Comparison of microbiological and fermentation parameters obtained with an improved rumen in vitro technique with those obtained in vivo

The aim of the present work was to develop and evaluate a rapid in vitro technique to study the activity of rumen micro-organisms and to estimate the nutritive value of feeds. The rumen culture apparatus described here is essentially a batch system, modified in order to obtain conditions of strict anaerobiosis and the balanced growth of all the microbial forms present in the mixed rumen inoculum. Validation of this technique was carried out by comparing studies run simultaneously in vivo and in vitro, analysing microbial flora composition, biochemical parameters of rumen fluid and feed degradability. At the different incubation periods studied, degradability and biochemical parameters had very similar trends in the two systems and the microbiological analysis did not show any significant (P>0.05) differences between the in vivo and the in vitro approaches. The in vitro system described showed the possibility to maintain, for the time studied, a balanced microbial composition, which represents the equilibrium found in the animals. (C) 1998 Elsevier Science B.V

Immunogenicity of a Recombinant Influenza Virus Bearing Both the CD4+ and CD8+ T Cell Epitopes of Ovalbumin

Recombinant influenza viruses that bear the single immunodominant CD8+ T cell epitope OVA257−264 or the CD4+ T cell epitope OVA323−339 of the model antigen ovalbumin (OVA) have been useful tools in immunology. Here, we generated a recombinant influenza virus, WSN-OVAI/II, that bears both OVA-specific CD8+ and CD4+ epitopes on its hemagglutinin molecule. Live and heat-inactivated WSN-OVAI/II viruses were efficiently presented by dendritic cells in vitro to OT-I TCR transgenic CD8+ T cells and OT-II TCR transgenic CD4+ T cells. In vivo, WSN-OVAI/II virus was attenuated in virulence, highly immunogenic, and protected mice from B16-OVA tumor challenge in a prophylactic model of vaccination. Thus, WSN-OVAI/II virus represents an additional tool, along with OVA TCR transgenic mice, for further studies on T cell responses and may be of value in vaccine design

Homocystein plasma levels are independently associated with insulin resistance in normal weight, overweight and obese pre-menopausal women.

OBJECTIVES: The aim of the present study was to examine the relationship of homocysteine (Hcy) plasma levels to insulin resistance (IR). DESIGN: A cross-sectional study in a primary care setting. SUBJECTS AND METHODS: Fasting Hcy levels were measured in the plasma of 44 pre-menopausal women [17 normal weight (body mass index BMI 20.0-24.9 kg/m2), 7 overweight (BMI 25.0-29.9 kg/m2), 20 obese (BMI> or =30.0 kg/m2)], aged 18-45 yr. Other measurements included: central fat accumulation, as evaluated by waist circumference; IR, as calculated by homeostatic model assessment (HOMAIR); systolic and diastolic blood pressure; and fasting concentrations of glucose, insulin and lipids (total cholesterol, HDL-cholesterol, triglycerides). RESULTS: Hcy was positively correlated with insulin concentrations (p<0.01), HOMAIR (p<0.01), and systolic and diastolic blood pressure (p<0.01 and p<0.05, respectively). After multivariate analysis, only HOMAIR maintained an independent association with Hcy (p<0.05), irrespective of age and other anthropometric and biochemical variables. Lastly, we observed a gradual increase in Hcy plasma levels across the age- and BMI-matched quartiles in which the whole population was divided according to HOMAIR levels (F: 2.73, p<0.05 for linear trend). CONCLUSIONS: Our study shows that Hcy plasma levels are independently associated with IR in apparently healthy normal weight, overweight and obese pre-menopausal women, thus suggesting a possible role of IR and/or hyperinsulinaemia in increasing Hcy plasma levels. Since Hcy is a well-known cardiovascular risk factor, higher Hcy plasma levels may well be a further mechanism explaining the higher risk of coronary heart disease in patients affected by I

Enhancement of T cell-mediated immune responses to whole inactivated influenza virus by chloroquine treatment in vivo

Current influenza vaccines induce poor cross-reactive CD8+ T cell responses. Cellular immunity is generally specific for epitopes that are remarkably conserved among different subtypes, suggesting that strategies to improve the cross-presentation of viral antigens by dendritic cells (DC) could elicit a broadly protective immune response. Previous studies have shown that limited proteolysis within the endocytic pathway can favorably influence antigen processing and thus immune responses. Herein, we demonstrate that chloroquine improves the cross-presentation of non-replicating influenza virus in vitro and T cell responses in mice following a single administration of inactivated HI-X31 virus. CD8+ T cells were also recruited to lymph nodes draining the site of infection and able to reduce viral load following pulmonary challenge with the heterologous PR8 virus. These findings may have implications for vaccination strategies aimed at improving the cross-presentation capacity of DCs and thus the size of effector and memory CD8+ T cells against influenza vaccines