RESUMO
Rotavirus (RV) predominantly replicates in intestinal epithelial cells (IEC), and "danger signals" released by these cells may modulate viral immunity. We have recently shown that human model IEC (Caco-2 cells) infected with rhesus-RV release a non-inflammatory group of immunomodulators that includes heat shock proteins (HSPs) and TGF-ß1. Here we show that both proteins are released in part in association with membrane vesicles (MV) obtained from filtrated Caco-2 supernatants concentrated by ultracentrifugation. These MV express markers of exosomes (CD63 and others), but not of the endoplasmic reticulum (ER) or nuclei. Larger quantities of proteins associated with MV were released by RV-infected cells than by non-infected cells. VP6 co-immunoprecipitated with CD63 present in these MV, and VP6 co-localized with CD63 in RV-infected cells, suggesting that this viral protein is associated with the MV, and that this association occurs intracellularly. CD63 present in MV preparations from stool samples from 36 children with gastroenteritis due or not due to RV were analyzed. VP6 co-immunoprecipitated with CD63 in 3/8 stool samples from RV-infected children, suggesting that these MV are released by RV-infected cells in vivo. Moreover, fractions that contained MV from RV-infected cells induced death and inhibited proliferation of CD4(+) T cells to a greater extent than fractions from non-infected cells. These effects were in part due to TGF-ß, because they were reversed by treatment of the T cells with the TGF-ß-receptor inhibitor ALK5i. MV from RV-infected and non-infected cells were heterogeneous, with morphologies and typical flotation densities described for exosomes (between 1.10 and 1.18 g/mL), and denser vesicles (>1.24 g/mL). Both types of MV from RV-infected cells were more efficient at inhibiting T-cell function than were those from non-infected cells. We propose that RV infection of IEC releases MV that modulate viral immunity.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Exossomos/metabolismo , Proteínas de Choque Térmico/metabolismo , Mucosa Intestinal/virologia , Infecções por Rotavirus/imunologia , Fator de Crescimento Transformador beta1/metabolismo , Antígenos CD/metabolismo , Antígenos Virais/metabolismo , Western Blotting , Células CACO-2 , Proteínas do Capsídeo/metabolismo , Pré-Escolar , Epitopos/imunologia , Epitopos/ultraestrutura , Exossomos/imunologia , Feminino , Gastroenterite/imunologia , Gastroenterite/metabolismo , Gastroenterite/virologia , Proteínas de Choque Térmico/imunologia , Humanos , Imunidade Celular , Lactente , Masculino , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência , Glicoproteínas da Membrana de Plaquetas/metabolismo , Tetraspanina 30 , Fator de Crescimento Transformador beta1/imunologiaRESUMO
OBJECTIVE: To determine whether the Infant Behavioral Assessment and Intervention Program (IBAIP) improves development and behavior in very low birth weight (VLBW) infants at 24-month corrected age. STUDY DESIGN: In a multicenter, randomized, controlled trial 86 infants received postdischarge intervention until 6-month corrected age. The intervention consisted of supporting infants' self-regulation and development, and facilitating sensitive parent-infant interactions; 90 control infants received regular care. At 6 months, positive intervention effects were found. At 24 months, development and behavior were evaluated with the Bayley Scales of Infant Development-II (BSID-II) and the Child Behavior Check List (CBCL). RESULTS: Eighty-three intervention and 78 control infants were available for follow-up. After adjustment for differences in perinatal characteristics, an intervention effect of 6.4 points (+/- standard error, 2.4) on the Psychomotor Developmental Index favored the intervention infants. Groups did not differ on the Mental Developmental Index, the Behavioral Rating Scale of the BSID-II, or on the CBCL. Subgroup analyses revealed improved motor as well as improved mental outcomes in intervention infants with bronchopulmonary dysplasia and with combined biological and social risk factors. CONCLUSIONS: The IBAIP shows sustained motor improvement in VLBW infants until 2-year corrected age.
Assuntos
Desenvolvimento Infantil , Deficiências do Desenvolvimento/prevenção & controle , Intervenção Educacional Precoce , Comportamento do Lactente , Recém-Nascido de muito Baixo Peso , Exame Neurológico , Pré-Escolar , Feminino , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Masculino , Fatores de Risco , Fatores Socioeconômicos , Resultado do TratamentoRESUMO
OBJECTIVE: To determine whether the Infant Behavioral Assessment and Intervention Program (IBAIP), designed to support and enhance infants' self-regulatory competence, improved developmental and neurobehavioral outcomes in very low birth weight (VLBW) infants. STUDY DESIGN: We randomized 86 infants to 1 intervention before discharge and to 6 to 8 home interventions until 6 months corrected age, and 90 control infants received standard care. Developmental and behavioral outcomes were evaluated at 6 months corrected age with the Bayley Scales of Infant Development-II (BSID-II). Neurobehavioral functioning was evaluated with the Infant Behavioral Assessment (IBA) at baseline and at 6 months corrected age. RESULTS: Despite randomization, some differences in neonatal characteristics were found between the intervention and control infants. After adjustment, intervention effects of 7.2 points (+/- standard error 3.1) on the Mental Developmental Index and 6.4 +/- 2.4 points on the Psychomotor Developmental Index favored the intervention infants. The Behavioral Rating Scale of the BSID-II (P = .000) and the IBA (more approach [P = .003] and less stress [P = .001] over time) also favored the intervention infants. CONCLUSIONS: The IBAIP improved the mental, motor, and behavioral outcomes of VLBW infants at 6 months corrected age.