RESUMEN
Follicular helper T cells (TFHs) are a key component of adaptive immune responses as they help antibody production by B cells. Differentiation and function of TFH cells are controlled by the master gene BCL6, but it is largely unclear how this transcription repressor specifies the TFH program. Here we asked whether BCL6 controlled helper function through down-regulation of specific microRNAs (miRNAs). We first assessed miRNA expression in TFH cells and defined a TFH-specific miRNA signature. We report that hsa-miR-31-5p (miR-31) is down-regulated in TFH; we showed that BCL6 suppresses miR-31 expression by binding to its promoter; and we demonstrated that miR-31 inhibits the expression of molecules that control T-helper function, such as CD40L and SAP. These findings identify a BCL6-initiated inhibitory circuit that stabilizes the follicular helper T cell program at least in part through the control of miRNA transcription. Although BCL6 controls TFH activity in human and mouse, the role of miR-31 is restricted to human TFH cell differentiation, reflecting a species specificity of the miR-31 action. Our findings highlight miR-31 as a possible target to modulate human T cell dependent antibody responses in the settings of infection, vaccination, or immune dysregulation.
Asunto(s)
Linfocitos B/inmunología , Ligando de CD40/genética , MicroARNs/genética , Proteínas Proto-Oncogénicas c-bcl-6/genética , Proteína Asociada a la Molécula de Señalización de la Activación Linfocitaria/genética , Linfocitos T Colaboradores-Inductores/inmunología , Inmunidad Adaptativa , Animales , Linfocitos B/citología , Ligando de CD40/inmunología , Diferenciación Celular , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Redes Reguladoras de Genes , Centro Germinal/citología , Centro Germinal/inmunología , Humanos , Ratones , Ratones Endogámicos C57BL , MicroARNs/inmunología , Cultivo Primario de Células , Regiones Promotoras Genéticas , Unión Proteica , Proteínas Proto-Oncogénicas c-bcl-6/inmunología , Transducción de Señal , Proteína Asociada a la Molécula de Señalización de la Activación Linfocitaria/inmunología , Especificidad de la Especie , Linfocitos T Colaboradores-Inductores/citologíaRESUMEN
Accumulating experimental and clinical evidence has been obtained over recent years in support of the notion that the immune system has the potential to cure cancer. The most convincing example is the graft versus leukaemia effect observed after allogeneic haematopoietic stem cell transplantation. In the autologous setting, however, the isolation and expansion of naturally occurring tumour-specific T cells is a challenging task. Cancer antigens are often self-antigens and cancer-specific T cells are thus subject to selective mechanisms of central and peripheral tolerance. The significant advances in gene-transfer technologies developed over the last decade have offered new tools to overcome these limitations. Natural T cells can be genetically modified to generate high numbers of 'supernatural' tumour-reactive T cells from virtually every cancer patient. Supernatural T cells may express clonal receptors providing new specificities, factors increasing T-cell performance or safety factors enabling their elimination in case of toxicity. Technological improvements applied to novel concepts of T-cell biology and oncogenesis will allow to simultaneously equip T cells with different transgenes and expand a real 'army' of lymphocytes trained to selectively eradicate cancer cells.
Asunto(s)
Antígenos de Neoplasias , Ingeniería Genética , Efecto Injerto vs Leucemia/genética , Neoplasias Hematológicas , Trasplante de Células Madre Hematopoyéticas , Linfocitos T , Animales , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/metabolismo , Neoplasias Hematológicas/genética , Neoplasias Hematológicas/terapia , Humanos , Linfocitos T/metabolismo , Linfocitos T/trasplante , Trasplante HomólogoRESUMEN
The importance of AR for a prompt and upkeep therapy is underlined by the Authors on the base of a statistical and clinical study about 67 cases of thoracic trauma treated from January 1975 to November 1979. The different alteration of the chest wall and surrounding structures are taken into consideration. The possible association of thoracic trauma with head trauma, severe shock and bony traumatism are also considered from a statistical and from a clinical point of view. The various therapeutic measures in case of thoracic trauma are also mentioned.