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.

Effect of Bromocriptine on the Activation of T Lymphocyte Stimulated by Phytohemagglutinin / 实用儿科临床杂志

Objective To study the effect of bromocriptine(BRC) on the activation of T lymphocyte stimulated by phytohemagglutinin(PHA).Methods After CD4+ T cell line Jurkat E6-1 cells were stimulated by PHA,prolactin(PRL) and BRC,respectively,the expression of linker for activation of T cells(LAT) and zeta-chain T cell receptor associated protein kinase 70 000(ZAP-70) mRNA of T lymphocytes were checked by RT-PCR.The expression of PRL mRNA of T lymphocytes was detected by Real time PCR.The expression of CD25(cluster of differentiation) as a marker of early activation on the surface of T lymphocytes was detected by flow cytometry,and the activation of nuclear factor-?B(NF-?B) was detected by luciferase reporter system.Results 1.BRC inhibited the expression of ZAP-70 as the common signal molecules both in the T lymphocyte activation pathway and PRL-prolactin-prolactin receptor(PRLR) signal transduction pathway,and decreased the expression of PRL mRNA produced by activation T lymphocytes.2.BRC enhanced the expression of LAT mRNA as another important signal molecular on the T lymphocytes and CD25 on the surface of the T lymphocytes.3.The activation of NF-?B of T lymphocytes was decreased.Conclusions BRC might inhibit the activation of T lymphocytes by inhibiting the expression of ZAP-70,the common signal molecules between T lymphocytes activation and PRL-PRL pathway,and PRL mRNA,the like-T lymphocyte growth factor.

The preliminary study on the effect of CTLA4-Ig on T cell function and its mechanism / 中国免疫学杂志

Objective:To study the inhibited function of CTLA4 Ig on T cell activation and its mechanism Methods:After separating fresh PBMC,the effects of CTLA4 Ig on T lymphocyte transformation and mixed lymphocyte reaction were analyzed,and its inhibitory effect on the CD25 expression on T cell surface was observed At last,the changes of the nuclear protein in active T cell were analyzed by the EMSA method.Results:CTLA4 Ig has an inhibitory effect on the lymphocyte transformation,MLR and CD25 expression on T cell surface,and it can inhibite the activation of RE/AP binding factor related to IL 2 expression. Conclusion:CTLA4 Ig inhibit the activation of T cell by multipathway,one of the mechanism might be its inhibitory effect on the activation of RE/AP binding factor.

Expressions of CD28 and CTLA-4 in peripheral blood and synovial fluid lymphocytes in patients with rheumatoid arthritis and the significance / 第三军医大学学报

Objective To study the expressions of co stimulatory factors CD28 and CTLA 4 on CD3 + T cells in peripheral blood lymphocytes (PBMC) and synovial fluid lymphocytes (SFMC) in patients with rheumatoid arthritis (RA) and the relationship of these molecules with the activity of RA. Methods The lymphocytes were collected from the peripheral blood and synovial fluid in RA patients. The CD3 +CD28 + and CD3 +CTLA 4 + molecules on these cells were measured by dual color fluorescence cytometry. The correlation of the expressions of CD3+CD28+ and CD3 +CTLA 4 + molecules with the activity of RA was statistically analyzed by Spearman. Results ① The level of CD3 +CD28 + in PBMC of RA patients was significantly lower than that of the control group and SFMC ( P