RESUMEN
Light and electron microscopical investigations revealed that the lymphoid structure of the chicken Harderian gland is organized in different histological frameworks. In the head the surface epithelium of the central canal can be classified as a lymphoepithelial tissue which covers the dense lymphoid substance. It consists of small and medium-sized lymphocytes, dendritic-like cells, and occasional macrophages. High endothelial venules are associated with intense lymphocyte migration and homing that gives circumstantial evidence for a T-dependent region, as found in a secondary lymphoid organ. The B-dependent germinal centers are also common structural units of the head region's lymphoid substance. The body of the gland is loaded with plasma cells of different maturation stages. They immigrate into the epithelium of the central canal and produce IgM and IgA. Only a few scattered IgG producing plasma cells can be found in the gland of Harder. This plasmocytic region accounts for the immunosurveillance on the conjunctiva and in the upper respiratory tract through antibody production against bacterial or parasitic infections. In both the head and body regions of the gland, anti-B-L (anti-Ia) antibody recognized scattered elongated cells which might represent dendritic cells. The immunological relationship between the two histologically different parts of the Harderian gland is unknown, but we speculate that the dense lymphoid tissue with high endothelial venule receives the blood-borne, immunologically mature, but uncommitted B cells. By the influence of local antigen stimulus, these B cells transform to plasma cells which gradually appear in the body of the gland. The lymphoid structures of the head and the body fulfill the function of secondary and tertiary lymphoid organs, respectively.
Asunto(s)
Glándula de Harder/anatomía & histología , Glándula de Harder/inmunología , Tejido Linfoide/anatomía & histología , Tejido Linfoide/inmunología , Animales , Movimiento Celular , Pollos , Células Dendríticas/citología , Epitelio/anatomía & histología , Epitelio/ultraestructura , Glándula de Harder/ultraestructura , Antígenos de Histocompatibilidad Clase II/inmunología , Inmunoglobulina G/metabolismo , Linfocitos/citología , Tejido Linfoide/ultraestructura , Macrófagos/citología , Células Plasmáticas/citología , Células Plasmáticas/metabolismo , Vénulas/anatomía & histologíaRESUMEN
Fertile eggs were dipped on the fifth day of incubation into varying concentrations of allylestriol (AE), a synthetic progesterone, and testosterone propionate (TP). Concentrations of AE higher than 0.1% inhibited hatchability. The AE inhibited the differentiation of the bursal mesenchyme and follicular development and subsequently resulted in bursectomy. The AE caused bursectomy in 40-50 times lower concentrations than did TP. An unusual lymphocyte accumulation occurred around the postcapillary venules in the bursal mesenchyme of AE-treated birds. This observation suggested that inhibition of mesenchyme differentiation may lead to a modification in bursal function. The AE modification of bursal development was compared to those produced by TP. We demonstrated that AE caused immunosuppression of the B-cell system.
Asunto(s)
Bolsa de Fabricio/efectos de los fármacos , Progesterona/análogos & derivados , Animales , Linfocitos B/citología , Linfocitos B/efectos de los fármacos , Linfocitos B/inmunología , Bolsa de Fabricio/embriología , Bolsa de Fabricio/inmunología , Diferenciación Celular/efectos de los fármacos , Embrión de Pollo , Pollos , Progesterona/farmacologíaRESUMEN
The potentiating effect of levamisole (L) on the phytohemagglutinin (PHA) induced hypersensitivity skin reaction in the chicken's wattle was studied. The L increased the number of heterophils and basophils 10 and 6 times, respectively. The number of mononuclear phagocytic cells in the PHA skin reaction was unaltered. These results contrast slightly with those of mammals.
Asunto(s)
Basófilos/inmunología , Pollos/inmunología , Cresta y Barbas/efectos de los fármacos , Hipersensibilidad a las Drogas/veterinaria , Hipersensibilidad Tardía/veterinaria , Levamisol/farmacología , Animales , Cresta y Barbas/inmunología , Femenino , Leucocitos/inmunología , Masculino , Fagocitos/inmunología , Fitohemaglutininas/farmacología , Enfermedades de las Aves de Corral/inducido químicamenteRESUMEN
A single large dose (200 mg/kg) of cyclophosphamide (Cy) caused thymic involution. Thymic cortex was almost depleted of lymphocytes while medullary thymocytes were not affected. This resulted in thymic inversion on day 4. During the period of involution the cortex was invaded by positive acid phosphatase granules containing macrophages. Later the cytoplasms of these macrophages were loaded with lipid droplets and residual materials. Extensive vacuolization of the cytoplasms of epithelial and special cells were revealed. Regeneration began on day 4. Repopulating cells appeared primarily in subcapsular region. Regeneration was complete by day 11 as examined by morphological technics. While FCS dependent rosette formation capacity remained below the control level even on day 16.
Asunto(s)
Ciclofosfamida/toxicidad , Timo/efectos de los fármacos , Animales , Autorradiografía , Gránulos Citoplasmáticos/ultraestructura , Femenino , Linfocitos/efectos de los fármacos , Macrófagos/efectos de los fármacos , Macrófagos/ultraestructura , Microscopía Electrónica , Mitosis , Sistema Mononuclear Fagocítico/ultraestructura , Ratas , Ratas Endogámicas , Formación de Roseta , Timo/patología , Timo/ultraestructuraRESUMEN
A single large dose (200 mg) of cyclophosphamide (Cy) given to adult rats caused a drastic depletion of lymphocytes occurring earlier in the B dependent compartment than in the T dependent one of the lymph node cortex. The drug had a somewhat facilitating effect on the early differentiation of plasma cells (between 12 and 24 h) which later were also depleted. By Cy administration two types of macrophage were distinguished morphologically and topographically in the lymph nodes. Cy effect the endothelial cells lining the blood vessels and lymph sinuses. From day 4 to 7 Cy caused a constant flooding of red blood cells into the lymph node sinuses like in the normal rat haemolymph gland. Regeneration of the mesenteric lymph nodes occurred by a repopulation of lymphoid cells and a proliferation of other cell types. Repopulation of the B dependent compartment lagged behind that of the T dependent compartment. Regeneration of endothelial cells seemed to be one of the factors facilitating the repopulation of lymphoid cells. The distribution of T and B dependent cells in different compartments of the rat lymph node and activation of mononuclear phagocytes in Cy treated rat lymph node are discussed.
Asunto(s)
Ciclofosfamida/toxicidad , Ganglios Linfáticos/efectos de los fármacos , Animales , Autorradiografía , Vasos Sanguíneos/efectos de los fármacos , Endotelio/efectos de los fármacos , Endotelio/ultraestructura , Ganglios Linfáticos/ultraestructura , Linfocitos/efectos de los fármacos , Macrófagos/efectos de los fármacos , Macrófagos/ultraestructura , Mesenterio , Células Plasmáticas/efectos de los fármacos , Ratas , Ratas EndogámicasRESUMEN
With the help of electron microscopic investigations the morphological and functional connection of the epithelialial and lymphoid elements was examined in the lymphoepithelial organs (thymus, bursa of Fabricius, tonsils, Peyer's patches, gland of Harder). In all these organs special receptor cells were demonstrated, which may play a role in the uptake and transfer of the antigen. In the cytoplasm they all contain characteristic flattened vacuoles, with walls similar to the structure of the cell membrane. Formation of these bodies is identified with the striated bodies of micropinocytosis vermiformis and it was observed that the endocytosis start with a disintegration of the cell membrane which enters with the absorbed antigen in characteristic form into the cytoplasm of the epithel cell and induces the process of cellular immunity. Besides the function of lacrimal secretion the Harder's gland, as a lymphoepithelial organ is full of plasma cells, which constitutes the main lymphoid elements of this organ.
Asunto(s)
Tejido Linfoide/ultraestructura , Animales , Bolsa de Fabricio/ultraestructura , Pollos , Epitelio/ultraestructura , Glándula de Harder/ultraestructura , Humanos , Tejido Linfoide/inmunología , Tonsila Palatina/ultraestructura , Ganglios Linfáticos Agregados/ultraestructura , Conejos , Timo/ultraestructuraRESUMEN
The chicken's gland of Harder is characterized by a lymphoepithelial structure and an abundance of plasma cells in the epithelial interstices. Using 3HTdR labelling method, it is revealed that a considerable number of lymphoid cells in the gland of Harder originates from the bursa of Fabricius. However, surgical bursectomy at hatching does not influence the development of the lymphoepithelial structure in the gland of Harder. Testosterone propionate treatment of 3-day-old embryos inhibits the bursal development but not that of the gland of Harder. These findings argue for the relative bursal independence of lymphoid development in the gland of Harder.
Asunto(s)
Glándula de Harder/citología , Aparato Lagrimal/citología , Tejido Linfoide/fisiología , Animales , Bolsa de Fabricio/fisiología , Embrión de Pollo , Pollos , Glándula de Harder/efectos de los fármacos , Técnica de Dilución de Radioisótopos , Testosterona/farmacología , Timidina/metabolismo , Timo/fisiologíaRESUMEN
The Harderian gland is an exocrine gland located in the orbit of the chicken. In the stroma of the folds, an extreme amount of plasma cells can be observed. Electron-microscopic observations revealed that the surface epithelium over the margin of the folds is joined up to deeper epithelial cells with processes rich in tonofibrils and the space among them is filled with plasma cells. The basement membrane separating the surface epithelium from the underlying connective tissue is lacking in these areas, therefore, plasma cells are in direct contact with epithelial cells. A fine network of reticular fibrils can be found inside the folds and reticulum cell-like elements with long processes are intercalated among the plasma cells. This morphology resembles that of the lymphoepithelial organs. Based on this similarity the lymphoepithelial character and a possible immunological function of the Harderian gland is supposed.