Activación de la célula T, alteraciones en el lupus eritematoso sistémico, una revisión narrativa / T-cell activation, alterations in systemic lupus erythematosus: A narrative review

Resumen La activación de los linfocitos T se inicia a través de la presentación de antígenos endógenos o exógenos por células presentadoras de antígenos a través del complejo mayor de histocompatibilidad, el cual se une a un receptor especializado presente en los linfocitos T. Este reconocimiento desencadena una cascada de señalización intracelular que conlleva a un aumento en la expresión de integrinas, modificaciones del citoesqueleto y producción de factores de transcripción involucrados en la liberación de citocinas y mediadores inflamatorios. Uno de los inductores más importantes en la activación celular es el complejo enzimático con acción tirosina cinasa. Las cinasas que pertenecen a la familia SRC (SFK), FYN y LCK están involucradas en un gran número de procesos importantes en la activación, modulación de la respuesta linfocitaria y el desarrollo de enfermedades autoinmunes. La regulación de la señalización de las cinasas, así como de proteínas adaptadoras involucradas en la activación del linfocito T, son fundamentales para mantener el umbral de activación y modulación de la respuesta del linfocito. La fosforilación de sitios de regulación positiva de estas proteínas es importante para permitir una configuración activa de la proteína y de esta forma su máxima capacidad como cinasa. La fosforilación de los sitios de regulación negativa conlleva a una configuración cerrada de la proteína de tal forma que reduce su función de cinasa e inhibe su función. Las alteraciones en la señalización por modificación de algunas proteínas citoplasmáticas se asocian en algunos casos al desarrollo de enfermedades autoinmunes, como el lupus eritematoso sistémico. En condiciones fisiológicas, el complejo receptor de linfocitos T se reagrupa con complejos proteicos que interactúan armónicamente para generar una sen al interna. Los eventos de señalización alterados son en parte los responsables de una expresión anómala de citocinas, entre ellas la interleucina-6 (IL-6), IL-10, IL-2, IFN y CD40 ligando; estas modificaciones alteran la capacidad de los linfocitos T para sobre estimular a los linfocitos B, traduciéndose en un aumento en la producción de autoanticuerpos y en el desencadenamiento de la enfermedad autoinmune.

Abstract The activation of T cells is initiated by the presentation of exogenous or endogenous antigens, by antigen presenting cells through the major histocompatibility complex, which binds to a special receptor on T cells. This acknowledgement triggers a cascade of intracellular signalling that leads to an increase in integrin expression, cytoskeletal modifications, and transcription factors production involved in the liberation of cytokines and inflammatory mediators. One of the most important inducers in cell activation is the enzymatic complex with tyrosine kinase action. The kinases which belong to the SRC (SFK) LCK and FYN family have been involved in a large number of important processes in the activation and modulation of the T cells response, as well as in the development of autoimmune diseases. Regulating the kinases signalling, as well as the adapter proteins involved in T cell activation, is essential for maintaining an activation threshold, as well as the modulation of cell response. The phosphorylation of the positive regulation sites of these proteins is important to allow an active configuration of the protein and thereby its maximum capacity as kinase. The phosphorylation of negative regulation sites leads to a closed configuration of the protein that reduces its kinase function, and thereby inhibits its own function. The alteration in signalling by the modification of certain cytoplasmic proteins in some cases is associated with the development of autoimmune diseases, such as systemic lupus erythematosus. Under physiological conditions the T cell receptor complex regroups with protein complexes that interact harmonically to generate an internal signal. The altered signalling events are partly responsible for an anomalous expression of cytokines, including the interleukin-6 (IL-6), IL-10, IL-2, IFN, and CD40 linking, these modifications affects the cells ability to over-stimulate T and B cells, resulting in an increased production of autoantibodies and the triggering of the autoimmune disease.

Combined immunodeficiency / 中华实用儿科临床杂志

Combined immunodeficiency (CID) is categorized to the first classification from the international union of immunological societies expert committee for primary immunodeficiency.Severe combined immunodeficiency (SCID) is the most fatal disorder for paediatric clinical operation.Without hematopoietic stem cell transplantation,almost all infants would die before 1 year old,few could survive beyond 2 years old.Hypomorphic mutations in SCID genes can lead to atypical phenotypes.The two special SCID should be focused,Omenn syndrome and graft-versus-host disease,which are caused by expension of autologous and maternal activated and memory T lymphocytes,respectively.Patients with radiosensitive-CID usually present later on life,for whom treatment should be monitored carefully.CID caused by T cells with normal development and inborn error was hotspot research field for example zeta chain-associated protein 70 kDa deficiency.More attention should be paid to CID associated with syndromes for example dedicator of cytokinesis 8 deficiency.Now,the pathogenesis,molecular,clinical,laboratory features and treatment and prognosis are described,in order to support clues for paediatrician's clinical practice.

Ovarian carcinoma cells inhibit ? chain expression and the secretion of Tc1/Tc2 type cytokines in CD8~+ T cells / 中国病理生理杂志

AIM:To investigate the effect of ovarian carcinoma cells on ? chain expression and the secretion of Tc1/Tc2 type cytokine in CD8+ T cells,and its role in the ovarian carcinoma induced immunosuppression.METHODS:The supernatants of human ovarian carcinoma cell lines of OVCAR3,CAOV3 and SKOV3 and RPMI-1640 were added into CD8+ T cells(groups I,II,III,and control),which were isolated from the peripheral venous blood of healthy persons.The expression of ? chain was analyzed by Western blotting.Thiazolyl blue(MTT)method was used to detect the effects of those cell line supernatants on the growth of CD8+ T cells.The secretion of the Tc1 type cytokine interferon(IFN)-? mRNA and the Tc2 type cytokine interferon(IL)-10 mRNA were detected by RT-PCR.RESULTS:The expression of ? chain was significantly lower in groups I,II,and III in comparison with that in control group.The absorbance at the wavelength 570 nm of CD8+ T cells culture in the group I,II,and III was all significantly lower than that in the control group.The IFN-? expression was significantly lower in groups I,II,and III in comparison with that in control group,while the expression of IL-10 was significantly higher.CONCLUSION:Ovarian carcinoma may suppress CD8+ T cell proliferation and secretion of the Tc1/Tc2 type cytokine through inhibition of ? chain,which may play an important role in the ovarian carcinoma induced immunosuppression.