Strategic Localization of Toll‐like Receptor 4 in the Digestive Tract of Blunt Snout Bream (Megalobrama amblycephala)

This study was performed to determine the localization strategies of Toll‐like Receptor 4 (TLR4) in digestive tract (oesophagus, bulbodium, foregut, midgut and hindgut) of Blunt snout bream (Megalobrama amblycephala) using immunohistochemical staining method. TLR4 positive cells were observed throughout the digestive tract. In the oesophagus, some positive reactions in lamina propria were found around small blood vessels and there were also some positive cells within the stratified squamous epithelium. Lots of positive cells were observed in the muscular layer of the oesophagus. In bulbodium, foregut and hindgut, the expression of TLR4 was mainly restricted to the apical surface of epithelial cells located at the bottom of the mucosal folds and the mesenchymal cells in lamina propria. It was very interesting that epithelial cells in the midgut, but none in other parts, had many TLR4 positive cytoplasmic granular structures which were also periodic acid Schiff positive. These findings suggested that TLR4 was expressed in a compartmentalized manner in the Blunt snout bream (M. amblycephala) digestive tract and provided novel information about the in vivo localization of pattern recognition receptors.     

In situ characterization of mononuclear leukocytes in skin and digestive tract of persistently bovine viral diarrhea virus-infected clinically healthy calves and calves with mucosal disease

The phenotypic identity of mononuclear leukocytes in skin and digestive tract of bovine viral diarrhea virus (BVDV)-infected animals was examined using sensitive single and double labeling immunocytochemical techniques. Occurrence and distribution of B lymphocytes, T lymphocytes of either the helper (BoT4) or suppressor/cytotoxic (BoT8) subsets, and macrophages (M phi) were examined. No differences were found in the skin and digestive tract of persistently infected clinically healthy calves and uninfected controls, despite widespread virus-antigen presence in keratinocytes (stratum basale and stratum spinosum) of skin and upper digestive tract, in dermal/subepithelial macrophages (M phi), in gut-epithelial cells, and in lymphocytes and M phi/monocytes of blood and lymphoid tissues of the former group. M phi and Langerhans cells (LC) were the prevailing leukocyte types in the keratinized epithelia and subepithelial connective tissues, with occasional T lymphocytes (mostly intraepithelially located and of the BoT8 phenotype). No B cells were seen. Some infiltrating leukocytes also contained virus antigen. In animals succumbing to mucosal disease (MD), hyper- and parakeratotic changes, as well as necrotizing epithelial lesions, were accompanied by massive infiltration in dermis and epithelium of major histocompatibility complex (MHC) class II antigen positive cells (M phi and LC), some T lymphocytes (predominantly BoT8 positive cells), and, only rarely, B cells. M phi also predominated in lamina propria of the gastrointestinal tract. Findings suggest that M phi activation is an important aspect of MD pathogenesis. In contrast, the contention that T lymphocytes may play a major role could not be substantiated.     

野生黄鼬消化管组织结构的观察

通过组织学观察,探讨野生黄鼬消化管的组织结构特点.将8只野生黄鼬经乙醚麻醉后处死,解剖取食管、胃、小肠、大肠,制作石蜡切片,观察其组织结构.结果显示野生黄鼬食管的黏膜为复层扁平上皮,食管腺发达,肌层以骨骼肌为主.胃贲门部有发达的皱襞和贲门腺;胃底腺有大量的主细胞和壁细胞;胃大弯部的腺体以壁细胞为主,仅有少量主细胞;胃幽门部有发达的幽门腺和大量壁细胞.十二指肠黏膜层有小肠腺,内有潘氏细胞存在,黏膜下层含有十二指肠腺;空肠可见孤立淋巴小结、弥散淋巴组织及集合淋巴小结.结肠无皱襞和肠绒毛,大肠腺排列紧密,其中杯状细胞特别多;直肠固有膜内有发达的大肠腺.所以野生黄鼬消化管的特点是胃各部胃腺发达,壁细胞特别多.     

Comparative distribution of immunoglobulin-containing cells in stomach, intestine and associated lymph nodes of cattle

Immunoglobulin (Ig)-containing cells were investigated immunohistochemically in the stomach, intestine and associated lymph nodes of clinically normal calves, cows and fetuses to examine mucosal immune responses in the forestomach to rumen microbial flora. IgG-containing cells were observed in the mucosal propria of the forestomach of a 32 day-old, a 37 day-old, two 90 day-old calves, and of all 5 cases of cows. However, no IgA- and IgM-containing cells were observed. Further, no Ig-containing cells were detected in the associated lymph nodes of all calves and cows. Various numbers of Ig-containing cells, predominantly IgG, were observed in the mucosal propria of the abomasum, small intestine and cecum, and in the mesenteric lymph nodes of aged calves and all cows. No Ig-containing cells were observed in any tissues of fetuses. The results suggest that the development of mucosal immune responses in the forestomach may be incomplete as compared with that of the intestine.     

猪呼吸道淋巴组织发育的亚显微结构变化

应用组织学和电镜技术研究猪呼吸道发育过程中淋巴组织的变化。结果表明：扁桃体和咽部是呼吸道进入机体的第一个淋巴组织集中的部位，弥散淋巴组织在出生时就存在，淋巴小结不明显；20日龄时扁桃体中淋巴组织增生，淋巴小结清晰可见；120日龄淋巴小结数量增加，紧靠鳞状上皮密集排列，淋巴小结发育很好，并出现生发中心。扁桃体复层鳞状上皮中含有大量的上皮内淋巴细胞。气管叉是呼吸道进入机体的第二个淋巴组织集中的部位，出生时气管叉外膜中淋巴组织直接与气管支气管淋巴结相连，淋巴组织明显可见。20日龄时气管叉外膜中淋巴组织已分开，形成气管叉外膜密集的淋巴组织和气管支气管淋巴结两个部分。120日龄时气管叉处淋巴组织特别发达，黏膜上皮中上皮内淋巴细胞数量也显著增加。肺内气管和细支气管固有膜中均有较多的淋巴细胞，其中浆细胞数量增加，上皮中仍存在少量的上皮内淋巴细胞。本试验结果提示猪呼吸道是黏膜免疫较理想的诱导位点和效应位点，新生仔猪通过鼻腔免疫可提高呼吸道局部黏膜免疫力。     

Experimental infection of calves with bovine viral diarrhea virus genotype II (NY-93).

To ascertain the virulence of bovine viral diarrhea virus (BVDV) genotype II, isolate NY-93 was inoculated intranasally into 3 calves, 2 of which were treated with a synthetic glucocorticoid prior to and after virus inoculation. Anorexia, fever (up to 42 C), dyspnea, and hemorrhagic diarrhea developed 6 days after intranasal inoculation with BVDV NY-93. The condition of all calves deteriorated further until the end of the study on day 14 postinoculation. The most significant postmortem macroscopic changes in all calves were limited to the gastrointestinal tract and consisted of moderate to severe congestion of the mucosa with multifocal hemorrhages. Microscopic lesions found in the gastrointestinal tract were similar to those observed in mucosal disease, including degeneration and necrosis of crypt epithelium and necrosis of lymphoid tissue throughout the ileum, colon, and rectum. The basal stratum of the epithelium of tongue, esophagus, and rumen had scattered individual necrotic cells. Spleen and lymph nodes had lymphocytolysis and severe lymphoid depletion. Severe acute fibrinous bronchopneumonia was present in dexamethasone-treated calves. Abundant viral antigen was detected by immunohistochemistry in the squamous epithelium of tongue, esophagus, and forestomachs. BVDV antigen was prominent in cells of the media of small arteries and endothelial cells. The presence of infectious virus in tissues correlated with an absence of circulating neutralizing antibodies. These findings highlight the potential of BVDV genotype II to cause severe disease in normal and stressed cattle.     

秦岭细鳞鲑消化系统的形态学观察

运用大体解剖和常规组织学方法对秦岭细鳞鲑消化系统的组织形态进行了系统观察。结果表明,秦岭细鳞鲑的消化道由口咽腔、食道、胃和肠等4部分组成,除口咽腔外,管壁由内向外分为黏膜、黏膜下层、肌层和浆膜。口咽腔宽大,上颌、犁骨及腭骨等处布有细齿,黏膜衬以复层扁平上皮,间有较多的黏液细胞和少量的杯状细胞及味蕾;食管粗而短,黏膜向管腔突出形成多个纵行皱襞,上皮由复层扁平上皮逐渐向单层柱状过渡,上皮细胞间可见到数量较多的粘液细胞和杯状细胞,食管腺不发达;胃体积较大,呈“U”形,包括贲门部、胃体和幽门部,胃体部小凹及胃底腺结构明显,肌层发达;胃与肠相接处有63-65个幽门盲囊,肠道粗短而略微盘曲,黏膜上皮为单层柱状,未见明显的肠腺。以上结果显示,秦岭细鳞鲑消化道组织结构与其肉食性功能密切相关。肝小叶界限不清;双列肝细胞围绕中央静脉呈放射状走行,肝细胞个体大、呈多边形,核呈圆形或卵圆形,1-2个。胰脏大部分环绕前肠边缘、呈细长条索状,另可见分散于幽门盲囊及胃周围的弥散部分;其外分泌部为管泡状腺,腺细胞呈锥体形,胰岛结构明显。     

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.     

牦牛皱胃组织结构及黏膜免疫相关细胞研究

为揭示牦牛皱胃组织结构和黏膜免疫相关细胞的分布与数量变化的规律,采用组织化学法、图像分析法及透射电镜技术,对牦牛皱胃组织结构及上皮内淋巴细胞、浆细胞和肥大细胞变化进行了研究.结果表明:牦牛皱胃胃壁由黏膜层、黏膜下层、肌层和浆膜构成.皱胃幽门腺区胃小凹深度最深、腺体最长、肌层最厚;3个腺区肌层厚度、腺体长度之间差异极显著(P＜0.01);幽门腺区与胃底腺区、贲门腺区之间胃小凹差异极显著(P＜0.01),胃底腺区与贲门腺区之间差异不显著(P＞0.05).牦牛皱胃黏膜上皮内淋巴细胞数量和浆细胞数量,3个腺区之间差异不显著(P＞0.05);肥大细胞数量以胃底腺区最多,幽门腺区最少,两者之间差异极显著(P＜0.01),贲门腺区与胃底腺区和幽门腺区之间差异不显著(P＞0.05).皱胃各腺区固有层中均有大量的弥散淋巴细胞和孤立淋巴小结.电镜观察表明,胃小凹柱状上皮细胞排列紧密.幽门腺区固有层中有大量的黏液细胞,黏液细胞呈高柱状或锥体状,核位于基底部,在细胞顶端常聚集有较多的电子密度较高的颗粒.胃底腺区和贲门腺区有大量的壁细胞和主细胞.牦牛皱胃的组织结构和其他反刍动物基本相似,但各层有其明显特点.牦牛皱胃各腺区固有层中均有大量弥散淋巴细胞和孤立淋巴小结,使牦牛皱胃具有比其他反刍动物更强的黏膜免疫功能.     

Morphological and histochemical characterization of the mucosa of the digestive tract in Engraulis anchoita

The histomorphological aspects as well as the histochemical content and distribution of glycoproteins (GPs) in the mucosa of the digestive tract of the anchovy Engraulis anchoita were studied. The buccopharyngeal cavity is lined by a squamous stratified epithelium with mucous superficial cells; the oesophagus shows two zones, cranial with a squamous stratified epithelium with mucous superficial cells and caudal with a columnar secretory epithelium. Finally, the stomach presents both the cranial and pyloric portion lined with a simple columnar epithelium. Tubular branched glands, formed by a single type of glandular cell, located along the stomach, are more numerous in the cranial portion. The GPs were identified with (1) oxidizable vicinal diols; (2) sialic acids and some of their chain variants, C7 or C9; (3) sialic acid residues with O-acyl substitution at C7 or C8; (4) carboxyl groups and (5) sulphate groups. Histochemical tests showed that the buccopharyngeal cavity presented the largest amount of the different types of mucosubstances. Epithelial secretory cells were found in the oesophagus, which synthesized a large quantity of sialosulphoglycoproteins likely to be related to a protective role. The surface epithelium of the stomach synthesizes and secretes acid and neutral GPs, probably related to the movement of fluids and to the absorption of easily digested substrates, respectively. Although great differences exist between different species, in E. anchoita as in other fish species, the wall of the digestive tract is composed of the four layers classically described for vertebrates. The GPs secreted by the epithelial cells are suggested to be important for the protection and inhibition of microorganisms. In addition, they are involved in enzymatic digestion of food, absorptive functions and lubrication of the alimentary tract.     

Mast cells in the bovine lower respiratory tract: morphology, density and distribution

The lower respiratory tract of six 8-day-old calves and six adult cows was fixed in either isotonic formal-acetic-acid or neutral buffered formalin in order to study the morphology, density and distribution of mast cells. They were found at all levels of the tract with the highest density in the major bronchi. Tissues from cows had significantly more mast cells than those from calves. There were significantly more mast cells detected in calf airways fixed with isotonic formal-acetic-acid compared with those seen in the same tissues fixed with neutral buffered formalin. Regardless of the age and fixation, mast cells were located predominantly in the alveolar septa and in the lamina propria of airways. They were also commonly encountered within the mucosal epithelium of the trachea. Ultrastructurally, mast cells in bovine airways and lung contained two types of intracytoplasmic granules as described in other species.     

Ultrasonography of the teat canal in cows and sheep

When the isolated teat of a cow was examined with an 8.5 MHz linear array transducer in a vertical plane, the teat canal appeared as a thin, white line, bordered on each side by parallel, thick, grey-black bands. In a horizontal plane a comparable image was obtained. In a sheep, images of comparable quality were obtained with a 12 MHz transducer. Histological studies of the tissues whose removal led to the disappearance of this characteristic ultrasonographic appearance showed that it was associated with the stratified keratinised squamous epithelium with distinct papillae. The content of keratin in the stratum corneum was apparently responsible for the bright zone; the stratum lucidum was not visible, and the surrounding dark, less echoic area was associated with the stratum granulosum. Doppler echography in live animals confirmed this designation. The outer layers of the teat wall were more echogenic.     

Prevalence and pathogenicity of Cryptosporidium andersoni in one herd of beef cattle

Over a 35-week period from January to July 2002, a breed of Hereford beef cattle (H) and their hybrids were monitored. Five hundred and ninety-nine individual fecal samples from calves and 96 samples from their mothers were examined. First excretion of Cryptosporidium andersoni oocysts in calves was found in the 9th week after the start of calving (a calf 63-day old). The prevalence of C. andersoni in calves ranged from 11.1 to 92.9% depending on age. The mean prevalence in their mothers was found to be 43.8%. The size of oocysts was 8.48 +/- 0.78 x 6.41 +/- 0.59 microm. Infection intensity in calves ranged from 32 000 to 4 375 000 oocysts per gram (OPG) and in mothers from 78 000 to 2 552 000 OPG. Three cases of abomasal cryptosporidiosis slaughtered at the age of 81, 157 and 236 days were examined histologically and ultrastructurally [transmission electron microscopy (TEM) and scanning electron microscopy (SEM)]. Cryptosporidium infection of the abomasum was located in the upper half of the mucosal glands in the plicae spirales of the fundus, corpus and near the ostium omasoabomasicum. Cryptosporidia were not located in the glandular epithelium of the pars pylorica in the abomasum minimally 10 cm from pylorus. Histopathological changes in the site of cryptosporidial infection in the abomasum had a non-inflammatory character and included distinctive dilatation of infected parts of the glands with atrophy and metaplasia of the glandular epithelial cells, goblet cell activation and mucus hyperproduction. The TEM revealed a relatively small number of Cryptosporidium life cycle stages attached to glandular epithelial cells. In SEM the inner mucosal abomasal surface appeared swollen but was never infected by cryptosporidia.     

GHSR—1a在奶山羊胃肠道的分布与表达

试验采用免疫组织化学、Real—timePCR和Western blotting方法测定ghrelin的功能性受体GHSR-1a（Growth hormone seeretagogue receptor-1a,GHSR-1a）在奶山羊胃肠道的分布和表达。免疫组织化学结果显示,GHSR—1a免疫阳性细胞广泛分布于奶山羊胃肠道。在皱胃主要定位于黏膜层和肌层;瘤胃、网胃和瓣胃黏膜层及肌层中也可见GHSR-1a免疫阳性细胞;在小肠主要位于十二指肠、空肠和回肠的黏膜层、黏膜下层和肌层;在结肠、盲肠和直肠GHSR—1a免疫阳性细胞也有广泛分布;GHSR—1a主要表达于内在神经丛神经细胞、胃底腺上皮细胞、肠腺上皮细胞、复层鳞状上皮细胞、平滑肌细胞中。real—timePCR和Westernblotting结果显示,皱胃、十二指肠、空肠、回肠、盲肠、结肠和直肠GHSR—1a的表达水平相对较高,显著高于瘤胃、网胃和瓣胃的表达（P〈0．05）。结果表明,ghrelin可能通过GHsR-1a对奶山羊胃肠功能具有重要的调节作用。     

双峰驼胃组织学研究

双峰驼胃分为前胃和皱胃。前胃分２室，第一室有前、后２个腺囊区，第二室只有１个腺囊区。胃壁由粘膜、粘膜下层、肌层和浆膜构成。３个腺囊区的结构类似，均由界限明显的有腺部和无腺部组成，有腺部的腺体类似牛、羊的贲门腺。第一室非腺囊区、贲门、第二室食道沟及３个腺囊区的无腺部结构类似，其粘膜上皮为复层扁平上皮，表层细胞角化。皱胃分贲门腺、胃底腺和幽门腺３个腺体区，与牛、羊相应的腺体类似     

Gut-associated lymphoid tissue in the large intestine of calves. I. Distribution and histology

Gut-associated lymphoid tissue (GALT) in the large intestine was characterized in 12 calves (10 to 84 days old) obtained at necropsy (7, group A) or healthy animals (5, group B). Patches of mucosal lymphoid follicles were in all calves at ileocecal entrances (ICE), 23-42 cm distal to the ICE in the proximal loop of the ascending colon (proximal colon [PC] patch), and in the terminal rectum. PC patches varied from 8 to 30 cm in length. Solitary lymphoid follicles were found in the cecum of three calves, between the ileocecal entrances and the PC patch in four calves, adjacent to the PC patch in all calves, and in the ampulla recti. GALT occupied 7.8% of the large intestinal wall in animals of group A: 0.6% at the ileocecal entrance, 4.8% in the proximal colon, and 2.4% in the rectum. There were two different types of mucosal lymphoid follicles in group B: propria nodules with lymphoid follicles predominantly in the lamina propria, and lymphoglandular complexes with lymphoid follicles in the submucosa. In three 3-, 6-, and 7-day-old, germfree calves, distinct follicle-associated epithelium covered propria nodules and covering folds in depths of the lymphoglandular complexes; it was characterized by numerous intraepithelial cells and lack of goblet cells.     

Histological characteristics of induced acute peptic injury in equine gastric squamous epithelium.

The objective of the study reported here was to characterise the microscopic appearance of peptic-injured equine gastric squamous epithelium in relation to the duration of peptic injury. Erosions and ulcers were induced in equine gastric squamous epithelium using a feed deprivation protocol that results in prolonged increased gastric acidity. Specimens of normal gastric mucosa and mucosa with lesions created after 48 and 96 h of feed deprivation were compared for characteristics associated with angiogenesis and mucosal proliferation. Fifteen mature horses, 9 geldings and 6 mares, age 3-20 years, were divided into 3 groups. Group 1 (n = 5) had normal-appearing gastric squamous mucosal epithelium and had been killed due to problems unrelated to the gastrointestinal tract. Groups 2 (n = 5) and 3 (n = 5) had lesions induced in the gastric squamous epithelium by alternating 24 h periods of feed deprivation and ad libitum access to hay, for totals of 48 and 96 h feed deprivation, respectively. Following lethal injection of barbiturate, stomachs were removed and fixed by filling with 4-6 l 10% buffered formalin. Sections were made from lesions in the gastric squamous epithelium adjacent to the margo plicatus along the right side of the stomach/greater curvature and the lesser curvature. Measurements of total epithelial thickness, keratinised epithelium, nonkeratinised epithelium, epithelial projections, capillary extension into the epithelium and lamina propria thickness were made. The cross-sectional areas of arterial and venous vascular structures in the lamina propria at the lesions and their margins were measured using image analysis software. All horses, except one, in Group 2 developed erosions or ulcers in the gastric squamous epithelium after feed deprivation. There were several changes in the epithelium adjacent to erosions and ulcers, compared to normal epithelium, from horses in Groups 2 and 3: total epithelial thickness was significantly (P<0.05) greater, including both keratinised and nonkeratinised layers in most specimens; the length of epithelial projections and extent to which capillaries from the lamina propria extended toward the luminal surface, and the cross-sectional area of vascular structures (arterioles, capillaries, venules) in the lamina propria were significantly greater. Epithelial thickness of erosion beds was not significantly less than normal epithelium, although a greater proportion of the epithelium in erosions consisted of epithelial projections (Group 1, 23%; Group 2, 76%; Group 3, 72%). The cross-sectional area of vascular structures in the lamina propria beneath erosions was significantly greater than in normal mucosa only in Group 2 tissues, whereas in the lamina propria of ulcers it was significantly greater than in normal mucosa only in Group 3 tissues. The epithelial proliferation and increased vascular cross-sectional area in the lamina propria associated with peptic-induced gastric lesions are consistent with processes associated with the initiation of ulcer healing, and these changes temporally coincided with the initiation of peptic insult to the gastric squamous epithelium. These findings demonstrate that processes that promote ulcer healing begin soon after peptic injury and that they progress even with repeated peptic injury. Furthermore, our findings support observations that gastric ulcers often heal without medical intervention, and the theory that medications that reduce gastric acidity do not initiate healing, but rather facilitate ulcer healing by providing a microenvironment that is optimal for healing to proceed.     

Histological development and histochemical localization of enzymes in rumen and reticulum in bovine fetuses

Thirty Holstein fetuses from 100 to 251 d after conception were utilized to study prenatal anatomical development of the epithelium of the rumen and reticulum. Four calves at birth were included in the study for comparison. Tissue sections were frozen and stained to locate specific enzymes. At 100 d, the epithelial layer of the rumen was differentiated into a thin basal zone and a thickened superficial zone of undifferentiated cells. The basement membrane was straight, and in both zones cells were perpendicular to it. At 120 to 141 d, low, primary undulations were detected in the basal zone, basement membrane and underlying lamina propria. At 150 to 166 d, secondary undulations and incipient papillae began to resemble the papillae of mature mucosa. In rumen papillae of 192-d to 215-d fetuses, shallow furrows began to separate papillae apexes from the mass of epithelium. In fetuses 244 to 251 d, the papillae began to be a separate entity. At birth, the basal position of the papillae still remained fused. An incipient separation between the papillae was seen. Several dehydrogenase enzymes, including those associated with the Krebs cycle and reductase associated with energy transformation, were observed in both ruminal and reticular tissue. Alkaline phosphatase activity was localized in the stratum corneum and in blood vessels. Development of the honeycomb configuration of reticular epithelium was evident in the 100-d fetus and progressed rapidly with age.     

山羊咽扁桃体和咽鼓管扁桃体的组织结构观察

选取健康10月龄奶山羊10头,断头宰杀后取咽扁桃体和咽鼓管扁桃体,应用组织学光镜和电镜制片技术研究咽扁桃体和咽鼓管扁桃体的显微和亚显微组织结构.结果表明:山羊咽扁桃体和咽鼓管扁桃体的黏膜上皮主要由2～3层多边形上皮细胞组成,部分区域只有单层扁平细胞,相邻上皮细胞间空隙很大,上皮细胞表面有丰富的微绒毛.上皮细胞之间和黏膜上皮下方固有层内有大量淋巴细胞浸润.扁桃体的实质部分由数个次级淋巴小结和弥散淋巴组织构成,弥散淋巴组织中有大量分布的淋巴管和毛细血管后微静脉.此外,在紧贴黏膜上皮细胞下方的固有层和淋巴滤泡中可观察到少量的树突状细胞.结果提示山羊的咽扁桃体和咽鼓管扁桃体可作为鼻腔免疫的主要诱导位点和效应部位.