RESUMO
While CD28 is critical for expansion of naive T cells, recent evidence suggests that the activation of effector T cells is largely independent of CD28/B7. We suggest that ICOS, the third member of the CD28/CTLA-4 family, plays an important role in production of IL-2, IL-4, IL-5, and IFNgamma from recently activated T cells and contributes to T cell-dependent B help in vivo. Inhibition of ICOS attenuates lung mucosal inflammation induced by Th2 but not Th1 effector populations. Our data indicate a critical function for the third member of the CD28 family in T cell-dependent immune responses.
Assuntos
Antígenos de Diferenciação de Linfócitos T/imunologia , Antígenos CD28/imunologia , Imunoconjugados , Células Th1/imunologia , Células Th2/imunologia , Abatacepte , Animais , Antígenos CD , Antígenos de Diferenciação/imunologia , Antígenos de Diferenciação de Linfócitos T/genética , Antígeno CTLA-4 , Clonagem Molecular , Citocinas/biossíntese , Expressão Gênica , Humanos , Imunoglobulina G/biossíntese , Imunoglobulina M/biossíntese , Proteína Coestimuladora de Linfócitos T Induzíveis , Células Jurkat , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Transdução de SinaisRESUMO
A systemic reappraisal of the thermic effect of food was done in lean and obese males randomly fed mixed meals containing 0, 8, 16, 24, and 32 kcal/kg fat-free mass. Densitometric analysis was used to measure body composition. Preprandial and postprandial energy expenditures were measured by indirect calorimetry. The data show that the thermic effect of food was linearly correlated with caloric intake, and that the magnitude and duration of augmented postprandial thermogenesis increased linearly with caloric consumption. Postprandial energy expenditures over resting metabolic requirements were indistinguishable when comparing lean and obese men for a given caloric intake. Individuals, however, had distinct and consistent thermic responses to progressively greater caloric challenges. These unique thermic profiles to food ingestion were also independent of leanness or obesity. We conclude that the thermic effect of food increases linearly with caloric intake, and is independent of leanness and obesity.
Assuntos
Regulação da Temperatura Corporal , Ingestão de Energia , Alimentos , Obesidade/metabolismo , Adulto , Composição Corporal , Peso Corporal , Calorimetria , Densitometria , Metabolismo Energético , Humanos , MasculinoRESUMO
The resting metabolic rates (RMR) of 60 lean and obese men, aged 18-82 y and weighing 60-171 kg, were measured and body compositions were determined. Body compositional variables reflecting active protoplasmic tissue were all highly interrelated. Body weight alone gave prediction values for RMR that were comparable to those of other variables of active protoplasmic tissue mass. Regional distribution of fat had no influence on the RMR and the influence of age on RMR was trivial. The classic prediction equations and tables overestimate RMR of men. The 95%-confidence limits for both lean and obese men were broad. This conclusively demonstrates that metabolic efficiency is not necessarily or exclusively related to obesity. New regression equations for predicting the RMR based on weight and fat-free mass were developed: RMR = 879 + 10.2 WT kg and RMR = 290 + 22.3 FFMD kg, where FFMD is fat-free mass from densitometry measurements.
