Tejido linfático asociado a mucosas: Células presentadoras de antígenos / Mucose associated lymphoid tissue: Antigen presenting cells

Se estudiaron al microscopio electrónico biopsias de mucosas normales y patológicas (cavidad bucal y cuello uterino), con especial atención a los sistemas de defensa existentes en las células epiteliales (CE) y en las células dendríticas (CD). Las CE, cuando están activadas, muestran su capacidad de fagocitar y procesar antígenos con la finalidad de presentarlos luego a las CD; los elementos implicados en esta función son vesículas de micropinocitosis, cuerpos multivesiculares, lisosomas, fagosomas, vesículas recubiertas por clatrina, gránulos de contenido denso recubiertos por una unidad de membrana, gránulos en cuyo interior se aprecian láminas que simulan hojas de cebolla, microcuerpos y gránulos con actividad de fosfatasa ácida. Las CD que recién han ingresado al interior del epitelio son de baja densidad electrónica y poseen grandes prolongaciones citoplasmáticas, que luego se reducen de tamaño, a la vez que aumenta la densidad de su citoplasma. Muestran vesículas de micropinocitosis, algunas recubiertas por clatrina, lisosomas y corpúsculos de Birberk. En este momento son reconocidas como células de Langerhans. Tanto en las CE como en las CD existen abundantes “pliegues marginales o de superficie“ (surface folds), conteniendo numerosas vesículas de micropinocitosis. Entre la CE y la CD se establecen íntimos contactos a través de los cuales las primeras presentan los antígenos fagocitados y tratados a las CD donde son terminados de procesar y se unen a las moléculas del complejo principal de histocompatibilidad y/o a moléculas con función similar (CD1). Las CD migran a los ganglios linfáticos donde presentan los antígenos a los linfocitos T y empieza el proceso de activación de estos, que conduce a la defensa frente a las noxas que han ingresado al organismo. De esta manera tanto las CD como las CE son un lazo de unión entre los sistemas de defensa innata y la adquirida.

We studied samples of normal and abnormal human mucosae, including oral tissue and uterine cervix, using electron microscopy. Special attention was given to the functions and mechanisms of defense carried out by the epithelial (EC) and dendritic cells (DC). Activated epithelial cells posses the capacity to uptake and process antigens, in order to present them, subsequently, to the dendritic cells. The structures and elements of the cells intervening on this function are: micropinocytic vesicles, multivesicular bodies, lysosomes, phagosomes, clathrin-covered vesicles, dense granules covered by a unit membrane, granules with onion likes leaves, microbodies, and dense granules with acid phosphatase activity. When they first arrive within the epithelial layers, the DC are clear with long cytoplasmic projections, which later become short, and the density of their cytoplasm increases. They possess mycropinocytic vesicles, some clathrine-covered vesicles, lysososmes and Birbeck granules. At this moment, they are known as Langerhans cells. EC and DC present many surface folds rich in micropynocytic vesicles. Between EC and DC there are many contacts (close junctions or tight junctions), through which antigens, phagocitized and processed by the EC, are given to the DC. These cells join them to major histocompatibility complex molecules or to other molecules with similar functions (CD1). Then the Langerhans cells travel to the lymphatic node to activate T cells and continue the immunologic task. So, in this way, both the EC and the DC are a link between the natural and the acquired immunological mechanisms.

Distribution and Quantification of Lymphocytes in the Major Lymphoid Organs of Naturally Gumboro Infected Broilers / Distribución y Cuantificación de Linfocitos en los Órganos Linfoides Principales de Pollos de Engorda Infectados Naturalmente con Gumboro

Gumboro disease is caused by the infectious bursal disease virus (IBDV) which rapidly destroys immature B-lymphocytes of bursa of Fabricious, and causes immune suppression and high mortality in commercial broiler farms in Bangladesh. To investigate the possible effect of IBDV on lymphocytes and its distribution in the major lymphoid organs, bursa of Fabricious including spleen and thymus of naturally Gumboro-infected broilers, a research was conducted in the Department of Anatomy and Histology, collaboration with the Department of Pathology, Bangladesh Agricultural University, Bangladesh. Bursa of Fabricious, spleen and thymus of 21-days-old Gumboro-infected and non-infected broilers of same age (control) were routinely processed and stained by hematoxylin and eosin to examine the distribution of lymphocytes in the major lymphatic organs as well as quantified the number of lymphocytes under high power magnification field and compared with those of control. The number of lymphocytes in bursa of Fabricious, spleen and thymus of Gumboro-infected broilers were 27.20 ± 1.53, 66.50 ± 2.70 and 79.30 ± 3.92 whereas 121 ± 3.82, 89.90 ± 2.09 and 106.30 ± 4.07 were in non-infected control respectively. The numbers of lymphocytes were significantly (p < 0.05) lower in all lymphatic organs of Gumboro-infected broilers than those of non-infected control. The significant numbers of lymphocytes decrease in spleen and thymus suggest that IBVD not only destroy lymphocytes in bursa of Fabricious, but also in spleen and thymus and thus may severely suppress the immune response of IBVD affected broilers.

La enfermedad de Gumboro es causada por el virus de la bursitis infecciosa (VBI), que destruye rápidamente los linfocitos B inmaduros de la bolsa de Fabricio, y causa supresión inmune y la elevada mortalidad en las granjas comerciales de pollos de engorde en Bangladesh. Para investigar el posible efecto del VBI en los linfocitos y su distribución en los órganos linfoides principales, la bolsa de Fabricio, incluyendo el bazo y el timo de pollos de engorde naturalmente infectados con Gumboro, se realizó una investigación en el Departamento de Anatomía e Histología, y el Departamento de Patología, Universidad Agrícola de Bangladesh, Bangladesh. Tanto la bolsa de Fabricio, bazo y el timo de pollos de engorde con 21 días de edad infectados con Gumboro y no infectados de la misma edad (control) se procesaron de forma rutinaria y se tiñeron con H & E para examinar la distribución de los linfocitos en los órganos linfáticos principales, así cuantificar el número de linfocitos bajo campo de alta magnificación y compararlos con los de control. El número de linfocitos en la bolsa de Fabricio, bazo y timo de pollos infectados con Gumboro fue 27,20 ± 1,53, 66,50 ± 2,70 y 79,30 ± 3,92, respectivamente, mientras que en los controles no infectados fue 121 ± 3,82, 89,90 ± 2,09 y 106,30 ± 4,07 respectivamente. El número de linfocitos fue significativamente (p < 0,05) más bajo en todos los órganos linfáticos de pollos de engorde infectados con Gumboro que los no infectados. La disminuición significativa de linfocitos en el bazo y timo, sugiere que el VBI no sólo destruye linfocitos en la bolsa de Fabricio, sino también en el bazo y el timo y, por tanto, puede suprimir severamente la respuesta inmune de pollos de engorde afectados por VBI.

Histological aspects of autologous transplantation of different fragments of the spleen in rats / Aspectos histológicos do transplante autólogo de diferentes fragmentos de baço em ratos

PURPOSE: To evaluate macro and microscopically the evolution of autotransplants of fragments of spleen different fragments in the greater omentum, after eight weeks of observation. METHODS: Twenty rats Wistar were used, males and adults, submitted to total splenectomy and divided in two groups. The group I - ten animals with implant of spleen fragment (25% weight of spleen) in the omentum; and group II - ten animals with implant of spleen fragment (30% weight of spleen) in the omentum. It was analyzed macro and microscopically the evolution of the implant. RESULTS: It was observed adherences to the adjacent tissues and vascularization in all of the fragments transplanted. The group I and II presented white pulp with follicular formations and lymphoid tissue preserved, and the red pulp in cordon aspect. The group II presented white pulp more disorganized and red pulp hemorrhagic. The active macrophages were observed in the group I and II. CONCLUSION: The splenic autotransplantation of the group I showed better regeneration.

OBJETIVO: Avaliar macro e microscopicamente a evolução do autotransplante de diferentes fragmentos de baço no omento maior, após oito semanas de observação. MÉTODOS: Foram utilizados 20 ratos Wistar, machos e adultos, submetidos a esplenectomia total e distribuídos em dois grupos. O grupo I - dez animais com implante de fragmento com 25% do peso do baço no omento e o grupo II - dez animais com implante de fragmento com 30% do peso do baço no omento. Foram observados macro e microscopicamente a evolução dos implantes. RESULTADOS: Foi observada no fragmento transplantado aderência aos tecidos adjacentes e vascularização preservada. Os grupos I e II apresentaram polpa branca e vascularização preservada, polpa branca com formação folicular e tecido linfóide preservado, e a polpa vermelha com aspecto cordonal. O grupo II apresentou polpa branca mais desorganizada e polpa vermelha hemorrágica. Os macrófagos ativos foram observados nos grupos I e II. CONCLUSÃO: O autotransplante esplênico do grupo I mostrou melhor regeneração.

Apoptosis induced in vivo by new type gosling viral enteritis virus

In this study, apoptosis was induced by new type gosling viral enteritis virus (NGVEV) in experimentally infected goslings is reported in detail for the first time. After 3-day-old goslings were orally inoculated with a NGVEV-CN strain suspension, the time course of NGVEV effects on apoptotic morphological changes of the internal tissues was evaluated. These changes were observed by histological analysis with light microscopy and ultrastructural analysis with transmission electron microscopy. DNA fragmentation was assessed with a terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay and DNA ladder analysis. A series of characteristic apoptotic morphological changes including chromatin condensation and margination, cytoplasmic shrinkage, plasma membrane blebbing, and formation of apoptotic bodies were noted. Apoptosis was readily observed in the lymphoid and gastrointestinal organs, and sporadically occurred in other organs after 3 days post-infection (PI). The presence and quantity of TUNEL-positive cells increased with infection time until 9 days PI. DNA extracted from the NGVEV-infected gosling cells displayed characteristic 180~200 bp ladders. Apoptotic cells were ubiquitously distributed, especially among lymphocytes, macrophages, monocytes, and epithelial and intestinal cells. Necrosis was subsequently detected during the late NGVEV-infection phase, which was characterized by cell swelling, plasma membrane collapse, and rapidly lysis. Our results suggested that apoptosis may play an important role in the pathogenesis of NGVE disease.

Avaliação imunológica nas pregas vestibulares de pacientes autopsiados com a Síndrome da Imunodeficiência Adquirida / Immunological evaluation of vestibular folds in autopsies of patients with the Acquired Immunodeficiency Syndrome

Em pacientes com Síndrome da Imunodeficiência Adquirida há uma diminuição das células envolvidas na resposta imune, o que influencia na população celular dos folículos linfóides encontrados nas pregas vestibulares, favorecendo o aparecimento de infecções nas vias aéreas destes pacientes. Estas infecções são a principal causa de mortalidade e morbidade nestes pacientes. OBJETIVO: Caracterizar a população de células nos folículos linfóides localizados nas pregas vestibulares de adultos autopsiados com Síndrome da Imunodeficiência Adquirida, com e sem infecções respiratórias associadas. MATERIAIS E MÉTODOS: Foi realizado um estudo retrospectivo transversal em 64 laringes de adultos coletadas na rotina das autopsias. Para a imunohistoquímica foram utilizados os anticorpos: Anti-B cells, Anti-CD3, Anti-CD68 e Anti-follicular dendritic cells. RESULTADOS: 46 (71,87 por cento) dos pacientes estudados tinham diagnóstico de Síndrome da Imunodeficiência Adquirida. Nestes pacientes, a celularidade dos folículos linfóides foi estatisticamente menor em relação ao grupo controle em todos os fenótipos estudados. Nos pacientes imunodeprimidos com infecção respiratória associada, o número de células estava diminuído, sendo significante no caso dos linfócitos T (p=0,024). CONCLUSÃO: Em nosso estudo demonstramos que os folículos linfóides das pregas vestibulares são afetados pela infecção viral e representam com fidedignidade o estado imunológico de imunodepressão destes pacientes.

Immune response cells are decreased in patients with the Acquired Immunodeficiency Syndrome. This alters the cell population in vestibular fold lymphoid follicles, leading to respiratory infections in these patients. Such infections are the main cause of mortality and morbidity in these patients. AIM: to characterize lymphoid follicle cell populations in the vestibular folds of adults with the Acquired Immunodeficiency Syndrome and associated or not respiratory infection. MATERIALS AND METHODS: A retrospective study was made of 64 adult larynges harvested during routine autopsies. Anti-B cell, Anti-CD3, Anti-CD68 and Anti-follicular dendritic cell antibodies were used for immunological testing. RESULTS: 46 (71.87 percent) of the sample patients had the Acquired Immunodeficiency Syndrome. In these patients, lymphoid follicle cellularity was lower compared to the control group. The cell number was decreased in patients with the Acquired Immunodefficiency Syndrome and associated respiratory tract infection. CONCLUSION: We demonstrated in this study that vestibular fold lymphoid follicles were affected by viral infections, and may be considered as a reliable marker of immunodepression in these patients.

Roles of Embryonic and Adult Lymphoid Tissue Inducer Cells in Primary and Secondary Lymphoid Tissues

The nomenclature "embryonic lymphoid tissue inducer (LTi) cell" reflects the fundamental role of the cell in secondary lymphoid tissue organization. In addition, it is equally important in primary lymphoid tissue development as it regulates central tolerance to self-antigens in the thymus. An adult LTi cell constitutively expresses two sets of tumor necrosis factor (TNF) family members, whereas its embryonic counterpart expresses only one. The first set is lymphotoxin (LT)alpha, LTbeta, and TNFalpha, which are essential for the secondary lymphoid organogenesis during embryogenesis and for maintaining an organized secondary lymphoid structure during adulthood. The second set is OX40- and CD30-ligands, which are critical for memory T cell generation. Adult LTi cells regulate adaptive immune responses by providing LTbetaR signals to stromal cells to maintain secondary lymphoid tissue structure, and determine adaptive immune responses by providing OX40 and CD30 survival signals to activated T cells in memory T cell generation. Along with the consideration of the roles of embryonic LTi cells in primary and secondary lymphoid tissues, this review highlights the roles of adult LTi cells in secondary lymphoid tissue function.

Expansion of a subset of TCR gamma/delta human lymphocytes from various lymphoid organs cultured with recombinant IL-2

1. TCR1 cells are a minor component of CD3+ lymphocytes which bear the gamma/delta T-cell receptor. There are limited data concerning the activation of TCR1 cells or TCR1 cell subsets in human lymphoid organs. We analyzed a subset of TCR1 cells (delta TCS1+) in peripheral blood (PBL), spleen (SPL), lymph nodes (LN), bone marrow (BM), and thymus (THY) after activation with IL-2. Lymphoid cells from these organs were cultured with 1500 U/ml IL-2 for 14 days and analyzed at periodic intervals for delta TCS1+ cells. 2. We found increased numbers of delta TCS1+ cells in 6- and 14-day cultures from SPL (20.8 +/- 11.8 per cent positive cells after 14 days of culture), LN, BM and THY but not in peripheral blood (1.8 +/- 0.9 per cent ). These delta TCS1+ cells coexpressed CD2, CD3, CD8 and CD56, but were negative for TCR alpha/beta and CD4. We also detected an expansion of TCR1+ cells in IL-2-stimulated PBL employing the pan-gamma/delta marker TCR delta 1; however, in contrast to solid organs, these TCR1+ cells were delta TCS1 negative. 3. Sorting experiments demonstrated directly that delta TCS1 cells from spleen cultures mediate high cytotoxic activity against K562 cell targets (39.4 per cent median specific cytotoxicity) and low activity against Daudi (9.6 per cent ), COLO (2.7 per cent ) and an antibody-sensitized human B-cell line (17 per cent ). 4. These results show expansion and cytotoxic activation by IL-2 of a subset of human TCR1 cells in solid lymphoid organs