Pathogenesis of digestive tract lesions in duck plague.

White Pekin ducklings were inoculated orally with duck plague virus. Tissues from the digestive tract were collected daily after inoculation and examined by light, electron and fluorescent microscopy. There were necrosis and degeneration of stratified squamous epithelium of the esophagus and cloaca, epithelium of intestinal crypt and esophageal submucosal glands, macrophages in the lamina propria, and submucosal fibrocytes and lymphocytes. Submucosal hemorrhages occurred after degeneration and necrosis of lymphocytes, macrophages, fibrocytes and epithelial cells. Viral antigens were detected in all these cells by use of fluorescein-labeled antibodies. With the electron microscope, nucleocapsids were seen in the nuclei, budding through the inner nuclear membrane; enveloped virions were present in cytoplasmic vacuoles of macrophages, epithelial cells and fibrocytes. In lymphocytes, nucleocapsids were also in the nuclei, but karyorrhexis and cytolysis occurred before viral maturation was completed.     

Developmental changes in cell proliferation and apoptosis in the normal duck bursa of Fabricius

The aim of this work was to investigate developmental changes in cell proliferation and apoptosis in normal duck bursa of Fabricius using flow cytometry and immunohistochemistry. Studies were carried out on Tianfu ducks on days 24 and 27 of embryogenesis (E24 and E27) along with days 20, 70, and 200 of postnatal development (P20, P70, and P200). Results showed that the percentage of G₀/G₁ bursa cells significantly increased between E24 and P200 while the percentage of cells in the S phase or G₂ + M phase as well as the proliferating index obviously decreased during the same period. Proliferation cell nuclear antigen was detected in lymphocyte and interfollicular epithelium. The proliferative lymphocyte density tended to decrease from E24 to P200. Apoptotic bodies in macrophages, free apoptotic bodies, or nuclei with condensed chromatin in lymphocytes in follicles were identified by transferase-mediated dUTP nick-end labeling. Both flow cytometry and microscopic analysis reveal that the proportion of apoptotic cells and apoptotic lymphocyte density increased from E24 to P20, fell on P70, then rose again on P200. Our foundings demonstrate that cell proliferation decreases and apoptosis increases with age. These changes may account for duck bursa development and involution.     

Lymphocytic depletion of bursa of Fabricius and thymus in chickens inoculated with Escherichia coli

Specific-pathogen-free 10-week-old chickens were inoculated via the air sac with Escherichia coli and showed lymphocytic depletion of bursa of Fabricius and thymus. In experiment I, chickens were necropsied at 12 and 24 hours, 2, 3, and 5 days after inoculation. At 12 hours after inoculation there was lymphocytic depletion in the medulla of lymphoid follicles of the bursa. At 24 hours after inoculation there was lymphocytic depletion also in the cortex of follicles and edema in interfollicular interstitium and follicular medulla. At 2 and 3 days after inoculation there were more marked lymphocytic depletion in medulla and cortex, and fibrosis in interfollicular interstitium. Partial repopulation of follicles with lymphocytes was seen at 5 days after inoculation. In the thymus, lymphocytic depletion occurred in the cortex. At 12 hours after inoculation, lymphocytic necrosis increased in number more than that of control chickens. The width of the cortex and medulla decreased. At 24 hours after inoculation, lymphocytic necrosis increased further. At 2 to 5 days after inoculation, the boundary between the cortex and medulla of lobules was obscure and cellular elements of the cortex and medulla were mingled. In experiment II, chickens were necropsied as in experiment I and also at 8 and 14 days after inoculation. The relative weights of the bursa and thymus reduced rapidly to minimal relative weights at 8 days after inoculation. At 14 days after inoculation, both bursa and thymus had normal relative weights and histological structures. These findings indicate that E. coli infection may induce transient lymphocytic depletion of lymphoid tissues in the chicken.     

神经肽Y及其Y1受体阳性细胞在鸭腔上囊中的分布及发育变化(英文)

神经肽Y及其Y1受体在神经-免疫-网路中发挥着重要作用。二者在许多脊椎动物胸腺和脾脏中的表达已有研究,但它们在腔上囊中的表达及发育变化特征还未见报道。本试验应用免疫组化技术研究神经肽Y及其Y1受体阳性细胞在鸭腔上囊胚胎及胚后发育中的分布及变化特征。结果显示,在鸭腔上囊中神经肽Y及其Y1受体分别最早表达于26和22d胚龄。神经肽Y阳性细胞分布于黏膜上皮、滤泡、肌层和小动脉平滑肌。Y1受体阳性细胞分布于黏膜上皮、滤泡淋巴细胞。各部位神经肽Y及其Y1受体阳性细胞数量表现出明显增龄变化特征。结果说明鸭腔上囊中存在神经肽Y及其Y1受体,二者可能存在的相互作用主要表现在胚后发育阶段,这与B淋巴细胞的发育与分化以及腔上囊的退化密切相关。     

B cell differentiation in the bursa of Fabricius and spleen of embryos and chicks immediately after hatching

Flow cytometric analysis and immunohistochemical observation were used to qualitatively and quantitatively clarify the nature of B cell differentiation in the bursa of Fabricius of chick embryos and to determine the timing of antibody class switching in chicken spleens based on positivity of IgM and IgG on and in the cells. In the bursa, the sIgM‐positive cell population formed from the 12^th to 15^th day of embryogenesis. The proportion of sIgM‐high expressing (sIgM^high) cells was lower among bursacytes than splenocytes of hatched chicks, suggesting that the sIgM^high bursacytes are to be released to peripheral sites. The proportion of sIgM^high cells was higher at 0 days old than at any other examined stage of development. Colonization of the spleen by B cells occurred between the 18^th day of embryogenesis and 0 days old. Antibody class switching was thought to start in the spleen between 1 and 2 weeks of age, because IgG‐positive cells were present in the spleen of 2‐week‐old chicks, but not 0‐day‐old or 1‐week‐old chicks.     

Cryptosporidiosis of the bursa of Fabricius of chickens.

Light-microscope and electron-microscope studies of a coccidial organism found in the bursa of Fabricius from 3 chickens clearly established the parasite as belonging to the family Cryptosporiidae. Hyperplasia and heterophil infiltration were associated with the presence of organisms attached to the microvillus border of epithelial cells lining the plicae of the bursa of Fabricius. Although there were no clinical signs or gross lesions common to the 3 cases described, all had similar histologic lesions in the epithelium lining the bursa of Fabricius.     

5种弥散神经内分泌细胞在鸭腔上囊中的表达特征

应用免疫组化技术并结合图像分析软件研究了胃泌素、β-内啡肽、胰高血糖素、5-羟色胺、生长押素在鸭腔上囊中的表达特征.结果显示鸭腔上囊小结相关上皮细胞呈胃泌素强阳性反应;滤泡间粘膜上皮呈β-内啡肽中强度阳性反应;淋巴滤泡皮质部有少量的β-内啡肽、胃泌素、5-羟色胺阳性细胞,呈中、强度免疫反应;淋巴滤泡髓质有胃泌素强阳性细胞;生长抑素和胰高血糖素均呈阴性反应.结果说明,鸭腔上囊中存在β-内啡肤、胃泌素、5-羟色胺弥散神经内分泌细胞,它们在淋巴滤泡皮质部的表达特征有利于其通过内分泌和旁分泌方式调节B细胞的发育.     

Monoclonal antibodies as probes for defining cellular subsets in the bone marrow, thymus, bursa of fabricius, and spleen of the chicken

Using immunohistochemistry, the distribution and characteristics of cells detected by the newly developed monoclonals HIS-CI (B lymphocytes), HIS-C7 (leucocytes), HIS-C12 (IgM), CVI-ChIgM-59.7 (IgM), CVI-ChIgG-47.3 (IgG), and CVI-ChIgA-46.5 (IgA) are described in bone marrow, thymus, bursa of Fabricius, and spleen of chickens of different ages. Furthermore, quantification of cells positive with the described monoclonal antibodies was performed on cytocentrifuge preparations. The specificities of the monoclonal antibodies are discussed.     

Developmental process of Cryptosporidium in the intestine and bursa of Fabricius of chickens.

The developmental process of a Cryptosporidium isolated in Japan in the chicken intestine was investigated by scanning (SEM) and transmission electron microscopies (TEM). The parasites were detected in the ileum, cecum, colon, cloaca and bursa of Fabricius (BF). The intensity of infection tended to peak later in the BF than ileum. Trophozoites and schizonts were detected in all the portions of intestine, and were dominant in the developmental stages. Although macrogamonts were the secondary dominant stage, they were absent in the ileum and cecum at 60 hr postinoculation (PI). A few microgamonts were detected in the ileum at 36 hr PI and in the BF on day 19 PI. Oocysts were observed in the ileum at 48 hr PI and in the BF on day 19 PI.     

Studies on the pathogenesis of Escherichia coli in the bursa of Fabricius (cloacal bursa) of the turkey.

Turkey poults were inoculated with avirulent or virulent strains of Escherichia coli by direct application to anal lips and were killed at postinoculation hours (PIH) 0.1, 2, 5, 10, 24, 48, 72, and 96. Bursae of Fabricius (cloacal bursae) were collected, cultured, and examined by light, fluorescent, and electron microscopy. The virulent strain of E coli was not recovered from the bursae after PIH 24, although the avirulent strain was recovered up to PIH 96. The E coli strains neither localized at nor associated with the bursal fold epithelium, passed through the follicular pad epithelium, nor caused cytopathologic changes in the lymphoid follicle. A mild catarrhal bursitis was observed at PIH 48 with the avirulent strain of E coli.     

雏鸭腔上囊的生长及组织发育

通过对1～49日龄雏鸭腔上囊绝对质量和生长指数测定以及组织学观察,探讨雏鸭腔上囊生长及组织发育规律。结果:随日龄增长,腔上囊绝对质量逐渐增高;腔上囊生长指数21日龄达最高;黏膜大皱褶高、宽度、淋巴滤泡面积、皮质宽度均不断增加;小结相关上皮向腔面形成突起,并不断增高增宽。结果表明,雏鸭腔上囊1～14日龄生长较为缓慢,14～35日龄生长较快,35～49日龄发育基本趋于稳定,其中21～28日龄是雏鸭腔上囊生长发育的高峰时期,28日龄时,雏鸭腔上囊组织结构基本发育成熟。     

Histochemical and histological evaluations of the effects of high incubation temperature on embryonic development of thymus and bursa of Fabricius in broiler chickens

1.?The effects of experimentally induced heat-stress on the embryonic development of bursa of Fabricius and thymus of the chicken were investigated by means of histological and enzyme histochemical methods.

2.?In the experiments, 250 fertile eggs of the Ross 308 broiler strain were divided into two groups. The control eggs were maintained under optimal conditions (37?8°C and 65 ± 2% relative humidity, RH) during the whole incubation period. Heat stressed eggs were maintained under normal conditions (37?8°C and 65 ± 2% RH) until the 10th d of incubation and then exposed continuously (24 h per d) to high temperature (38?8°C and 65 ± 2% RH). Blood and tissue samples were taken from 10 animals of each group at d 13, 15, 18 and 21 of incubation and at d 2, 4 and 7 post-hatch. Tissue samples were processed for enzyme histochemical methods in addition to routine histological techniques.

3.?The results revealed that egg temperatures were higher than incubator air temperature. Long-term heat-stress (40?1–40?6°C egg temperature) retarded development of thymus and bursa of Fabricius. Peripheral blood ACP-ase and ANAE-positive lymphocyte levels of heat-stressed animals were lower than in the controls.

4.?These results give some morphological evidence for immunosuppression induced by high temperature exposure during the embryonic development. Temperature distribution and air circulation in incubator should be questioned in the case of lower broiler flock immunity.