concanavalin-a and Weight-Loss

Few chronic food protein models have described the relationship between allergenicity and the molecular structure of food protein after physical processing. The effect of γ-radiation on the structure of food protein was measured by fluorescence, circular dichroism and microcalorimetry. BALB/c mice were intraperitoneally sensitized and then given non-irradiated and irradiated Con-A by daily gavage for 28days. The tendency to form insoluble amorphous aggregates and partially unfolded species was observed after irradiation. The administration of non-irradiated and irradiated samples at low-dose significantly increased weight loss as well as plasma levels of eotaxin in animals repeatedly exposed to Con-A. Significant lymphocytic infiltrate filling completely the stroma of microvilli and tubular glands was observed in the small intestinal of the group given Con-A irradiated at a low dose. This phenotype was not observed in animals treated with Con-A irradiated at a high dose.

Topics: Administration, Oral; Animals; Calorimetry, Differential Scanning; Circular Dichroism; Concanavalin A; Disease Models, Animal; Dose-Response Relationship, Radiation; Female; Food Hypersensitivity; Gamma Rays; Intestine, Small; Lymphocytes; Mice; Mice, Inbred BALB C; Microvilli; Protein Conformation; Weight Loss

Previously, we showed that mice fed white button mushrooms (WBM) had enhanced immune functions known to help the body's antiviral defence. In the present study, we tested whether WBM conferred protection against viral infection. Young (4-month-old) and old (22-month-old) C57BL/6 mice were fed a diet containing 0, 2 or 10 % WBM powder for 8 weeks. Mice were then infected with influenza Puerto Rico/8/34 (H1N1), and killed at day 0 (uninfected), 2, 5 or 7 post-infection. The primary outcomes of the study were viral titre and body weight. Secondary outcomes were natural killer (NK) cell activity, lymphocyte proliferation and cytokine production. The results showed that WBM did not affect viral titre, nor did it prevent infection-induced weight loss. WBM supplementation was found to enhance NK cell activity in old mice and to increase interferon (IFN)-γ production in young and old mice under naive (uninfected) conditions, but it had no such effect after infection. The lack of a mushroom supplementation effect on NK activity and concanavalin A-stimulated IFN-γ production after infection may explain the immune system's failure to reduce viral load and weight loss in mice after influenza infection. WBM supplementation, however, did induce changes in other aspects of the immune response: it significantly increased the production of T-helper type 2 cytokines IL-4 and IL-10 in uninfected mice and pro-inflammatory cytokines IL-1β and TNF-α in infected mice. These mushroom-induced systemic changes, however, were not adequate to confer a protective effect against influenza infection.

Topics: Agaricales; Animals; Concanavalin A; Diet; Disease Resistance; Food, Preserved; Influenza A Virus, H1N1 Subtype; Interferons; Killer Cells, Natural; Lung; Lymphocyte Activation; Mice; Mice, Inbred C57BL; Orthomyxoviridae Infections; Viral Load; Weight Loss

Epstein-Barr virus (EBV) is the causative agent of infectious mononucleosis (IM). In addition, latent infections with EBV are associated with nasopharyngeal carcinoma (NPC) and Burkitt's Lymphoma (BL). Antibodies to several EBV-encoded early antigens (EA) are often observed in patients with NPC and BL, however, the role of EBV-encoded proteins in the etiology of these and other EBV-associated diseases is not completely understood. The EA complex encodes for at least six different viral enzymes including deoxyuridine triphosphate nucleotidohydrolase (dUTPase). dUTPase has recently been shown to modulate activation of human peripheral blood mononuclear cells in vitro (unpublished data). Therefore, these studies were designed to test whether dUTPase would modulate immune function in an in vivo model. Mice were injected with purified EBV dUTPase, and baseline immune function and sickness behaviors were measured. EBV dUTPase treatment inhibited replication of mitogen-stimulated lymphocytes obtained from treated mice. These lymphocytes were also less able to synthesize interferon-gamma after re-stimulation. In addition, treatment with dUTPase induced sickness behaviors. For example, as compared to control animals, dUTPase-treated animals lost body mass, had elevated body temperature, and displayed diminished locomotor activity. These data suggest that individual viral proteins may play a role in the pathophysiology of EBV associated disease.

Topics: Animals; Concanavalin A; Eating; Epstein-Barr Virus Infections; Herpesvirus 4, Human; In Vitro Techniques; Interferon-gamma; Lipopolysaccharides; Lymphocyte Activation; Lymphocytes; Male; Mice; Motor Activity; Pyrophosphatases; Weight Loss

Treatment of mice with concanavalin A (Con A) (12.5 mg/kg, i.v.) decreased the body weight at 24 h. This Con A-induced body weight decrease was accompanied by reduction in food and water intake. Zaltoprofen is a non-steroidal anti-inflammatory drug. The administration of Zaltoprofen (10 mg/kg) at 8 h after Con A treatment was found to inhibit the Con A-induced reduction in body weight. The food intake in mice treated with Con A plus Zaltoprofen (10 mg/kg) was four times greater than that in mice treated with only Con A. The present results showed inhibition of the Con A-induced body weight loss by Zaltoprofen and suggested its possible effectiveness for the treatment of "sickness behavior".

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Benzopyrans; Body Weight; Concanavalin A; Dose-Response Relationship, Drug; Drinking; Eating; Female; Mice; Mice, Inbred BALB C; Propionates; Weight Loss

The effect of electrolytic lesion of the median raphe nucleus was measured on behavioral and physiological parameters related to stress 24 h after the lesion. In of the elevated plus-maze the lesion decreased the percentage of open arm entries and tended to shorten the time spent on the open arms indicating an increase in anxiety. In contrast, the lesion markedly increased the time spent in the bright (aversive) compartment of the light-dark box and decrease in attempts to cross from the dark toward the bright compartment, an anxiolyic effect. With the exception of plasma prolactin level, which was lowered by the lesion, the physiological measures used in the present study indicate that the lesioned animals are under stress. Thus, death rate and weight loss after the surgery were higher in lesioned than in control animals. In addition, lesioned animals showed higher plasma corticosterone levels, a high incidence of gastric ulcers in the fundus and a depressed immune response to the mitogen concavaline A. These results highlight the importance of the median raphe nucleus in the regulation of stress and anxiety. They also show that behavioral and physiological measures of stress may be dissociated.

Topics: Adrenal Cortex Hormones; Animals; Anxiety; Behavior, Animal; Concanavalin A; Male; Prolactin; Raphe Nuclei; Rats; Rats, Wistar; Stomach Ulcer; Stress, Physiological; Weight Loss

The mechanisms underlying inflammatory bowel disease (IBD) remain obscure but the importance of inflammatory processes is clear and most pharmacological therapies inhibit inflammation. The search for more effective agents with low toxicity continues. To test the possibility that the antiinflammatory/anticytokine peptide alpha-MSH can be used to control IBD, the peptide was administered to a murine colitis model. The peptide treatment had marked salutary effects: it reduced the appearance of fecal blood by over 80%, inhibited weight loss, and prevented disintegration of the general condition of the animals. Mice given alpha-MSH showed markedly lower production of TNF alpha by tissues of the lower colon stimulated with concanavalin A; the inhibitory effect of alpha-MSH on production of inflammatory nitric oxide by lower bowel tissue was even greater. The combined results indicate that alpha-MSH modulates experimental IBD, perhaps by inhibiting production within the gut of the local proinflammatory agents TNF alpha and nitric oxide, or by inhibiting inflammatory processes closely linked to these mediators.

Topics: alpha-MSH; Animals; Concanavalin A; Dextran Sulfate; Disease Models, Animal; Gastrointestinal Hemorrhage; Inflammatory Bowel Diseases; Intestine, Large; Male; Mice; Mice, Inbred BALB C; Nitric Oxide; Occult Blood; Tumor Necrosis Factor-alpha; Weight Loss

Although obese people have been reported to have a higher incidence of infections and some types of cancer, the immunocompetence of obese subjects remains poorly understood. To investigate whether obesity affects immunity, we studied obese subjects (BMI > 30 kg/m2) whose health was uncomplicated by any other disorder, including hyperglycemia. We compared mitogen-induced blastogenic response of peripheral blood lymphocytes in 34 obese subjects (mean +/- s.e. BMI: 38.4 +/- 2.0 kg/m2) and 35 non-obese controls (BMI: 21.3 +/- 0.4 kg/m2) who were matched for age and sex. The effects of weight reduction were also evaluated in 19 obese persons (BMI: 36.4 +/- 1.8 kg/m2) on a very low calorie diet. Mean (+/- s.e.) intracellular incorporation of [3H]-thymidine, on stimulation of T lymphocytes with either phytohaemagglutinin (PHA) or concanavalin A (Con A), and B lymphocytes with pokeweed mitogen, was significantly diminished in obese subjects compared to non-obese controls (47552 +/- 6917 vs. 83720 +/- 6252 cpm, P < 0.001; 30301 +/- 6018 vs. 45942 +/- 3723 cpm, P < 0.05; 13669 +/- 2971 vs. 23735 +/- 2048 cpm, P < 0.01, respectively). After weight reduction (BMI: 27.8 +/- 1.2 kg/m2), the mean T lymphocyte responses to PHA and Con A were increased significantly vs. baseline (98404 +/- 2444 vs. 50337 +/- 9516 cpm, P < 0.05 and 69523 +/- 15480 vs. 36695 +/- 8006 cpm, P < 0.05, respectively). Depressed blastogenesis of B lymphocytes was also augmented but was not statistically significant. The results suggest that obese subjects have underlying immune impairment in responsiveness of lymphocytes and that these impairments are reversible with adequate weight reduction.

Topics: Adult; Blood Glucose; Body Mass Index; Concanavalin A; Diet, Reducing; DNA; Female; Humans; Insulin; Lymphocyte Activation; Lymphocytes; Male; Middle Aged; Obesity; Phytohemagglutinins; Pokeweed Mitogens; Regression Analysis; Weight Loss

Wistar rats were submitted to the action of active lectins from common dry beans (Phaseolus vulgaris) and from jack beans (Canavalia ensiformis, DC). Raw common bean was offered to the rats in an otherwise balanced diet to make 10% protein as the sole protein source. A single dose of 20 mg of jack bean lectin (concanavalin A) was given by gastric intubation. Half of the rats receiving raw bean died within 22 days of experiment. Histological findings showed ulceration and necrosis of the intestinal villi in the surviving rats. In some cases the lesions reached also the submucosa. Gastric intubation of concanavalin A caused intense scaling off in the apical portion of the villi.

Topics: Animals; Concanavalin A; Diet; Duodenum; Fabaceae; Intestinal Mucosa; Intubation, Gastrointestinal; Lectins; Male; Phytohemagglutinins; Plant Lectins; Plants, Medicinal; Rats; Rats, Inbred Strains; Weight Loss