Galt y translocacion bacteriana
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Inmunidad intestinal Sistema GALT Translocacion bacteriana
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Galt y translocacion bacteriana
- 1. Universidad de CartagenaMayo, 2016 Ana Santos Arrieta Estudiante de Posgrado I Nivel Cirugía General Sistema GALT y Translocation Bacteriana
- 2. La Inmunidad en las Mucosas Primer to Inmune Response. Second Edition 2014 by Mak. Ed Elsevier Rev Fac Med UNAM Vol. 52 No. 5, 2009 MALT Agrupación de células linfoides sin organización o estructura, que se encuentra asociado a la mucosa y que forma parte de una serie de localizaciones linfoides repartidas por el organismo
- 3. Células del sistema inmunitario innato y adaptativo En el adulto, 80% de todas las células inmunitarias del organismo Organo linfoide más grande de los mamíferos. Estructuras linfoides no encapsuladas Localización en la lámina propia y submucosas MALT
- 4. Proteger las mucosas contra microorganismos patógenos invasores Promotora de la TOLERANCIA Prevenir la captación de antígenos extraños de los alimentos, microorganismos comensales y microorganismos patógenos Prevenir las respuestas inmunitarias patológicas de antígenos extraños si atraviesan las barreras mucosas del cuerpo. Mediador de la relación simbiótica entre comensales y hospedador MALT Middlenton´s Allergy: Principles and Practice. Eighth Edition 2014 by Saunders. Ed Elsevier
- 5. El Tracto GastroIntestinal Middlenton´s Allergy: Principles and Practice. Eighth Edition 2014 by Saunders. Ed Elsevier
- 6. Tracto Gastrointestinal : Absorcion de nutrientesExcresion de productos de desecho Participacion activa inmunologica contra microorganismos patogenos y desarrollar tolerancia Middlenton´s Allergy: Principles and Practice. Eighth Edition 2014 by Saunders. Ed Elsevier
- 7. Tracto Gastro-Intestinal Enterocitos Celulas caliciformes Celulas de paneth Celulas enteroendocrinas Productoras de mucus, esta forma una capa fluida y movil, que es protectora y dificulta la adherencia de los microorganismos al epitelio intestinal Productoras de serotonina, somatostatina, motilin, peptido intestinal vaso activo Se encargan de la absorción de nutrientes y transportarlos al interior del organismo Secretan peptidos antimicrobianos (defencinas tales como criptidinas y catelicidinas) Middlenton´s Allergy: Principles and Practice. Eighth Edition 2014 by Saunders. Ed Elsevier
- 8. Organizado • Folículos linfoides aislados • Placas de Peyer • Ganglios linfáticos mesentéricos Difuso • Poblaciones de linfocitos dispersas en el entramado intraepitelial o lamina propia intestinal GALT Middlenton´s Allergy: Principles and Practice. Eighth Edition 2014 by Saunders. Ed Elsevier Rev Fac Med UNAM Vol. 52 No. 5, 2009
- 9. Agregados linfoides macroscópicos antimesentericos Aislado del lumen por una capa de células ( follicle associated epithelium FAE) Celulas epiteliares columnares Celulas M IEL Celulas caliciformes Por debao de esta yace una región difusa denominada cúpula subepitelial Celulas dendríticas Macrofagos Placas de Peyer Linfocitos B IgM +> Linfo B IgA productores> Cel plasmáticas IgA+ Area interfolicular Linfo T (Th), células dendríticas y macrofagos Placas de Peyer Rev Fac Med UNAM Vol. 52 No. 5, 2009
- 10. Tejido Linfoide Asociado a Intestino
- 11. Ganglios Linfáticos Mesentericos Linf B y C. dendriticas Corteza Linf T y C dendriticas Paracorteza Linf T y B, C. plasmáticas Medula Rev Fac Med UNAM Vol. 52 No. 5, 2009
- 12. Presentación Antigénica Primer to Inmune Response. Second Edition 2014 by Mak. Ed Elsevier
- 13. Integración GALT Primer to Inmune Response. Second Edition 2014 by Mak. Ed Elsevier
- 14. Inmunoglobulina A Primera defensa frente a toxinas y colonización e invasión de patógenos Representa 80-90% de las Igs de la mucusa Evita penetración de microorganismos intraluminales y antígenos a la dieta. Producción: >50 mg/Kg/24 h Rev Fac Med UNAM Vol. 52 No. 5, 2009
- 15. Inmunoglobulina No inflamatoria Débil unión al complemento. En plasma se encuentra en forma monomerica, en mucosas en forma dimerica-tetramerica Componente “secretor” la protege de acción enzimática Asociación a barrera de moco Inmunoglobulina A Primer to Inmune Response. Second Edition 2014 by Mak. Ed Elsevier
- 16. Microflora Intestinal Comunidad de microorganismos vivos reunidos en un nicho ecológico determinado • Especies nativas • Especies de tránsito temporal 100 billones de bacterias Distribución • Estómago y duodeno número reducido • Yeyuno e íleon Aerobios gram negativos • Colon Anaerobios Nutr Hosp. 2007;22(Supl. 2):50-5
- 18. Funciones de Microbiota Nutrición Protección Tróficas Nutr Hosp. 2007;22(Supl. 2):50-5
- 19. Translocación Bacteriana Paso o movimiento de bacterias y/o productos bacterianos, de la luz intestinal a territorio extraintestinal Factores • Hipoxia celular • Lesión tisular inducida por mediadores • Efecto tóxico de las bacterias Nutr Hosp. 2007;22(Supl. 2):50-5
- 20. Mecanismo de Translocación Bacteriana Alteración microflora gastrointestinal • Sobrecrecimiento bacteriano Disrupción física de la barrera intestinal • Lesión directa • Hipoperfusión Alteración defensas del huésped. Nutr Hosp. 2007;22(Supl. 2):50-5
- 21. Mecanismo de Translocación Bacteriana Rev Méd Chile 2006; 134: 1033-1039
- 22. Vía de Translocacion Bacteriana Migración retrógrada a los pulmones Migración transmural directa Migración a través de: • GALT • Conducto torácico • Circulación sistémica • Circulación portal Nutr Hosp. 2007;22(Supl. 2):50-5
Notas del editor
- The mucosa-associated lymphoid tissue (MALT) and skin-associated lymphoid tissue (SALT) mount mucosal and cutaneous responses, respectively, to protect the body tracts and skin. The MALT and SALT are made up of collections of APCs and lymphocytes that are located just under the mucosae or skin, respectively. These collections function as independent arms of the immune system that are responsible for mucosal immune responses and cutaneous immune responses . Mucosal and cutaneous responses are distinct from the systemic immune responses discussed so far in this book, i.e., those responses most often initiated by lymphocyte–APC interaction in a draining lymph node or the spleen. The majority of mucosal and cutaneous immune responses are mounted locally where antigen is first encountered—that is, without being conveyed to a draining lymph node via its afferent lymphatics. The effector cells that are generated may enter efferent lymphatics or the circulation but then home specifically to mucosal and cutaneous sites to exert their effector functions. However, an accompanying systemic immune response in which effector cells attack the antigen in other locations throughout the body can be induced when antigen-bearing APCs of the MALT or SALT migrate to the local draining lymph node and activate naïve T and B cells in this location. Overview Ir a: Esquema Primer to The Immune Response Second Edition Copyright © 2014 Elsevier Inc. All rights reserved. Obtener derechos y contenido CAPÍTULO Mucosal and Cutaneous Immunity Descargar PDF Tak W. Mak y Bradley D. Jett Primer to The Immune Response, Chapter 12, 269-292 Abrir en modo de lectura Abstract The mucosa-associated lymphoid tissue (MALT) and skin-associated lymphoid tissue (SALT) mount mucosal and cutaneous responses, respectively, to protect the body tracts and skin. Most mucosal and cutaneous responses are initiated locally at inductive sites, and any lymphocytes activated can then home to more distant effector sites. Anatomical barriers, secretory IgA (SIgA), and innate leukocytes provide initial defense in the MALT. M cells in the follicle-associated epithelium (FAE) of inductive sites capture pathogens and convey them to mucosal APCs and T cells in domes covering B cell-containing lymphoid follicles. DCs also capture antigen via transepithelial dendrites. Effector lymphocytes migrate to multiple mucosal effector sites to provide coordinated protection via the “common mucosal immune system.” Immune responses in the MALT are biased toward SIgA to reduce inflammatory damage to fragile mucosae; however, aggressive pathogens trigger more inflammatory Th1/Th17 responses. The SALT consists of diffuse collections of innate leukocytes and T cells in the epidermis and dermis. Keratinocytes provide an overlying physical barrier and secrete pro-inflammatory cytokines/chemokines that activate phagocytes and specialized antigen-presenting cells called Langerhans cells. Antigens are presented locally to activate epidermal memory T cells or are conveyed to naïve T cells in the local lymph node. Effector T cells generated can then home to skin sites under attack. While the skin is protected by Th1/Th17 responses initially, a persistent pathogen can trigger macrophage hyperactivation resulting in tissue damage. Keywords mucosa-associated lymphoid tissue, MALT, skin-associated lymphoid tissue, SALT, M cell, follicle-associated epithelium, common mucosal immune system, secretory IgA, Langerhans cells, keratinocyte What’s in this Chapter? A. Mucosal Immunity 269 I. Overview 269 II. Components of the Gut-Associated Lymphoid Tissue (GALT) 271 III. Components of Nasopharynx- and Bronchi-Associated Lymphoid Tissues (NALT and BALT) 275 IV. Immune Responses in the GALT, NALT and BALT 277 V. Immune Responses in Other MALT 284 B. Cutaneous Immunity 285 I. Components of the Skin-Associated Lymphoid Tissue (SALT) 285 II. Immune Responses in the SALT 287 Most human pathogens gain access to the body by penetrating its skin or mucosae. In Chapter 2 , we introduced the concepts of the MALT (mucosa-associated lymphoid tissue) and SALT (skin-associated lymphoid tissue). The MALT and SALT are made up of collections of APCs and lymphocytes that are located just under the mucosae or skin, respectively. These collections function as independent arms of the immune system that are responsible for mucosal immune responses and cutaneous immune responses . Mucosal and cutaneous responses are distinct from the systemic immune responses discussed so far in this book, i.e., those responses most often initiated by lymphocyte–APC interaction in a draining lymph node or the spleen. The majority of mucosal and cutaneous immune responses are mounted locally where antigen is first encountered—that is, without being conveyed to a draining lymph node via its afferent lymphatics. The effector cells that are generated may enter efferent lymphatics or the circulation but then home specifically to mucosal and cutaneous sites to exert their effector functions. However, an accompanying systemic immune response in which effector cells attack the antigen in other locations throughout the body can be induced when antigen-bearing APCs of the MALT or SALT migrate to the local draining lymph node and activate naïve T and B cells in this location. A Mucosal Immunity I Overview As introduced in earlier chapters, the mucosae are relatively thin layers of epithelial cells that line a body passage such as the gut, respiratory tract or urogenital tract. In adult humans, the area of all these mucosae exceeds 400 m 2 ! Histologists have identified two categories of mucosae that differ in their epithelial structures. Type I mucosae , such as occur in the gut and lungs, are composed of a single layer of columnar epithelial cells. Type II mucosae are found where tougher tissue is required, such as in the mouth, nose and vagina, and are characterized by a top layer of flat, scale-like squamous epithelial cells . Both types of mucosae get their name from their capacity to produce mucus , a very viscous solution of polysaccharides in water that covers the apical (lumen-facing) membrane of an epithelial cell. Mucus contains various antibodies, predominantly SIgA in type I mucosae and IgG in type II mucosae, as well as antimicrobial molecules that help protect the mucosae from pathogen invasion. These antimicrobial molecules include lysozyme, which breaks down cell wall components, and lactoferrin, which sequesters iron needed for bacterial growth. As well as by mucus, the mucosae are constantly defended against pathogen assaults by immune responses mounted in the MALT. The MALT includes several subsystems of lymphoid elements associated with each of the body tracts. These subsystems, which differ in structure and cellular composition, are called the GALT, NALT and BALT based on their locations in the gut, nasopharynx and bronchi, respectively ( Table 12-1 ). TABLE 12-1 The “ALTs” System NameSubsystemDefinitionTissue DefendedMALTMucosa-associated lymphoid tissueMucosae of body tractsGALTGut-associated lymphoid tissueMucosae of small and large intestinesNALTNasopharynx-associated lymphoid tissueMucosae of nose, tonsils, throatBALTBronchi-associated lymphoid tissueMucosae of bronchi and bronchioles in the lungsSALTSkin-associated lymphoid tissueSkin on body surface Scientists working in the MALT field speak of inductive sites and effector sites ( Fig. 12-1 ). Aninductive site is a specific area in a mucosa where an antigen is encountered and a primary adaptive response is initiated. Inductive sites in the GALT include organized lymphoid structures in the small intestine called Peyer’s patches (PPs) , the appendix, and diffuse collections of lymphocytes and APCs scattered within and just under the gut epithelium. A mucosal effector site is a specific area in a mucosa to which effector lymphocytes are dispatched. Among the most important mucosal effector sites are the exocrine glands , such as the salivary and lacrimal glands. These glands produce protective external secretions (like saliva and tears) that contain antimicrobial molecules and secretory antibodies. After mucosal T and B cells are activated in a given inductive site, they migrate through the lymphatics and blood to various effector sites and complete their differentiation into Th effectors, CTLs and plasma cells in these locations. Thus, defense at multiple and widely separated mucosal effector sites may occur in response to lymphocyte activation in one inductive site. For example, when an antigen is captured in a PP (inductive site), an antibody response may be detected not only in the intestinal mucosa but also in the urogenital tract and in tissues as remote as the mammary glands (effector sites). This concept is referred to as the common mucosal immune system Most mucosal and cutaneous responses are initiated locally at inductive sites, and any lymphocytes activated can then home to more distant effector sites. Anatomical barriers, secretory IgA (SIgA), and innate leukocytes provide initial defense in the MALT. M cells in the follicle-associated epithelium (FAE) of inductive sites capture pathogens and convey them to mucosal APCs and T cells in domes covering B cell-containing lymphoid follicles. DCs also capture antigen via transepithelial dendrites. Effector lymphocytes migrate to multiple mucosal effector sites to provide coordinated protection via the “common mucosal immune system.” Immune responses in the MALT are biased toward SIgA to reduce inflammatory damage to fragile mucosae; however, aggressive pathogens trigger more inflammatory Th1/Th17 responses
- The gastrointestinal (GI) tract has the unique characteristic of being the largest organ exposed to external antigens ( Fig. 67-1 ). It is multifunctional and serves as a mucosal barrier, an absorptive surface, and a site of active immunity to foreign antigens. The normal structural and functional components of the gastrointestinal immune system are the focus of this chapter. From the protective layer of mucus to the specialized mucosal epithelium and the deeper immune aggregates, the GI tract requires precise regulation to balance immune reactions against foreign antigens while fostering the symbiotic, commensal microbiota. The innate and adaptive immune systems act in concert to hold the GI mucosal immune system in a state of tolerance to benign antigens while maintaining an appropriate capacity to respond to pathogenic insults.
- Uptake of antigens across epithelial surface. Antigens can cross the epithelial surface by at least three routes: A,passage through the M cells that overlie Peyer patches; B, transcellularly; or C, paracellularly through epithelia to underlying T cells or macrophages; and capture by dendritic cell ( DC ) processes that extend between epithelial cells.
- Intestinal mucosa overview. The epithelial surface is exposed to an abundant and diverse microbiome. To protect itself, it is coated with mucus that contains trefoil proteins, secretory IgA, and antimicrobial peptides. Antigens may pass through the epithelial surface and undergo processing in Peyer patches. Within the subepithelial dome (SED)reside a number of lymphocytes, including natural helper T (Th0) cells, which can differentiate into type 1 (Th1), type 2 (Th2), regulatory (Treg), or Th17 cells. Other resident cells include macrophages, cytotoxic lymphocytes, mast cells ( MC ), eosinophils ( EOS ), and dendritic cells ( DC ). IEL, Intraepithelial lymphocytes; MHC, major histocompatibility complex.