Video Experimental Relacionado
Updated: Aug 11, 2026
14:29
Examination of Thymic Positive and Negative Selection by Flow Cytometry
Published on: October 8, 2012
Un subconjunto de timocitos CD4+ seleccionados por moléculas MHC clase I
A Bendelac1, N Killeen, D R Littman
1Laboratory of Cellular and Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892.
Science (New York, N.Y.)
|March 25, 1994
Resumen
La mayoría de los timocitos maduran a través de las señales de los receptores de antígenos y los coreceptores CD4/CD8. Un subconjunto único de células T madura independientemente de CD4 o CD8, revelando nuevas vías de desarrollo de timocitos.
Área de la Ciencia:
- Inmunología Inmunología.
- Biología celular Biología celular.
- Biología del desarrollo Biología del desarrollo.
Sus antecedentes:
- La maduración de los timocitos requiere típicamente el compromiso simultáneo del receptor de células T alfa beta (TCR) con los coreceptores CD4 o CD8 y sus respectivos ligandos MHC.
- Este proceso dicta el compromiso del linaje de desarrollar células T en subconjuntos CD4+ o CD8+.
Objetivo del estudio:
- Para investigar el proceso de maduración de un subconjunto distinto de timocitos alfa beta TCR+ maduros que se desvían de las reglas convencionales de maduración.
- Aclarar el papel de los coreceptores CD4 y CD8 en la selección y maduración de estos timocitos no convencionales.
Principales métodos:
- Análisis de poblaciones de timocitos que expresan NK1.1 y TCRs alfa beta restringidos.
- Investigación de los mecanismos de selección positivos y negativos en relación con las interacciones del MHC clase I y los coreceptores CD8.
- Citometría de flujo para evaluar la expresión de CD4 y CD8 en los timocitos en desarrollo.
Principales resultados:
- Un subconjunto normal de timocitos alfa beta TCR+ maduros expresa NK1.1 y posee TCRs intrínsecamente reactivos de clase I.
- La selección positiva de estas células depende de la clase I del MHC pero es independiente de la CD8.
- Estos timocitos maduran en linajes CD4+ y CD4-8-, y el compromiso de CD8 conduce a la selección negativa.
Conclusiones:
- Ni la señalización CD4 ni CD8 es necesaria para la maduración de este subconjunto específico de timocitos en linajes CD4+ y CD4-8-.
- Este hallazgo revela una vía alternativa de desarrollo de células T independiente de las señales de selección mediadas por CD4/CD8 canónicas.
Videos de Conceptos Relacionados
01:40Cell-mediated Immune Responses
Overview
01:26Antigens Involved in Adaptive Immunity
An antigen is any substance the immune system identifies as foreign and potentially harmful to the body, prompting an immune response. Antigens have two functional properties: immunogenicity and reactivity. Immunogenicity is the ability of an antigen to stimulate a specific immune response. At the same time, reactivity describes the antigen's ability to react with the cells and antibodies produced in response to it.
Complete Antigens
Complete antigens possess both immunogenicity and reactivity.
Complete Antigens
Complete antigens possess both immunogenicity and reactivity.
01:31Antigen Processing Pathways
MHC molecules are key players in the immune response, enabling T cells to recognize and respond to specific antigens. They are present on the surface of all nucleated cells in the body and are instrumental in presenting antigens to T cells and activating them. T cells recognize the MHC-antigen complex and initiate an immune response. MHC class I and MHC class II are two main types of MHC molecules, each associated with a distinct antigen processing pathway.
MHC Class I: Presenting Endogenous...
MHC Class I: Presenting Endogenous...
01:22T Cell Activation and Clonal Selection
T cells are integral to our adaptive immune system, recognizing and effectively responding to foreign antigens. T cell activation and clonal selection are pivotal in orchestrating this immune response. This article elucidates these mechanisms, detailing the roles of cluster of differentiation (CD) markers, major histocompatibility complex (MHC) molecules, costimulatory signals, and the process of clonal selection.
Naive T cells that have not yet encountered an antigen express two primary CD...
Naive T cells that have not yet encountered an antigen express two primary CD...
01:24T Cell Types and Functions
When T cells with CD4 markers are activated, they give rise to two types of effector cells: helper T cells and regulatory T cells. Meanwhile, T cells with CD8 markers differentiate into effector cytotoxic T cells. The differentiation of CD4 T cells into helper T cell subsets, such as Th1, Th2, and Th17 cells, is dependent on the antigen type, antigen-presenting cell, and regulatory cytokines.
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
01:27Cytotoxic T Cells-mediated Immune Response
Cytotoxic T cells are a vital component of the immune system. They have the remarkable ability to identify and target antigens on infected or abnormal cells. These antigens often originate from intracellular pathogens such as viruses or abnormal proteins cancer cells produce.
Immunological surveillance is the ability of immune cells to monitor and eliminate infected cells with intracellular pathogens, neoplastically transformed cells, and cells with non-self antigens. Cytotoxic T cells and NK...
Immunological surveillance is the ability of immune cells to monitor and eliminate infected cells with intracellular pathogens, neoplastically transformed cells, and cells with non-self antigens. Cytotoxic T cells and NK...