Coix Seed Consumption Affects the Gut Microbiota and the Peripheral Lymphocyte Subset Profiles of Healthy Male Adults

A systematic examination of the effects of traditional herbal medicines including their mechanisms could allow for their effective use and provide opportunities to develop new medicines. Coix seed has been suggested to promote spontaneous regression of viral skin infection. Purified oil from coix seed has also been suggested to increase the peripheral CD4⁺ lymphocytes. We, herein, attempt to shed more light on the way through which coix seed affects the human systemic immune function by hypothesizing that a central role to these changes could be played through changes in the gut microbiota. To that end, healthy adult males (n = 19) were divided into two groups; 11 of them consumed cooked coix seed (160 g per day) for 7 days (intervention), while the other eight were given no intervention. One week of coix seed consumption lead to an increase of the intestinal Faecalibacterium abundance and of the abundance (as % presence of overall peripheral lymphocytes) of CD3⁺CD8⁺ cells, CD4⁺ cells, CD4⁺CD25⁺ cells, and naïve/memory T cell ratio. As the relationship of microbiota and skin infection has not been clarified, our findings could provide a clue to a mechanism through which coix seed could promote the spontaneous regression of viral skin infections.

Complementary Feeding: Recommendations for the Introduction of Allergenic Foods and Gluten in the Preterm Infant

Background: The aim of this systematic review is to analyze the available literature on the introduction of allergenic foods and gluten among preterm infants. Methods: A systematic review of published studies concerning the introduction of gluten and allergenic foods in preterm infants was performed on PubMed and on the Cochrane Library. Results: Of the 174 PubMed results, 15 papers were considered suitable for the review. A total of 83 records were identified through the Cochrane Library search; eight papers were included in the review. Additional papers were identified from the reference lists of included studies. A secondary search was conducted on the same databases to find recommendations and advice regarding healthy full-term infants that could be translated to preterm infants. Therefore, 59 additional papers were included in the review. Conclusions: Current guidelines for the introduction of solid food cannot be directly transposed to preterm infants. Further research is needed to provide evidence-based guidelines regarding weaning in preterm infants. To date, we can suggest that in preterm infants allergenic foods and gluten may be introduced when complementary feeding is started, any time after 4 months of corrected age, avoiding delayed introduction and irrespective of infants’ relative risk of developing allergy. Avoiding large amounts of gluten during the first few weeks after gluten introduction and during infancy is advised, despite limited evidence to support this recommendation.

Innate Immune Response to Fasting and Refeeding in the Zebrafish Kidney

Animals acquire nutrients and energy through feeding to achieve a balance between growth and organismal health. When there is a change in nutrient acquisition, the state of growth changes and may also cause changes in the intrinsic immune system. Compensatory growth (CG), a specific growth phenomenon, involves the question of whether changes in growth can be accompanied by changes in innate immunity. The zebrafish (Danio rerio), a well-known fish model organism, can serve as a suitable model. In this study, the zebrafish underwent 3 weeks of fasting and refeeding for 3 to 7 day periods. It was found that CG could be achieved in zebrafish. Zebrafish susceptibility to Streptococcus agalactiae increased after starvation. In addition, the amount of melano-macrophage centers increased after fasting and the proportion of injured tubules increased after refeeding for 3 and 5 days, respectively. Furthermore, the kidneys of zebrafish suffering from starvation were under oxidative stress, and the activity of several antioxidant enzymes increased after starvation, including catalase, glutathione peroxidases and superoxide dismutase. Innate immune parameters were influenced by starvation. Additionally, the activity of alkaline phosphatase and lysozyme increased after starvation. The mRNA expression of immune-related genes like il-1β was elevated to a different extent after fasting with or without lipopolysaccharides (LPS) challenge. This study showed that the function of the innate immune system in zebrafish could be influenced by nutrition status.

Obesity, COVID-19 and innate immunometabolism

As COVID-19 continues to spread worldwide, severe disease and mortality have been observed in obese patients. We discuss how obesity and obesity-associated factors such as ‘meta-flammation’, dietary fat intake and paradoxical suppression of the innate immune response within the pulmonary compartment may be crucial determinants in the host response to a novel viral pathogen. Modulation of immune cell bioenergetics and metabolic potential plays a central role in the innate immune response to infection, and as we strive to combat this new global health threat, immunometabolism of the innate immune system warrants attention.

The Effect of a Multivitamin and Mineral Supplement on Immune Function in Healthy Older Adults: A Double-Blind, Randomized, Controlled Trial

Older adults are at increased risk for vitamin and mineral deficiencies that contribute to age-related immune system decline. Several lines of evidence suggest that taking a multi-vitamin and mineral supplement (MVM) could improve immune function in individuals 55 and older. To test this hypothesis, we provided healthy older adults with either an MVM supplement formulated to improve immune function (Redoxon^® VI, Singapore) or an identical, inactive placebo control to take daily for 12 weeks. Prior to and after treatment, we measured (1) their blood mineral and vitamin status (i.e., vitamin C, zinc and vitamin D); (2) immune function (i.e., whole blood bacterial killing activity, neutrophil phagocytic activity, and reactive oxygen species production); (3) immune status (salivary IgA and plasma cytokine/chemokine levels); and (4) self-reported health status. MVM supplementation improved vitamin C and zinc status in blood and self-reported health-status without altering measures of immune function or status or vitamin D levels, suggesting that healthy older adults may benefit from MVM supplementation. Further development of functional assays and larger study populations should improve detection of specific changes in immune function after supplementation in healthy older adults. Clinical Trials Registration: ClinicalTrials.gov #NCT02876315.

Prevalence of food allergen and aeroallergen sensitization among children in Sichuan province

Food allergen and aeroallergen sensitization are common allergic diseases worldwide, with widely varying estimates of prevalence in children. Our study investigated the characteristics of ingestion and inhalation allergy among children from Sichuan province in Southwest China, so as to get public awareness of these disorders.A total of 1722 children between 0 and 14 years' old were enrolled in this study. They were outpatients in the West China Second University Hospital during June 2019 to September 2019. Serum specific IgE specific to 10 types of food allergen and 10 types of aeroallergen were estimated. Nutrition indicators were tested by electrochemical luminescence.59.70% children were allergic to at least 1 allergen, comprising 24.90% to aeroallergen and 38.81% to food allergen, respectively, whereas 36.28% children were allergic to both aeroallergen and food allergen. Milk was the most common food allergen, and egg came in second place. With regard to aeroallergen, house dust mite held the maximum proportion (65.02%), whereas dust mite followed behind. Inhalation allergy was more commonly seen in boys than girls. Bronchitis was the most common symptom of both allergies. In addition, the highest incidence age for children to be sensitive to food allergen and aeroallergen were 0∼2 years' old and 3∼5 years' old, respectively. It is worth mentioning that there was no significant difference in nutritional status between children with or without allergic diseases.Our findings reveal that milk, egg, house dust mite, and dust mite are the most common allergens among children in Sichuan province. Boys are more susceptible to aeroallergen than girls. Furthermore, the prevalence of ingestion and inhalation allergy varies from different age groups, and has no correlation with nutritional status. In brief, the analysis of the pattern of food allergen and aeroallergen sensitization is invaluable to effective diagnosis and treatment of allergic diseases.

Feeding-dependent VIP neuron-ILC3 circuit regulates the intestinal barrier

The intestinal mucosa serves both as a conduit for the uptake of food-derived nutrients and microbiome-derived metabolites, and as a barrier that prevents tissue invasion by microorganisms and tempers inflammatory responses to the myriad contents of the lumen. How the intestine coordinates physiological and immune responses to food consumption to optimize nutrient uptake while maintaining barrier functions remains unclear. Here we show in mice how a gut neuronal signal triggered by food intake is integrated with intestinal antimicrobial and metabolic responses that are controlled by type-3 innate lymphoid cells (ILC3)1-3. Food consumption rapidly activates a population of enteric neurons that express vasoactive intestinal peptide (VIP)4. Projections of VIP-producing neurons (VIPergic neurons) in the lamina propria are in close proximity to clusters of ILC3 that selectively express VIP receptor type 2 (VIPR2; also known as VPAC2). Production of interleukin (IL)-22 by ILC3, which is upregulated by the presence of commensal microorganisms such as segmented filamentous bacteria5-7, is inhibited upon engagement of VIPR2. As a consequence, levels of antimicrobial peptide derived from epithelial cells are reduced but the expression of lipid-binding proteins and transporters is increased8. During food consumption, the activation of VIPergic neurons thus enhances the growth of segmented filamentous bacteria associated with the epithelium, and increases lipid absorption. Our results reveal a feeding- and circadian-regulated dynamic neuroimmune circuit in the intestine that promotes a trade-off between innate immune protection mediated by IL-22 and the efficiency of nutrient absorption. Modulation of this pathway may therefore be effective for enhancing resistance to enteropathogens2,3,9 and for the treatment of metabolic diseases.

High Glucose Intake Exacerbates Autoimmunity through Reactive-Oxygen-Species-Mediated TGF-β Cytokine Activation

Diet has been suggested to be a potential environmental risk factor for the increasing incidence of autoimmune diseases, yet the underlying mechanisms remain elusive. Here, we show that high glucose intake exacerbated autoimmunity in mouse models of colitis and experimental autoimmune encephalomyelitis (EAE). We elucidated that high amounts of glucose specifically promoted T helper-17 (Th17) cell differentiation by activating transforming growth factor-β (TGF-β) from its latent form through upregulation of reactive oxygen species (ROS) in T cells. We further determined that mitochondrial ROS (mtROS) are key for high glucose-induced TGF-β activation and Th17 cell generation. We have thus revealed a previously unrecognized mechanism underlying the adverse effects of high glucose intake in the pathogenesis of autoimmunity and inflammation.

Ingestion of killed bacteria activates antimicrobial peptide genes in Drosophila melanogaster and protects flies from septic infection

Drosophila melanogaster possesses a sophisticated and effective immune system composed of humoral and cellular immune responses, and production of antimicrobial peptides (AMPs) is an important defense mechanism. Expression of AMPs is regulated by the Toll and IMD (immune deficiency) pathways. Production of AMPs can be systemic in the fat body or a local event in the midgut and epithelium. So far, most studies focus on systemic septic infection in adult flies and little is known about AMP gene activation after ingestion of killed bacteria. In this study, we investigated activation of AMP genes in the wild-type w¹¹¹⁸, MyD88 and Imd mutant flies after ingestion of heat-killed Escherichia coli and Staphylococcus aureus. We showed that ingestion of E. coli activated most AMP genes, including drosomycin and diptericin, in the first to third instar larvae and pupae, while ingestion of S. aureus induced only some AMP genes in some larval stages or in pupae. In adult flies, ingestion of killed bacteria activated AMP genes differently in males and females. Interestingly, ingestion of killed E. coli and S. aureus in females conferred resistance to septic infection by both live pathogenic Enterococcus faecalis and Pseudomonas aeruginosa, and ingestion of E. coli in males conferred resistance to P. aeruginosa infection. Our results indicated that E. coli and S. aureus can activate both the Toll and IMD pathways, and systemic and local immune responses work together to provide Drosophila more effective protection against infection.

Effect of Epicutaneous Immunotherapy vs Placebo on Reaction to Peanut Protein Ingestion Among Children With Peanut Allergy: The PEPITES Randomized Clinical Trial

IMPORTANCE

There are currently no approved treatments for peanut allergy.

OBJECTIVE

To assess the efficacy and adverse events of epicutaneous immunotherapy with a peanut patch among peanut-allergic children.

DESIGN, SETTING, AND PARTICIPANTS

Phase 3, randomized, double-blind, placebo-controlled trial conducted at 31 sites in 5 countries between January 8, 2016, and August 18, 2017. Participants included peanut-allergic children (aged 4-11 years [n = 356] without a history of a severe anaphylactic reaction) developing objective symptoms during a double-blind, placebo-controlled food challenge at an eliciting dose of 300 mg or less of peanut protein.

INTERVENTIONS

Daily treatment with peanut patch containing either 250 μg of peanut protein (n = 238) or placebo (n = 118) for 12 months.

MAIN OUTCOMES AND MEASURES

The primary outcome was the percentage difference in responders between the peanut patch and placebo patch based on eliciting dose (highest dose at which objective signs/symptoms of an immediate hypersensitivity reaction developed) determined by food challenges at baseline and month 12. Participants with baseline eliciting dose of 10 mg or less were responders if the posttreatment eliciting dose was 300 mg or more; participants with baseline eliciting dose greater than 10 to 300 mg were responders if the posttreatment eliciting dose was 1000 mg or more. A threshold of 15% or more on the lower bound of a 95% CI around responder rate difference was prespecified to determine a positive trial result. Adverse event evaluation included collection of treatment-emergent adverse events (TEAEs).

RESULTS

Among 356 participants randomized (median age, 7 years; 61.2% male), 89.9% completed the trial; the mean treatment adherence was 98.5%. The responder rate was 35.3% with peanut-patch treatment vs 13.6% with placebo (difference, 21.7% [95% CI, 12.4%-29.8%; P < .001]). The prespecified lower bound of the CI threshold was not met. TEAEs, primarily patch application site reactions, occurred in 95.4% and 89% of active and placebo groups, respectively. The all-causes rate of discontinuation was 10.5% in the peanut-patch group vs 9.3% in the placebo group.

CONCLUSIONS AND RELEVANCE

Among peanut-allergic children aged 4 to 11 years, the percentage difference in responders at 12 months with the 250-μg peanut-patch therapy vs placebo was 21.7% and was statistically significant, but did not meet the prespecified lower bound of the confidence interval criterion for a positive trial result. The clinical relevance of not meeting this lower bound of the confidence interval with respect to the treatment of peanut-allergic children with epicutaneous immunotherapy remains to be determined.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02636699.

Effects of food availability on growth performance and immune-related gene expression of juvenile olive flounder (Paralichthys olivaceus)

Unfavorable environmental conditions and inappropriate culture practices have increased the vulnerability of cultured fish to disease infection. Up to date many studies have aimed to determine a feeding regimen to maximize productivity; however, very little information on immune responses of cultured fish in response to underfeeding or overfeeding is available. Therefore, a preliminary study was conducted to evaluate effects of graded feeding levels (i.e., food availability) on growth performance and immune-related gene expression of juvenile olive flounder (Paralichthys olivaceus). Six different feeding rates including 1, 4, 7, 10, 13, and 16% body weight per day (BW/d) were randomly assigned to three replicate tanks stocking 150 fish (average initial body weight: 0.27 ± 0.02 g; mean ± SD) per tank. A feeding trial lasted for two weeks. Based on the results of the weight gain, nutrient gain, and whole-body compositions and energy content, the feeding rate of 10%, 13%, and 16% BW/d resulted in high nutritional status, whereas the feeding rate of 1% and 4% BW/d resulted in low nutritional status. Intermediate nutritional status was observed at the feeding rate of 7% BW/d. In the given rearing conditions the optimum feeding rate resulting in the maximum growth was estimated to be 11.9% BW/d based on the quadratic broken-line regression model, chosen as the best-fit model among the tested models. Expression of immune-related genes including IL-8 and IgM was significantly down-regulated in the flounder fed at 1% BW/d in comparison to those fed at 7% BW/d. Interestingly, expression of these genes in the flounder fed at 10%, 13%, and 16% BW/d was relatively down-regulated in comparison to that of the flounder fed at 7% BW/d. Although no statistical difference was detected, overall response patterns of other immune-related genes, including TLR3, polymeric Ig receptor, lysozyme C-type, GPx, SOD, and Trx followed what IL-8 and IgM exhibited in response to the various feeding rates. Given the current challenges in aquaculture of the flounder our findings suggest to prohibit underfeeding or overfeeding (i.e., ad-libitum feeding) when culturing the young flounder.

Detection of new pathways involved in the acceptance and the utilisation of a plant-based diet in isogenic lines of rainbow trout fry

To meet the growing demand of fish feed for aquaculture, an increasing proportion of marine ingredients are being replaced by blends of plant products. However, the total replacement of marine ingredients in salmonid diets impairs fish performance. This is particularly true during the early fry stage and this stage is therefore considered of particular importance. In rainbow trout (RBT), the existence of a genetic variability to survive and grow with plant-based diets devoid of marine ingredients has now been proved, but the mechanisms behind are little studied especially at early stage. To investigate these, we analysed the whole transcriptome of three isogenic lines of RBT fry, which have similar growth when fed a marine resources-based diet (M diet) but which highly differ in their responses to a plant-based diet (V diet). Analysis of transcriptomes profiles revealed 1740, 1834 and 246 probes differentially expressed among the three genotypes when fed the V diet. The use of these lines led to the discovery of potential molecular markers linked to plant-based diet utilisation, some of them belonging to new pathways, never described before. An important number of genes was related to immunity, but further investigations are needed to better understand the difference between the genotypes in their immune status response to V diet exposure. Finally, differences in expression of genes related to feed intake and sensory perception among genotypes suggested that the mechanisms underlying the differences in growth on plant-based diet are closely linked to diet acceptance. Research on plants components affecting feed intake should be thus further explored.

Inhibiting Microglia Expansion Prevents Diet-Induced Hypothalamic and Peripheral Inflammation

Cell proliferation and neuroinflammation in the adult hypothalamus may contribute to the pathogenesis of obesity. We tested whether the intertwining of these two processes plays a role in the metabolic changes caused by 3 weeks of a high-saturated fat diet (HFD) consumption. Compared with chow-fed mice, HFD-fed mice had a rapid increase in body weight and fat mass and specifically showed an increased number of microglia in the arcuate nucleus (ARC) of the hypothalamus. Microglia expansion required the adequate presence of fats and carbohydrates in the diet because feeding mice a very high-fat, very low-carbohydrate diet did not affect cell proliferation. Blocking HFD-induced cell proliferation by central delivery of the antimitotic drug arabinofuranosyl cytidine (AraC) blunted food intake, body weight gain, and adiposity. AraC treatment completely prevented the increase in number of activated microglia in the ARC, the expression of the proinflammatory cytokine tumor necrosis factor-α in microglia, and the recruitment of the nuclear factor-κB pathway while restoring hypothalamic leptin sensitivity. Central blockade of cell proliferation also normalized circulating levels of the cytokines leptin and interleukin 1β and decreased peritoneal proinflammatory CD86 immunoreactive macrophage number. These findings suggest that inhibition of diet-dependent microglia expansion hinders body weight gain while preventing central and peripheral inflammatory responses due to caloric overload.

Diamine oxidase levels in different chronic urticaria phenotypes

BACKGROUND

Diamine oxidase (DAO) is a polyamine-degrading enzyme also implicated in histamine metabolism. Chronic urticaria (CU) has a wide spectrum of clinical presentations and causes. Anisakis sensitisation associated chronic urticaria (CU+) has been characterised as a phenotype with different clinical and immunological characteristics and possibly associated with previous acute parasitism. We aimed to analyse serum DAO levels in different CU phenotypes. We further analysed the possible association of DAO with fish eating habits.

METHODS

We studied 35 CU+ patients and 39 non-sensitised CU patients (CU-) as well as 19 controls. We analysed fish-eating frequency as well as fish intake associated exacerbation of CU (FIAE) or gastro-intestinal complaints (GI). DAO levels were further analysed with respect to lymphoproliferative responses, cytokine and specific IgE production.

RESULTS

DAO levels were not different between CU and controls, but were significantly higher in CU+ than in CU-. CU+ patients with FIAE had lower DAO levels, but no differences were detected in patients with GI. DAO levels correlated positively with oily and canned fish consumption in CU-. In CU+, DAO levels correlated positively with specific Anisakis IgE, percentages of proliferation in Anisakis stimulated peripheral blood lymphocytes, serum IL-2 and IL-6, but correlated negatively with mitogen stimulated TGF-β in supernatants.

CONCLUSIONS

DAO levels in CU depend on fish-eating habits and in CU+ on the amount of specific IgE production. In the CU+ phenotype, lower levels of DAO predispose to urticaria exacerbation after fish intake, probably due to a relative insufficient enteric availability of this enzyme.

Hypothalamic innate immune reaction in obesity

Findings from rodent and human studies show that the presence of inflammatory factors is positively correlated with obesity and the metabolic syndrome. Obesity-associated inflammatory responses take place not only in the periphery but also in the brain. The hypothalamus contains a range of resident glial cells including microglia, macrophages and astrocytes, which are embedded in highly heterogenic groups of neurons that control metabolic homeostasis. This complex neural-glia network can receive information directly from blood-borne factors, positioning it as a metabolic sensor. Following hypercaloric challenge, mediobasal hypothalamic microglia and astrocytes enter a reactive state, which persists during diet-induced obesity. In established mouse models of diet-induced obesity, the hypothalamic vasculature displays angiogenic alterations. Moreover, proopiomelanocortin neurons, which regulate food intake and energy expenditure, are impaired in the arcuate nucleus, where there is an increase in local inflammatory signals. The sum total of these events is a hypothalamic innate immune reactivity, which includes temporal and spatial changes to each cell population. Although the exact role of each participant of the neural-glial-vascular network is still under exploration, therapeutic targets for treating obesity should probably be linked to individual cell types and their specific signalling pathways to address each dysfunction with cell-selective compounds.

Growth, feed intake and immune responses of orange-spotted grouper (Epinephelus coioides) exposed to low infectious doses of ectoparasite (Cryptocaryon irritans)

To explore the effect of low-dose Cryptocaryon irritans infection on growth, feeding and antiparasitic immunity of orange-spotted grouper (Epinephelus coioides), this study utilized C. irritans at concentrations of 5500 theronts/fish (Group I, 1/10 of 96 h LC50) or 11,000 theronts/fish (Group II) to infect E. coioides weighing 38 g on average at week 0, 2 and 4, respectively. Food consumption was recorded daily; the fish were weighed weekly; serum immobilizing titer (SIT), and acid phosphatase (ACP), alkaline phosphatase (AKP), superoxide dismutase (SOD), lysozyme (LZM) activity were recorded every 2 weeks; the fish were treated with lethal dose (70,000 theronts/fish) of C. irritans in the 8th week and death number were recorded. The result shows that in the 1st week after the first infection, the fish's weight gain (WG), length gain (LG), and specific growth rate (SGR) dropped as parasite dose increased, and WG, SGR values were negative; while, after the 2nd and the 3rd infection, no significant differences were detected among the three groups. These results indicated that the 1st infection affected the fish most, while the following infections were protected by some immunity. In the 3rd, 7th, and 8th week, condition factor (CF) increased with the increased infectious dose, indicating that the parasite affected body length more than body weight. As the experiment went on, accumulated food consumption (AFC) of all three groups steadily grew (control > Group I > Group II). But on the 2nd day after the first infection, daily food consumption (DFC) of Group I and II significantly dropped, the decline of Group II was greater than that of Group I, DFC recovered in the following week, with Group I earlier than Group II. After the 2nd infection, DFC of Group I and II dropped again, Group II still dropped more than Group I, and both groups recovered on the 3rd day after infection. The 3rd infection caused no significant difference in week food consumption (WFC). These results indicated that a higher dose of infection causes a greater drop in FC and a slower recovery. Weekly feed conversion ratio (WFCR) values of Group I and II in the 1st week was negative; in the 2nd week, WFCR was lower in the group infected by a higher dose of parasite; while in the 3rd and following weeks, no significant pattern was observed. Accumulate feed conversion ratio (AFCR) dropped as the infectious dose increased (control > Group I > Group II), AFCR of Group I and II reached above 0 in the 2nd and 4th week, respectively. From the 4th week on, the inter-group AFCR of the 3 groups still took on a declining trend with the increased infectious dose but the gap became smaller. One week after the first infection, SIT of Group I and Group II were 0; one week after the 2nd infection, SIT reached up to 8 (Group I) and 16 (Group II) respectively; and after the 3rd infection, SIT further increased and peaked in the 7th week. When challenged by lethal dose of C. irritans, fish of all 3 groups began to die since the 3rd day after infection, and the final deaths were 14, 12 and 8 for the control group, Group I and Group II, respectively. ACP activity in the 1st, 5th, 7th but the 3rd week was higher in the experiment group than that in the control group, but no significant difference was detected between Group I and II throughout the experiment. AKP activity increased as the infectious dose increased, but the difference among the three groups gradually became less obvious in latter infections, and no significant difference can be detected in the end. SOD activity increased with infection dose at each time point, while both group I and group II had their SOD activities first increased and then decreased as times of infection increased. The LZM activity of the two infection groups increased as the infectious times increased. Combining the results on growth and feeding, we speculated that the fish's physiological condition stabilized after 3 rounds of infection. To sum up, low-dose infection by C. irritans can induce the fish's immunity, but at the cost of decreasing food intake, decreased food conversion, and lagged growth.

Mice lacking NKT cells but with a complete complement of CD8+ T-cells are not protected against the metabolic abnormalities of diet-induced obesity

The contribution of natural killer T (NKT) cells to the pathogenesis of metabolic abnormalities of obesity is controversial. While the combined genetic deletion of NKT and CD8(+) T-cells improves glucose tolerance and reduces inflammation, interpretation of these data have been complicated by the recent observation that the deletion of CD8(+) T-cells alone reduces obesity-induced inflammation and metabolic dysregulation, leaving the issue of the metabolic effects of NKT cell depletion unresolved. To address this question, CD1d null mice (CD1d(-/-)), which lack NKT cells but have a full complement of CD8(+) T-cells, and littermate wild type controls (WT) on a pure C57BL/6J background were exposed to a high fat diet, and glucose intolerance, insulin resistance, dyslipidemia, inflammation, and obesity were assessed. Food intake (15.5±4.3 vs 15.3±1.8 kcal/mouse/day), weight gain (21.8±1.8 vs 22.8±1.4 g) and fat mass (18.6±1.9 vs 19.5±2.1 g) were similar in CD1d(-/-) and WT, respectively. As would be expected from these data, metabolic rate (3.0±0.1 vs 2.9±0.2 ml O(2)/g/h) and activity (21.6±4.3 vs 18.5±2.6 beam breaks/min) were unchanged by NKT cell depletion. Furthermore, the degree of insulin resistance, glucose intolerance, liver steatosis, and adipose and liver inflammatory marker expression (TNFα, IL-6, IL-10, IFN-γ, MCP-1, MIP1α) induced by high fat feeding in CD1d(-/-) were not different from WT. We conclude that deletion of NKT cells, in the absence of alterations in the CD8(+) T-cell population, is insufficient to protect against the development of the metabolic abnormalities of diet-induced obesity.

Effect of dietary supplementation on resistance to experimental infection with Haemonchus contortus in Creole kids

The aim of the present study was to test the effect of dietary supplementation on resistance to experimental infection with Haemonchus contortus in Creole kids. One trial with three replicates involved a total of 154 female kids that were chosen from three successive cohorts of the Creole flock of INRA-Gardel in 2007. The kids were placed into four treatments according to the amount of concentrate they received: G0 (no concentrate and a quality Dichantium spp. hay ad libitum, HAY), G1 (HAY+100g commercial concentrate d(-1)), G2 (HAY+200 g commercial concentrate d(-1)), G3 (HAY+300 g commercial concentrate d(-1)). The G0-G3 groups were infected with a single dose of 10,000 H. contortus third stage larvae (L(3)) at Day 0 (D0). Each infected group was comprised of one half resistant and one half susceptible genetically indexed kids. The average breeding values on egg excretion at 11 months of age were distant of 0.70, 0.65, 0.61 and 0.61 genetic standard deviations in G0, G1, G2 and G3, respectively. The faecal egg count (FEC), packed cell volume (PCV), eosinophilia (EOSI) and dry matter intake (DMI) indices were monitored weekly until 42 days post-infection. Enzyme-linked immunosorbent assay was carried out on serum samples to determine the level of IgA anti-H. contortus L(3) crude extracts and adult excretion/secretion products (ESP). The 10,000 L(3) dose received by the kids induced a severe infection: 8000 eggs per gram at the FEC peak, a PCV less than 15% and mortality. Interestingly, the supplemented animals in G3 showed a higher level of EOSI but a lower level of IgA anti-L3 and IgA anti-ESP than non-supplemented animals (G0). Resistant and susceptible kids had significantly different FEC variations within the groups. Susceptible kids had a 1.6 times higher egg output than resistant kids in G0. This difference was not found in the supplemented groups. The results of this study showed that supplementary feeding improved resistance of Creole kids to H. contortus experimental infection.

Phosphorylation reduces the allergenicity of cow casein in children with selective allergy to goat and sheep milk

This study aimed to characterize the role of phosphorylation of caseins in selective allergy to goat milk (GM) and sheep milk (SM) in patients with good tolerance to cow milk (CM). We performed skin prick tests with milk and caseins from CM, GM, and SM and immunoblotting and specific immunoglobulin (Ig) E determinations with milk and casein from cow and GM and SM. Sensitization to milk and caseins from goat and sheep was demonstrated in all 3 patients by skin tests, determination of specific IgE, or both. Immunoblotting confirmed that GM/SM proteins but not CM proteins were involved in the allergic symptoms. IgE reacted with several protein bands from the caseins and milk extracts of both sheep and goat. Phosphorylation was involved in the different allergenicity of CM caseins. We report the implication of phosphorylation in the allergenicity of caseins involved in selective allergy to GM and SM.

Absence of macrophage inflammatory protein-1{alpha} does not impact macrophage accumulation in adipose tissue of diet-induced obese mice

Macrophages and T-lymphocytes are known to accumulate in the white adipose tissue (WAT) of obese mice and humans, but the factors that cause this infiltration are not yet determined. Chemokines, which attract leukocytes to inflammatory sites, are candidates for this process. Macrophage inflammatory protein-1alpha (MIP-1alpha) expression is significantly elevated in WAT of obese mice and humans and positively correlates with fasting plasma insulin, but its potential role in leukocyte recruitment to WAT is unknown. MIP-1alpha-deficient, heterozygous, and wild-type mice were fed a Western diet (WD) for 16 wk. Plasma lipids, adipose tissue mass, energy expenditure, food intake, liver triglyceride content, and inflammatory cytokine expression were not different among genotypes. Gene expression of macrophage markers F4/80 and CD68, as well as T-lymphocyte marker CD3epsilon was increased in perigonadal WAT of obese WD-fed mice but was not influenced by MIP-1alpha expression level. Immunohistochemical analysis of WAT also showed no effect of MIP-1alpha on macrophage content. Two related chemokines, MIP-1beta and RANTES, had reduced expression in obese male MIP-1alpha-deficient mice compared with wild-type controls (P < or = 0.05). In mice fed the WD for 6 wk, WAT macrophage content was unchanged; however, CD8+ T-lymphocytes accumulated to a lesser extent in the MIP-1alpha-null mice. Therefore, expression of MIP-1alpha, as well as that of MIP-1beta and RANTES, increases as a consequence of weight gain, but these chemokines may not be required for the recruitment of monocytes to WAT during diet-induced obesity in mice and may impact T-lymphocyte recruitment only at early time points after WD feeding.

Effects of daily intake of Lactobacillus paracasei strain KW3110 on Japanese cedar pollinosis

Japanese cedar pollinosis is an important contributor to allergic rhinitis in Japan. Lactobacillus may be useful as an immunomodulator and is used widely as a foodstuff. The purpose of the study was to examine the effects of daily intake of the Lactobacillus paracasei strain KW3110 in patients with cedar pollinosis. The effects of daily intake of KW3110 in patients with cedar pollinosis were investigated in 126 patients who received KW3110 or a placebo in a double-blind study. The study began 1 month before the start of the pollen season and lasted for 3 months. A significant reduction of nasal symptoms and the serum level of eosinophil cationic protein and improvement of quality of life scores occurred in the patients who received KW3110 when pollen scattering was low. However, the effects were limited during the peak period of pollen scattering. Intake of KW3110 may reduce allergic inflammation, but the effect is limited.

Purine receptor antagonist modulates serology and affective behaviors in lupus-prone mice: evidence of autoimmune-induced pain?

Neurologic and psychiatric (NP) manifestations are severe complications of systemic lupus erythematosus (SLE). As commonly seen in patients, spontaneous disease onset in the MRL/MpJ-Fas(lpr)/J (MRL-lpr) mouse model of NP-SLE is accompanied by increased autoantibodies, pro-inflammatory cytokines and behavioral dysfunction which precede neuroinflammation and structural brain lesions. The role of purinergic receptors in the regulation of immunity and behavior remains largely unexplored in the field of neuropsychiatry. To examine the possibility that purinoception is involved in the development of affective behaviors, the P2X purinoceptor antagonist, suramin, was administered to lupus-prone mice from 5 to 14 weeks of age. In addition to food and water measures, novel object and sucrose preference tests were performed to assess neophobic anxiety- and anhedonic-like behaviors. Enzyme-linked immunosorbant assays for anti-nuclear antibodies (ANA) and pro-inflammatory cytokines were employed in immunopathological analyses. Changes in dendritic morphology in the hippocampal CA1 region were examined by a Golgi impregnation method. Suramin significantly lowered serum ANA and prevented behavioral deficits, but did not prevent neuronal atrophy in MRL-lpr animals. In a new batch of asymptomatic mice, systemic administration of corticosterone was found to induce aberrations in CA1 dendrites, comparable to the "stress" of chronic disease. The precise mechanism(s) through which purine receptor inhibition exerted beneficial effects is not known. The present data supports the hypothesis that activation of the peripheral immune system induces nociceptive-related behavioral symptomatology which is attenuated by the analgesic effects of suramin. Hypercortisolemia may also initiate neuronal damage, and metabolic perturbations may underlie neuro-immuno-endocrine imbalances in MRL-lpr mice.

Active immunization against ghrelin decreases weight gain and alters plasma concentrations of growth hormone in growing pigs

Ghrelin has been implicated in the control of food intake and in the long-term regulation of body weight. We theorize that preventing the ability of ghrelin to interact with its receptors, would eventually lead to decreased appetite and thereby decrease body weight gain. To test our hypothesis, pigs were actively immunized against ghrelin. Ghrelin((1-10)) was conjugated to BSA and emulsified in Freund's incomplete adjuvant and diethylaminoethyl-dextran. Primary immunization was given at 19 weeks of age (WOA), with booster immunizations given 20 and 40 days after primary immunization. Body weight (BW) and plasma samples were collected weekly beginning at 19 WOA, and feed intake was measured daily. Fourteen days after primary immunization, the percentage of bound (125)I-ghrelin in plasma from immunized pigs was increased compared with control animals (P<0.001). Voluntary feed intake was decreased more than 15% in animals that were actively immunized against ghrelin compared with controls. By the end of the experiment, immunized pigs weighed 10% less than control animals (P<0.1). Concentrations of GH were increased (P<0.05) in immunized pigs. Apoptosis was not observed in post-mortem samples obtained from the fundic region of the stomach. Our observations suggest that immunization against ghrelin induces mild anorexia. This procedure could potentially be used as a treatment to control caloric intake and obesity.

Effects of intranasal administration of a leptin-secreting Lactococcus lactis recombinant on food intake, body weight, and immune response of mice

Leptin is an adipocyte-derived pleiotropic hormone that modulates a large number of physiological functions, including control of body weight and regulation of the immune system. In this work, we show that a recombinant strain of the food-grade lactic acid bacterium Lactococcus lactis (LL-lep) can produce and efficiently secrete human leptin. The secreted leptin is a fully biologically active hormone, as demonstrated by its capacity to stimulate a STAT3 reporter gene in HEK293 cells transfected with the Ob-Rb leptin receptor. The immunomodulatory activity of leptin-secreting L. lactis was evaluated in vivo by coexpression with the human papillomavirus type 16 E7 protein. In C57BL/6 mice immunized intranasally with a recombinant L. lactis strain coproducing leptin and E7 antigen, the adaptive immune response was significantly higher than in mice immunized with recombinant L. lactis producing only E7 antigen, demonstrating adjuvanticity of leptin. We then analyzed the effects of intranasally administered LL-lep in obese ob/ob mice. We observed that daily administration of LL-lep to these mice significantly reduced body weight gain and food intake. These results demonstrate that leptin can be produced and secreted in an active form by L. lactis and that leptin-producing L. lactis regulates in vivo antigen-specific immune responses, as well as body weight and food consumption.

Dietary repletion can replenish reduced T cell subset numbers and lymphoid organ weight in zinc-deficient and energy-restricted rats

The objective of the present study was to investigate the time course for recovery of lymphoid tissue and T cell subset numbers when Zn-deficient (ZD) or energy-restricted (ER) rats were repleted with control diet; in a second experiment, the link between the stress axis and lymphoid organs was explored. During the deficiency phase, rats were fed a ZD (<1 mg Zn/kg) or control diet (30 mg Zn/kg, nutritionally complete) either as pair-fed controls (ER) or ad libitum-fed controls (CTL) for 3 weeks. During the repletion phase, all rats were fed control diet ad libitum for 3, 7 or 23 d. After the deficiency phase, ZD and ER had lower T cell subset numbers in the thymus compared with CTL, and ZD had reduced T cell subset numbers in the spleen compared with both ER and CTL. T cell subset numbers and lymphoid organ weights recovered from dietary Zn deficiency and energy restriction by 7 d of repletion (except 23 d for thymus weight in ZD), while body weight required more than 23 d for recovery. At the end of the deficiency phase, ZD and ER had higher circulating corticosterone concentrations compared with CTL; plasma TNFα was not detectable and there were no differences in plasma haptoglobin, an acute-phase protein. In conclusion, Zn deficiency and energy restriction elevated circulating corticosterone and reduced T cell subset numbers in the thymus and spleen of growing rats. Repletion with a nutritionally complete diet allowed recovery of T cell subset numbers and lymphoid organ weight.

The effects of inulin supplementation of diets with or without hydrolysed protein sources on digestibility, faecal characteristics, haematology and immunoglobulins in dogs

Dogs with food allergy are often treated by giving a diet with hydrolysed protein sources. Prebiotics might also be successful in prevention and treatment of allergic disease through their effect on the colonic microflora, analogous to studies on probiotics in allergic children. The present study was set up to investigate the effect of supplementing inulin (IN) to commercial hypoallergenic dog diets on apparent nutrient digestibility, faecal characteristics, haematology and Ig in dogs. Supplementation of 3 % IN did not affect faecal pH, food and water intake and urine production. Compared with the intact protein diet with a limited number of ingredients (L), the diet with a hydrolysed protein source (H) resulted in an increased water intake (P<0·001), which could be due to the osmotic effect of free amino acids. Faeces production was increased by IN due to increased faecal moisture content. Increased faeces production on the H diet was mainly due to a higher DM excretion. Subsequently, the apparent digestibility coefficient (ADC) of DM was lower in the H diet group. A similar result was noted for ADC of diethyl ether extract and crude ash. The ADC of crude protein was higher in the H diet group, whereas IN decreased the ADC of crude protein. Differences in the ADC of crude protein among the different diets disappeared after correction for a higher faecal biomass, except for the dogs fed the L + IN diet. Total faecal IgA concentrations were lower in the H group (P<0·05) because of lower antigenic stimulation of hydrolysed protein, which implies that hydrolysed protein is really hypoallergenic. The present study indicates that the use of hydrolysed protein diets for canine food allergy treatment can affect digestibility and that combination with IN affected apparent protein digestibility but not IgA response.

Antibodies against the melanocortin-4 receptor act as inverse agonists in vitro and in vivo

Functionally active antibodies (Abs) against central G-protein-coupled receptors have not yet been reported. We selected the hypothalamic melanocortin-4 receptor (MC4-R) as a target because of its crucial role in the regulation of energy homeostasis. A 15 amino acid sequence of the N-terminal (NT) domain was used as an antigen. This peptide showed functional activity in surface plasmon resonance experiments and in studies on HEK-293 cells overexpressing the human MC4-R (hMC4-R). Rats immunized against the NT peptide produced specific antibodies, which were purified and characterized in vitro. In HEK-293 cells, rat anti-NT Abs showed specific immunofluorescence labeling of hMC4-R. They reduced the production of cAMP under basal conditions and after stimulation with a synthetic MC4-R agonist. Rats immunized against the NT peptide developed a phenotype consistent with MC4-R blockade, that is, increased food intake and body weight, increased liver and fat pad weight, and elevated plasma triglycerides. In a separate experiment in rats, an increase in food intake could be produced after injection of purified Abs into the third ventricle. Similar results were obtained in rats injected with anti-NT Abs raised in rabbits. Our data show for the first time that active immunization of rats against the NT sequence of the MC4-R results in specific Abs, which appear to stimulate food intake by acting as inverse agonists in the hypothalamus.

Maternal antibodies in a wild altricial bird: effects on offspring immunity, growth and survival

1. In many animals immunity is not fully developed until adulthood but the young still need protection against various sets of pathogens. Thus, bird nestlings are highly dependent on antibodies received from their mother (in the eggs) during their rapid early growth period. The relationship between maternal immunity and the development of neonates' own immunity has been poorly studied. 2. It has been suggested that immune function plays an important part in mediating resource competition between different life-history traits, e.g. growth and reproduction. Maternal investment of antibodies has potentially permanent effects on offspring phenotype. Thus, the trade-offs between the immune function and other important life-history traits in the offspring will also affect the fitness of the mother. 3. Our supplemental feeding experiment in the magpie Pica pica indicates that the immunoglobulin levels of offspring at hatching are dependent on a mother's nutritional condition. In addition, the amount of maternal immunoglobulins transferred to offspring increases along the laying order within a nest. 4. We also found that at the age of 8-10 days the immunoglobulin production of the offspring has already begun. Furthermore, the maternal immunoglobulin levels of the offspring at hatching were positively related to their immunoglobulin levels on day 10. 5. Maternal immunoglobulins did not significantly affect offspring growth, but there was a negative relationship between self-produced immunoglobulins and growth over the first 10 days, indicating a trade-off between these traits. Nestlings' weight, however, had a positive relationship with immunoglobulin production suggesting that the observed trade-off between growth and immunoglobulin production is due to catch-up growth of nestlings with a low hatching weight. We found that within nests nestlings with higher maternal antibody levels had higher survival rate until day 20, but between nests there was an opposite relationship. 6. Evidently, there is a trade-off, in magpies, between maternal resources, immune function and growth, shaping the evolution of maternal investment in offspring immunity.

Measurements of eosinophil activation before and after food challenges in adults with food hypersensitivity

BACKGROUND

Objective assessment of inflammatory reactions in the gastrointestinal tract could be useful in the diagnosis of food hypersensitivity. The aim of the present study was to investigate the involvement of eosinophils and mast cells in the inflammatory response of patients with food hypersensitivity before and after food challenges.

METHODS

Eleven patients (4 with IgE-mediated allergy and 7 without) with food hypersensitivity and positive double-blind, placebo-controlled food challenge were subjected to food challenge in a single-blinded fashion. Four subjects with no known food hypersensitivity were recruited as controls. Placebo was given after a 1-week washout period followed by an active dose. Stool, urinary and serum samples were collected and symptoms were recorded in a diary. Fecal samples were analyzed for eosinophil protein X (F-EPX) and tryptase; urinary samples for EPX (U-EPX) and leukotriene E4 (U-LTE4) and serum samples were analyzed for eotaxin and food-specific IgE antibodies.

RESULTS

Patients with IgE-mediated food allergy had increased levels of F-EPX compared to controls and tended to have lower serum levels of eotaxin compared to non-allergic patients and controls. U-LTE4 was significantly higher in allergic patients compared to non-allergic patients after challenge. Moreover, F-EPX correlated to U-LTE4 (p = 0.011). Reported symptoms, abdominal pain, distension, flatulence and nausea were similar in the allergic and non-allergic patients.

CONCLUSION

The results strongly indicate that eosinophils are activated in the gastrointestinal tract of food-allergic patients but not in patients with non-allergic food hypersensitivity. Due to the inconsistent pattern of symptoms after placebo and active food challenge, it was not possible to relate the levels of inflammation markers to the recorded symptoms.

Feeding, exploratory, anxiety- and depression-related behaviors are not altered in interleukin-6-deficient male mice

Interleukin-6 (IL-6) has been implicated in behavioral responses associated with inflammation, sickness behavior and various nervous system disorders. We studied a range of different behaviors in IL-6-knockout (IL-6ko) and wild-type (WT) male mice. No significant differences were observed in ambulatory, exploratory, and stereotypic activities in home or novel cages, in an open field (OF), in the multicompartment chamber (MCC), or in the elevated plus-maze (EPM). IL-6ko mice shed fewer fecal boli than WT mice in the OF, in novel cages and in the MCC although this effect was not statistically significant in the OF. In novel cages, intraperitoneal (i.p.) injection of IL-6 (1 microg) depressed ambulatory activity slightly more in IL-6ko than in WT mice. Restraint and interleukin-1beta (IL-1beta, 100 ng i.p.) decreased exploration of mice in the MCC and EPM, but there was no indication of altered sensitivity in IL-6ko mice. No significant differences were detected in the tail suspension and the Porsolt forced swim tests. IL-1beta and lipopolysaccharide (LPS 1 microg i.p.) injection depressed sweetened milk and solid food intake similarly in IL-6ko and WT mice, but IL-6 had no effect, suggesting that IL-6 is not involved in these effects of IL-1 or LPS. However, IL-1beta and LPS depressed body weight more in WT than in IL-6ko mice. Plasma corticosterone and basal concentrations of catecholamines, indoleamines and their metabolites in several brain regions were similar. The responses in these measures to IL-1beta and LPS were also similar, except that there were no significant changes in tryptophan and serotonin metabolism in IL-6ko mice. This may reflect a role for IL-6 in the tryptophan and serotonin responses to IL-1 and LPS. It is concluded that the lack of IL-6 is not associated with substantial alterations in several different mouse behaviors, and in the responses to restraint, IL-1beta, IL-6 and LPS.

Immune control of food intake: enteroendocrine cells are regulated by CD4+ T lymphocytes during small intestinal inflammation

BACKGROUND AND AIMS

Gastrointestinal inflammation reduces food intake but the biological mechanisms explaining suppressed feeding during inflammation are unknown. We have used a model of upper gut infection (Trichinella spiralis in the mouse) to study the effect of inflammation on food intake, and explored the role of a key enteroendocrine cell (EEC) in the regulation of feeding by the immune response.

METHODS

Food intake of NIH mice infected with the intestinal nematode Trichinella spiralis was measured. Duodenal cholecystokinin (CCK) cells were counted. Plasma CCK was measured. Infected mice were treated with a specific CCK1 receptor antagonist, and food intake reassessed. The influence of the immune response on food intake and CCK was mechanistically examined by treating mice with CD4 or mast cell neutralising antibodies. The role of the T helper 2 response was further explored in mice genetically deficient for interleukin (IL)-4, IL-13, or IL-4Ralpha (receptor alpha subunit).

RESULTS

Food intake of infected mice was significantly reduced at the temporal peak of intestinal inflammation. CCK expressing EEC were upregulated in infected mice, and plasma CCK levels were increased. A CCK1 receptor antagonist restored the food intake of infected mice to a significant degree. Furthermore, suppression of food intake was completely abolished in the absence of CD4+ T lymphocytes or IL-4Ralpha.

CONCLUSIONS

The data show for the first time that intestinal inflammation results in reduced food intake due to upregulation of CCK. Moreover, following infection, food intake and CCK expressing cells are under the specific control of CD4+ T-cells, via release of IL-4 and IL-13.

Interleukin-6 genetic ablation protects from trinitrobenzene sulfonic acid-induced colitis in mice. Putative effect of antiinflammatory cytokines

BACKGROUND

Interleukin (IL)-6 is a proinflammatory cytokine implicated in the pathogenesis of inflammatory bowel disease. IL-6 is locally upregulated in inflammatory bowel disease patients and in murine models of experimental colitis. Treatment with anti-IL-6 receptor antibody ameliorates intestinal inflammation.

OBJECTIVE

It was the aim of this study to investigate the role of genetic IL-6 deficiency in trinitrobenzene sulfonic acid (TNBS)-mediated colitis, an experimental model inflammation that shares several features with Crohn's disease in humans.

METHODS

Acute colitis was induced in wild-type and IL-6-deficient (Il-6(-/-)) mice by intracolonic administration of TNBS. Forty-eight hours after treatment, the local and systemic features of inflammation, i.e. food intake, weight loss, histological markers of colitis, cytokine expression by real-time PCR, food intake and body weight changes, were assessed.

RESULTS

In wild-type mice, TNBS administration increased both IL-6 serum levels and local expression of IL-6 by 36 and 9 fold, respectively, compared with control, vehicle-injected mice. Compared with the wild-type mice, the Il-6(-/-) mice had significantly reduced intestinal inflammation as evidenced by epithelial damage, neutrophil infiltration, colon thickness and proinflammatory cytokine expression, following treatment with TNBS. Moreover, baseline levels of the antiinflammatory cytokines IL-10 and tumor growth factor-beta were significantly elevated in Il-6(-/-)compared with the wild-type mice.

CONCLUSIONS

Our results demonstrate that Il-6(-/-)are partially protected from the development of TNBS-induced acute experimental colitis, most likely via their significantly elevated baseline levels of antiinflammatory cytokines.

Glutamine supplementation influences immune development in the newly weaned piglet

A study was conducted to determine changes that occur in immune function during the early post-weaning period and the effect of supplementing glutamine (gln, 4% w/w) to the weaning diet of piglets. Dutch-Landrace piglets (n=10/group) were killed prior to weaning (21 d) or randomized to one of two nutritionally complete weaning diets with or without gln. With age there was an increased ability of peripheral blood mononuclear cells (PBMC) and mesenteric lymph nodes (MLN) cells to proliferate (rate of (3)H-thymidine uptake) to T cell mitogens (P<0.05). PBMC from older piglets produced less of a Th-1 type response after stimulation (P<0.05). Adding gln to the weaning diet significantly (P<0.05) modified immune cells in the MLN, in a potentially beneficial manner (with respect to mucosal infections) by preventing an increase in antigen naïve CD4+ cells, increasing the proliferative response to pokeweed mitogen and supporting a Th-1 type cytokine response after T cell (phytohemagglutinin) stimulation.

Implementation of the EGFP-K562 flow cytometric NK test: Determination of NK cytotoxic activity in healthy elderly volunteers before and after feeding

BACKGROUND

Natural Killer (NK) cells are key actors of innate immunity that supervise the organism's cells, and fight against viral infections and cancer development through their cytotoxic activity. This cytotoxic activity is modulated by cytokines and hormones and could be influenced by physiological or pathological conditions. New techniques for measuring NK cytotoxic activity by flow-cytometry have recently been developed, and they correlated strongly with the standard chromium ((51)Cr) release assay. Our aim was to implement a previously published enhanced green fluorescent protein (EGFP)-K562 flow cytometric method and use it to evaluate NK cytotoxic activity under different nutritional conditions.

METHODS

NK effector cells were isolated from peripheral blood mononuclear cells, and a K562 cell line stably transfected by EGFP was used as target cells. Different analytical parameters, including cell ratios and incubation times, were studied to improve the EGFP-K562 flow cytometric NK test conditions.

RESULTS

The optimized test was then used to determine the effect of fasting and refeeding on NK cell numbers and activity in a physiological situation. NK cytotoxic activity in fasted conditions (30.4 +/- 4.4%) increased by a factor 1.7 +/- 0.2 (P = 0.0025) in nourished conditions (45.0 +/- 4.6%) in healthy elderly people.

CONCLUSION

Therefore, this method provides a reliable, reproducible and rapid test for analyzing NK cytotoxicity under various conditions.

The effects of lipopolysaccharide and lithium chloride on the ingestion of a bitter-sweet taste: comparing intake and palatability

Activation of the immune system with lipopolysaccharide (LPS) has been shown to result in decreased consumption of normally preferred substances while at the same time not affecting palatability. The present study examined the effects LPS administration on both intake and palatability of a relatively unpalatable bitter-sweet taste. Bitter is thought to signal a danger cue to an animal representing a potential toxin-containing food. Using a one-bottle consumption test, voluntary intake of a sucrose-quinine (0.15 M sucrose + 0.00015 M quinine; S-Q) solution was assessed in rats on two conditioning days (days 1 and 4) after a systemic injection with LPS, LiCl, or NaCl. On the test day (day 7), rats were given 1h access to the same solution in the absence of any injection. In a separate experiment, rats fitted with intraoral cannulae received similar testing schedules, however, the solution was delivered intraorally, activating only the consummatory responses of the animal. During conditioning, rats received 5 brief (1 min) intraoral infusions of the taste across a 1h period following injections of LPS, LiCl or NaCl. Individual taste reactivity responses were recorded and analyzed. Both LPS and LiCl resulted in decreased consumption of the unpalatable taste relative to controls on the test day, suggesting typical conditioned taste avoidance. When the consummatory responses were examined, LPS-treatment produced an increase in active oral rejection relative to NaCl- and LiCl-treated groups on both conditioning days. The present study demonstrates that although both LPS- and LiCl-treatment result in similar conditioned avoidance using an intake measure, they do not elicit similar patterns of taste reactivity responding to intraoral infusions of the bitter-sweet taste. Furthermore, the present results suggest that immune activation with LPS-treatment results in increased rejection of a mildly aversive stimulus and supports the hypothesis that reorganization of behavioral priorities occurs during bacteria-induced sickness.

The role of central corticotropin-releasing hormone in the anorexic and endocrine effects of the bacterial T cell superantigen, Staphylococcal enterotoxin A

Bacterial superantigens, such as the staphylococcal enterotoxins, exert a strong capacity for in vivo stimulation of T cell proliferation and cytokine production. Previously, staphylococcal enterotoxin A (SEA) was shown to induce an anorexic effect under novel contextual conditions of testing, and produced an increase in plasma ACTH and corticosterone levels in C57BL/6J mice. In the present study, the role of corticotropin releasing hormone (CRH) in promoting these effects of SEA was addressed via intracerebroventricular (icv) administration of alpha-helical CRH(9-41) ((alpha)hCRH), a non-selective CRH receptor antagonist, and astressin-2B, a selective CRH receptor 2 antagonist. The efficacy of (alpha)hCRH and astressin-2B in blocking anorexic responses to CRH and urocortin under the current conditions of testing was first confirmed. Subsequently, it was found that (alpha)hCRH (20 microg icv), but not astressin-2B (10 and 25 microg icv), significantly attenuated the anorexia induced by SEA. This suggested that central CRH is involved in mediating the anorexia induced by SEA, but potentially through CRH receptor 1. Additional results revealed that plasma ACTH stimulation in response to SEA was not significantly attenuated by either antagonist administered icv. However, the plasma corticosterone elevation showed a modest, but significant, attenuation in SEA challenged mice given (alpha)hCRH. These data suggest a possible influence of central CRH on adrenocorticoid activity subsequent to SEA challenge. More importantly, it appears that central activation of CRH receptors is a consequence of SEA challenge, and this likely contributes to its anorexic effects.

Chronic restraint stress during early Theiler's virus infection exacerbates the subsequent demyelinating disease in SJL mice

Chronic restraint stress, administered during early infection with Theiler's virus, was found to exacerbate the acute central nervous system (CNS) viral infection and the subsequent demyelinating phase of disease (an animal model of Multiple Sclerosis (MS)) in SJL male and female mice. During early infection, stressed mice displayed decreased body weights and spontaneous activity; while increased behavioral signs of illness and plasma corticosterone (CORT) levels. During the subsequent chronic demyelinating phase of disease, previously stressed mice had greater behavioral signs of the chronic phase, worsened rotarod performance, and increased inflammatory lesions of the spinal cord. In addition, mice developed autoantibodies to myelin basic protein (MBP), proteolipid protein peptide (PLP139-151), and myelin oligodendrocyte glycoprotein peptide (MOG33-55).

Behavioral effects of infection with interferon-gamma adenovector

Anxiety and depression of unknown etiology are frequent complications of the systemic autoimmune disease lupus erythematosus (SLE). To elucidate key pathogenic factors we study the "autoimmunity-associated behavioral syndrome" (AABS) in lupus-prone MRL-lpr mice. Based on the evidence that serum levels of the neuroactive cytokine interferon-gamma (IFN-gamma) are increased both in human and murine forms of SLE, the present study examines whether sustained IFN-gamma production in non-autoimmune mice induces deficits comparable to AABS, particularly in tasks reflective of emotional reactivity and motivated behavior. For this purpose, wild-type and IFN-gamma knockout C57BL/6J mice were infected with adenovirus carrying the cDNA for murine IFN-gamma (i.p. 2 x 10(8) pfu of virus per mouse) and shortly thereafter tested in the behavioral battery used in the detection of AABS. Serum levels of IFN-gamma were found to peak 24 h after the infection, normalized within 5 days. Although all infected animals showed reduced food/water intake and body weight, the recovery rate was slower in groups injected with IFN-gamma virus. No deficits were observed in the models of anxiety, but blunted responsiveness in the sucrose preference test (a putative model of anhedonia) lasted well beyond the IFN-gamma clearance period. These results suggest that a relatively brief elevation in systemic IFN-gamma levels impairs ingestive behavior and leads to prolonged changes in motivated behavior. As such, they are consistent with the hypothesis that upregulation in synthesis of pro-inflammatory cytokines contributes to induction of AABS and more specifically, to limbic system dysfunction during lupus-like disease.

Physiology of immunity in the water flea Daphnia magna: environmental and genetic aspects of phenoloxidase activity

In an attempt to understand the ecological correlates of immunocompetence in Daphnia magna (Crustacea, Cladocera), we tested for variation in immune function in relation to feeding conditions, host conditions, and host genotype. We investigated both phenotypic (environmental dependent and condition dependent) as well as genotypic aspects of the prophenoloxidase activating system (Pro-POAS), which has been described as a key factor in invertebrate immunity. Daphnia magna is an ideal study system to disentangle phenotypic and genetic variation because females can reproduce clonally. Well-fed Daphnia showed higher phenoloxidase (PO) activity than Daphnia kept at a low food level. Wounding provoked a higher level of PO activity, indicating that the Pro-POAS was condition dependent. Further, we found clonal variation in PO activity among four clones of D. magna isolated from four different populations. The same four clones were tested for their resistance to the bacterial pathogen Pasteuria ramosa. High resistance corresponded to high PO activity. Our results suggest adaptive variation in PO activity and suggest that its expression is costly. These costs may influence the evolution of the PO activity level and the maintenance of its genotypic variation.

A potent human C5a receptor antagonist protects against disease pathology in a rat model of inflammatory bowel disease

The complement system is implicated in the pathogenesis of human inflammatory bowel disease, but the specific role of C5a has never been examined. We have compared the efficacy of an orally active human C5a receptor antagonist (AcPhe[Orn-Pro-D-cyclohexylalanine-Trp-Arg]), prednisolone, and infliximab against trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats. The drugs were administered either 2 days before or 24 h after TNBS instillation, and rats were then examined after 8 days. Drug-free colitis control rats showed severe disease pathology with significant mortality (39%). Rats pre or posttreated with the C5a antagonist (10 mg/kg/day peroral, 0.3 mg/kg/day s.c.) had reduced mortality and significantly improved macroscopic scores, colon edema, colon myeloperoxidase levels, reduced concentrations of TNF-alpha levels in the colon and serum, and had greater food intake resulting in greater weight gains than colitis-only rats. Rats pretreated with prednisolone (1 mg/kg/day s.c.) displayed significant improvement in parameters measured, but posttreatment was ineffective. Single dose pretreatment with the TNF-alpha inhibitor infliximab (3 mg/kg i.v.) also had significant improvements in the parameters measured. Rats pretreated with a combination of the C5a antagonist and prednisolone showed no greater improvements than either drug alone. These findings suggest a central role for complement, particularly C5a, in the pathology of TNBS-induced colitis in rats, indicating a possible therapeutic role for C5a antagonists in inflammatory bowel disease.

Breakdown of immunity to Nippostrongylus brasiliensis in lactating rats

The nutritional basis of breakdown of immunity to parasites may be addressed in a rodent model. We hypothesized that lactating rats would show a breakdown of immunity to Nippostrongylus brasiliensis, and that this breakdown of immunity would be sensitive to protein supply. Rats were immunized with 1600 infective N. brasiliensis larvae and subsequently mated. During lactation, these rats were offered foods with 90 (low protein; LP) or 210 (high protein, HP) g crude protein (Nx6.25)/kg and re-infected with 400, 800 or 1600 larvae on day 2 post-parturition. Immunized non-reproducing rats were offered a food containing 60 g crude protein/kg and re-infected with 1600 larvae. Seven days after secondary infection, lactating rats had more adult nematodes in their small intestine and nematode eggs in their colon contents than the non-reproducing rats. Protein supply did not affect worm or egg counts, although LP rats carried relatively more female nematodes than the HP rats. All lactating rats had lower intakes than expected from previous studies using similar nutritional protocols. This may have resulted in insufficient protein supply, even for the HP rats, and this could explain the absence of effects of protein supply on egg and worm counts. We conclude that a breakdown of immunity to N. brasiliensis can occur in lactating rats; this strongly suggests that the lactating rat is a suitable model for elucidating a possible nutritional basis of breakdown of immunity to parasites. However, sufficient protein intake must be achieved to address the hypothesis that breakdown of immunity to N. brasiliensis is sensitive to protein supply.

Activation of the immune system in rats with lipopolysaccharide reduces voluntary sucrose intake but not intraoral intake

Traditional intake measures of voluntary consumption of food or fluid from a specific location involve both appetitive and consummatory behaviors. Appetitive behaviors are food finding behaviors displayed by an animal prior to the consumption of the food, whereas consummatory behaviors are the behaviors involved in the actual consumption of the food. Intraoral intake of a fluid can be measured by directly infusing it into the oral cavity of an animal and quantifying the consummatory behaviors. The present study compared the effects of immune activation (lipopolysaccharide, LPS) and toxin (lithium chloride, LiCl)-induced changes on both a traditional intake measure (bottle drinking) and an intraoral intake measure. In Experiment 1, rats were injected intraperitoneally with LPS (200 microg/kg), LiCl (0.15 M, 20 ml/kg) or NaCl vehicle, and voluntary sucrose (0.3 M) intake was monitored for 1 h from a graduated drinking tube. Voluntary intake was again assessed on a second test day, 72 h later under the same conditions. In Experiment 2, a continuous intraoral infusion of sucrose (0.3 M) was given via intraoral cannulae following systemic injections of LPS, LiCl or NaCl vehicle on two different test days, 72 h apart. Rats injected with LiCl displayed reduced sucrose intake on both the voluntary intake measure and the intraoral intake measure relative to controls (P's<.05). The reduced intake observed was of greater magnitude on the second test day of both experiments, consistent with conditioning effects. In contrast, LPS reduced sucrose intake only when assessed with the traditional intake measure. Intraoral sucrose intake remained unchanged relative to controls. The present results provide further evidence that activation of the immune system has adverse effects on the appetitive phase of ingestion, whereas the consummatory aspects are unaffected.

The role of proinflammatory cytokines in wasting disease during lymphocytic choriomeningitis virus infection

Infection with pathogens often leads to loss of body weight, but the cause of weight loss during infection is poorly understood. We used the infection of mice with lymphocytic choriomeningitis virus (LCMV) as a model to study how pathogens induce weight loss. If LCMV is introduced into the CNS of CTL-deficient mice, the immune response against the virus leads to a severe weight loss called wasting disease. We planned to determine what components of this antiviral immune response mediate wasting disease. By adoptive transfer, we show that CD4 T cells activated by LCMV infection are sufficient to cause wasting disease. We examined the role of cytokines in LCMV-induced wasting disease using mice lacking specific cytokines or cytokine receptors. Results of adoptive transfer experiments suggest that TNF-alpha is not involved in LCMV-induced wasting disease and show that IFN-gamma contributes to the disease. Consistent with a role for IFN-gamma in wasting, we find that IFN-gamma is necessary for LCMV-specific CD4 T cell responses in the CNS, most likely because it is required to induce MHC class II expression. Our data also indicate that IL-1 is required for LCMV-induced wasting and that IL-6 contributes to the wasting disease. Additionally, our results identify alpha-melanocyte-stimulating hormone as a potential mediator of the disease. Overall, this work defines the critical role of virus-primed CD4 T cells and of proinflammatory cytokines in the pathogenesis of wasting disease induced by LCMV infection.

Anorexia in a rat model of colitis: interaction of interleukin-1 and hypothalamic serotonin

BACKGROUND AND AIMS

Anorexia induced by experimental colitis in rats is mediated, in part, by increased release of serotonin (5-HT) from the hypothalamic paraventricular nucleus (PVN). In this model, anorexia is attenuated by treatment with an interleukin-1 (IL)-1 receptor antagonist (ra). However, a functional link between central IL-1 receptors and 5-HT release remains unproven. We have tested the hypothesis that anorexia associated with experimental colitis is mediated by IL-1 induced release of 5-HT.

METHODS

In vivo 5-HT release in the PVN was measured in rats with 2,4,6-trinitrobenzenesulphonic acid (TNBS)-induced colitis, treated with intracerebroventricular infusion of IL-1ra or vehicle treated controls. The effect of inhibition of tumour necrosis factor-alpha on food intake and PVN 5-HT release in TNBS-colitis was also tested.

RESULTS

In rats with TNBS-induced colitis, intracerebroventricular infusion of IL-1ra resulted in a 18-fold reduction in PVN 5-HT release compared to vehicle-treated controls. This was associated with a significant increase in food intake in IL-1ra treated rats. In contrast intracerebroventricular administration of anti-tumour necrosis factor antibodies had no effect on either PVN 5-HT release or food intake in rats with TNBS-induced colitis.

CONCLUSIONS

In animals with TNBS-colitis, anorexia is mediated, in part, by the stimulatory effect of IL-1 on medial hypothalamic 5-HT.

Malnutrition-induced macrophage apoptosis

BACKGROUND

Human and murine studies suggest protein-calorie malnutrition (PCM) results in significant host immunosuppression resulting in increased morbidity and mortality. Apoptosis has been implicated as an important mediator in the immunosuppression observed in several disease states. This study was designed to characterize macrophage apoptosis in a murine model of PCM and investigate components that regulate the apoptotic process, such as protein kinase C (PKC) and Bcl-2 activity.

METHODS

Swiss-Webster mice (n = 50) were randomly assigned to receive either a control (24% protein) or a PCM diet (0% protein) for 7 days. Peritoneal macrophages were harvested and detection of apoptosis was performed by terminal deoxy-transferase-mediated deoxyuridine triphosphate (dUTP) nick-end labeling (TUNEL) and propidium iodide DNA staining under baseline and pro-apoptotic conditions. Pro-apoptotic conditions included cells treated with tumor necrosis factor-alpha (TNF-alpha) (10 ng/mL), interferon-gamma (IFN-gamma) (10 ng/mL), and a combination of both agents. In addition, levels of PKC activity and expression of Bcl-2 and p53 protein were measured.

RESULTS

Peritoneal macrophages from PCM mice had a significantly greater amount of apoptosis at baseline and under stimulated conditions compared with controls. Levels of PCM apoptosis were elevated at baseline by TUNEL staining compared with macrophages from the control group (16.5% +/- 1.4%, versus 4.5% +/- 1.1%, P <.01). In addition, peritoneal macrophages from the malnourished animals were significantly more susceptible to the apoptotic effect of TNF-alpha and the effects of INF-gamma (27.3% +/- 2.1% and 31% +/- 1.4%) compared with control mice (5.5% +/- 0.7% and 7.2% +/- 0.5%, P <.01), respectively. Again, an increase in the baseline apoptosis rate was demonstrated in peritoneal macrophages from PCM mice compared with control fed mice (13.2% +/- 4.4% versus 4.3% +/- 3.1%, P <.01) as measured by propidium iodide staining. The combination of agents, TNF-alpha and INF-gamma, resulted in an additive apoptotic effect in the malnourished host compared with the control animals (43.4% +/- 4.7% versus 10.5% +/- 2.2%, P <.01), respectively. Furthermore, there was a significant decrease in the mean total PKC activity in the malnourished macrophages compared with results in controls (110,000 +/- 8000 versus 60,000 +/- 4000 cpm, P <.01). Similar changes were also observed in PKC cytosolic and membrane activity between both groups. In addition, Bcl-2 protein expression was significantly decreased in PCM animals compared with control animals.

CONCLUSIONS

Thus, peritoneal macrophages from PCM mice exhibit significantly greater levels of apoptosis at baseline and when stimulated with pro-apoptotic agents compared with controls. The propensity of macrophages from PCM mice to undergo apoptosis may be attributable in part to decreased PKC activity and Bcl-2 protein expression. These findings may help to explain the associated immune dysfunction observed in malnutrition.

The reductions in sweetened milk intake induced by interleukin-1 and endotoxin are not prevented by chronic antidepressant treatment

Administration of interleukin-1 (IL-1) and endotoxin (lipopolysaccharide, LPS) to rodents can decrease food intake, a behavioral response resembling the diminution of appetite observed in human depression. IL-1 and LPS are known to affect cerebral neurotransmission involving norepinephrine and serotonin, both of which have been implicated in feeding behavior and in the pharmacotherapy of depression in man. The ability of chronic antidepressant treatment to attenuate LPS-induced depressed feeding in rats has been cited as evidence that cytokines may be involved in human depression. Thus, we studied the effects of chronic treatment with the tricyclic antidepressant, imipramine, and the novel antidepressant, venlafaxine, on the sweetened milk intake challenged with intraperitoneally injected IL-1 beta and LPS. Chronic (from 2 to 8 weeks) treatment of the mice with imipramine (10 mg/kg once or twice daily) or venlafaxine (10 and 20 mg/kg/day) did not significantly alter the decreases in milk intake in response to mIL-1 beta or LPS. In some experiments, chronic imipramine slightly decreased body weight and slightly increased milk intake, but not food pellet intake. Venlafaxine had none of these effects. Analysis of variance did not indicate any significant interactions between the antidepressant and IL-1 or LPS treatments. These results indicate that chronic treatment with antidepressants does not significantly alter the responses to IL-1 or LPS in the mouse sweetened milk model of sickness behavior.