clinicaltrials.gov ): NCT02628054.

C-reactive protein levels following hepatitis B vaccine in healthy newborns

OBJECTIVE

Evaluate the effect of Hepatitis B vaccine (HepB) on C-reactive protein (CRP) levels in healthy term infants.

STUDY DESIGN

A prospective controlled study in an academic medical center serving an inner city community. Subjects were singleton, term and late pre-term infants delivered vaginally with normal physical examination and without risk factors for or signs of sepsis. CRP levels were measured in cord blood and at the time of newborn genetic screening. The early HepB group received HepB within a few hours after birth. The late HepB group had HepB delayed until after the repeat CRP.

RESULT

One hundred and eighty-two infants were enrolled (94 early HepB, 88 late HepB) with similar demographic features in each group. Neither the mean cord CRP (early HepB, 0.24±0.23 vs late HepB, 0.30±0.68 mg l(-1), P=0.37) nor the median of the repeat CRP (early HepB, 2.6 (interquartile range, 1.18 to 7.03) vs late HepB, 1.7 (interquartile range, 0.73 to 5.8) mg l(-1), P=0.14) showed significant differences between the two groups.

CONCLUSION

HepB does not affect CRP levels in healthy term infants.

Potential Use of Salivary Markers for Longitudinal Monitoring of Inflammatory Immune Responses to Vaccination

Vaccination, designed to trigger a protective immune response against infection, is a trigger for mild inflammatory responses. Vaccination studies can address the question of inflammation initiation, levels, and resolution as well as its regulation for respective studied pathogens. Such studies largely based on analyzing the blood components including specific antibodies and cytokines were usually constrained by number of participants and volume of collected blood sample. Hence, blood-based studies may not be able to cover the full dynamic range of inflammation responses induced by vaccination. In this review, the potential of using saliva in addition to blood for studying the kinetics of inflammatory response studies was assessed. Saliva sampling is noninvasive and has a great potential to be used for studies aimed at analysing the magnitude, time course, and variance in immune responses, including inflammation after vaccination. Based on a literature survey of inflammatory biomarkers that can be determined in saliva and an analysis of how these biomarkers could help to understand the mechanisms and dynamics of immune reactivity and inflammation, we propose that the saliva-based approach might have potential to add substantial value to clinical studies, particularly in vulnerable populations such as infants, toddlers, and ill individuals.

Mycobacterium bovis BCG Vaccination Induces Divergent Proinflammatory or Regulatory T Cell Responses in Adults

Mycobacterium bovis bacillus Calmette-Guérin (BCG), the only currently available vaccine against tuberculosis, induces variable protection in adults. Immune correlates of protection are lacking, and analyses on cytokine-producing T cell subsets in protected versus unprotected cohorts have yielded inconsistent results. We studied the primary T cell response, both proinflammatory and regulatory T cell responses, induced by BCG vaccination in adults. Twelve healthy adult volunteers who were tuberculin skin test (TST) negative, QuantiFERON test (QFT) negative, and BCG naive were vaccinated with BCG and followed up prospectively. BCG vaccination induced an unexpectedly dichotomous immune response in this small, BCG-naive, young-adult cohort: BCG vaccination induced either gamma interferon-positive (IFN-γ(+)) interleukin 2-positive (IL-2(+)) tumor necrosis factor α-positive (TNF-α(+)) polyfunctional CD4(+) T cells concurrent with CD4(+) IL-17A(+) and CD8(+) IFN-γ(+) T cells or, in contrast, virtually absent cytokine responses with induction of CD8(+) regulatory T cells. Significant induction of polyfunctional CD4(+) IFN-γ(+) IL-2(+) TNF-α(+) T cells and IFN-γ production by peripheral blood mononuclear cells (PBMCs) was confined to individuals with strong immunization-induced local skin inflammation and increased serum C-reactive protein (CRP). Conversely, in individuals with mild inflammation, regulatory-like CD8(+) T cells were uniquely induced. Thus, BCG vaccination either induced a broad proinflammatory T cell response with local inflammatory reactogenicity or, in contrast, a predominant CD8(+) regulatory T cell response with mild local inflammation, poor cytokine induction, and absent polyfunctional CD4(+) T cells. Further detailed fine mapping of the heterogeneous host response to BCG vaccination using classical and nonclassical immune markers will enhance our understanding of the mechanisms and determinants that underlie the induction of apparently opposite immune responses and how these impact the ability of BCG to induce protective immunity to TB.

Negative affectivity predicts decreased pain tolerance during low-grade inflammation in healthy women

INTRODUCTION

Experimental animal studies provided evidence for a synergistic effect of immunological and psychological stressors on subsequent sickness behaviours. Up to now, little corroborating evidence for such synergy exists for humans, in whom it may provide a mechanism leading to the expression of functional somatic symptoms. The aim of the present study was to determine an interaction between stress(-vulnerability) and an immunological activation on experimental pain sensitivity, i.e., pressure pain threshold and tolerance in healthy humans.

METHODS

In healthy female participants (n=25, mean age 22.3 years), negative affectivity (NA) and experienced stress were assessed by questionnaire before receiving a Salmonella typhi vaccine or saline control in a randomized blinded cross-over design. Pressure pain threshold was assessed at the lower back and calves and pain tolerance was assessed at the thumbnail, before and six hours after each injection.

RESULTS

Vaccination induced leukocytosis (+100%) and increased serum IL-6 (+670%). NA predicted decreased pain tolerance after vaccination (β=-.57, p=.007), but not after placebo (β=.25, p=.26). Post-hoc analyses also demonstrated an association with administration order.

DISCUSSION

NA moderated the effects of inflammation on pain tolerance. This finding is consistent with a synergistic model whereby inflammation may lower the threshold for pain reporting in individuals with increased vulnerability for somatic symptom reporting.

Induced mild systemic inflammation is associated with impaired ability to improve cognitive task performance by practice

Elevated inflammatory levels are linked to poorer cognition, but experimental confirmation is lacking. This report examined associations between cognitive performance and inflammation induced by exercise and vaccination. Thirty-six (exercise N = 18, vaccination N = 18) healthy males completed a paced auditory serial addition test (PASAT), which is a multifaceted measure of cognitive function. The task was completed in placebo and elevated inflammation states. Improvements in PASAT performance were related to inflammation. In the exercise study, IL-6 during the first PASAT negatively correlated with PASAT improvement (p = .022). In the vaccination study, increases in C-reactive protein between PASATs correlated with reduced PASAT improvement (p < .001). Inflammation was linked to reduced improvements in cognitive performance. Further research should identify the specific cognitive functions affects and the underlying mechanisms.

Underlying inflammation has no impact on the oxidative stress response to acute mental stress

INTRODUCTION

Mental stress is considered to be a trigger for acute myocardial infarction (MI), with inflammation thought to provide a mechanism. Inflammation is reciprocally linked to oxidative stress, which has also been implicated in MI. The purpose of this study was to assess the effects of experimentally-induced inflammation on the oxidative stress response to mental stress in healthy participants.

METHODS

Healthy males undertook one of two inflammatory stimuli: typhoid vaccination (Vaccination paradigm, N=17) or eccentric exercise (Eccentric exercise paradigm, N=17). All participants completed a mental arithmetic stress task twice (within-subject design): 6h after the inflammatory stimulus, and during a control non-inflammation condition. Blood samples were taken before, immediately and 30min after the stress task. Plasma was assessed for interleukin-6 (IL-6), protein carbonyls (PC), lipid hydroperoxides (LOOH), total antioxidant capacity (TAC) and nitric oxide metabolites (NOx).

RESULTS

Vaccination paradigm: IL-6, PC and NOx were significantly higher in the vaccination condition, relative to the control condition (p<.05). PC, TAC, LOOH and NOx were unchanged in response to mental stress in both the vaccination and control conditions. Eccentric Exercise paradigm: IL-6 and TAC were significantly higher in the eccentric exercise condition (p<.05), relative to the control condition. PC, TAC and NOx were unchanged in response to mental stress in both the eccentric exercise and control conditions.

CONCLUSIONS

Two different inflammatory paradigms were successful in increasing selective plasma markers of inflammation and oxidative stress prior to a mental stress task. However, experimentally induced transient inflammation had no impact on mental stress-induced changes in plasma LOOH, PC, TAC or NOx in young healthy participants.

Vaccine-induced inflammation attenuates the vascular responses to mental stress

Inflammation is associated with poorer vascular function, with evidence to suggest that inflammation can also impair the vascular responses to mental stress. This study examined the effects of vaccine-induced inflammation on vascular responses to mental stress in healthy participants. Eighteen male participants completed two stress sessions: an inflammation condition having received a typhoid vaccination and a control (non-inflamed) condition. Tumor necrosis factor-alpha and interleukin-6 (p's<.001) increased following vaccination, confirming modest increases in inflammation. Mental stress increased blood flow, blood pressure, heart rate, and cardiac output in both conditions (all p's<.001), but the blood flow response to stress was attenuated having received the vaccination compared to the control condition (p's<.05). These results further implicate the interaction between inflammation and the vasculature as a mechanism through which stress may trigger myocardial infarction.

The Yin-Yang arms of vaccines: disease-fighting power versus tissue-destructive inflammation

The disease-fighting power of vaccines has defeated many pathogens and has been credited with global reduction of mortality and morbidity. However, most vaccine developments focus on the enhancement of effector responses with systemic inflammation and the consequences overlooked. Recent evidence shows that systemic inflammatory phenotypes, acute or chronic, are both detrimental and should be avoided if possible. Since noninvasive vaccination by painless delivery of nasal vaccines and skin patch vaccines could elicit potent protective immunity without inducing systemic inflammation, it can be predicted that vaccinology will increasingly see the abandonment of the 'needle-injection' paradigm for vaccine development. The findings that specific viral particles could rapidly remodel the tissue environment postinfection in favor of some pathogens with the capacity to suppress others illustrate the pressing need for a deeper understanding of the underlying mechanisms in order to unlock the full potential of immunological intervention.