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1.
给２８日龄伊莎雏鸡人工接种新城疫病毒后，应用常规病理学检验、细胞化学和免疫组化技术对免疫器官的病理学变化作了研究。接毒１２ｈ，法氏囊滤泡的髓质、胸腺小叶的髓质、脾白髓、盲肠扁桃体的淋巴小结及弥散淋巴组织的部分淋巴细胞和网状细胞首先出现核浓缩、胞浆固缩等坏死变化。接毒１～３ｄ（潜伏期），骨髓、法氏囊滤泡、胸腺小叶、脾白髓和红髓、盲肠扁桃体粘膜层及弥散淋巴组织的淋巴细胞、巨噬细胞和网状细胞发生核浓缩、碎裂、胞浆固缩，强嗜酸性等坏死变化。接毒４～６ｄ死亡病例，这些免疫器官的淋巴组织散在呈蜂窝状空泡结构坏死灶（法氏囊为滤泡坏死），进一步崩解成无结构嗜酸性颗粒状物质。这些坏死变化可作为雏鸡新城疫诊断的根据。 相似文献
2.
应用生物素—亲和素(BA)法检测实验性传染性法氏囊病(IBD)鸡,在法氏囊、脾脏、盲肠扁桃体、胸腺、肝脏、肺脏、肾脏和心脏均检出了阳性细胞,并证明鸡传染性法氏囊病病毒(IBDV)最早定位于法氏囊滤泡髓质区的淋巴细胞胞浆内并进行复制,法氏囊滤泡的淋巴细胞是IBDV的主要靶细胞.接毒后ld,法氏囊滤泡就见有许多病毒;2～3d.病毒数量激增并达到高峰;4～5d,病毒数量维持较高水平;6～7d,病毒数量显著减少.本实验结果表明,BA法可以作为IBD的特异诊断方法,法氏囊可作为检测本病的首选器官,在法氏囊滤泡的髓质检出阳性淋巴细胞、阳性异染性白细胞和阳性巨噬细胞,或主要检出阳性巨噬细胞,均可作为本病的特异性诊断指标. 相似文献
3.
一岁龄犬淋巴器官的组织学和组织化学研究 总被引：1，自引：0，他引：1
对４只１岁龄犬的胸腺、淋巴结和脾进行了组织学和组织化学研究，并以酸性α－醋酸萘酯酶法显示Ｔ淋巴细胞的分布。结果表明：１岁龄犬胸腺发达；ＡＮＡＥ阳性淋巴细胞主要分布在胸腺小叶的皮质部；髓质内淋巴细胞数量较少，但分布有胸腺小体。淋巴结内分布有生发中心的次级淋巴小结，ＡＮＡＥ阳性反应的淋巴细胞分布在淋巴小结周围的套层及淋巴结的副皮质区。脾脏被膜和小梁发达，白髓以典型的脾小结和动脉周围淋巴鞘的形式散布在红 相似文献
4.
《畜牧兽医科技信息》2017,(9)
本实验通过对胸腺、法氏囊和脾脏的观察和检测来进行研究蛋氨酸缺乏对雏鸡机体免疫器官和免疫功能的影响,具体如下:对法氏囊的检测研究:通过组织学进行观察,雏鸡从21日龄开始法氏囊淋巴滤泡内的淋巴细胞发生变化,出现减少现象,并且雏鸡皮质变薄,髓质变宽现象也逐渐凸显出来。对胸腺检测研究:通过组织学观察研究,试验组胸腺小叶淋巴细胞较之于对照组显著减少,并且胸腺小叶结构变得模糊;对脾脏检测研究:试验组雏鸡脾脏的红髓和白髓淋巴细胞与对照组相比有明显较少现象并且其组织学结构发生紊乱。 相似文献
5.
鸡肾型传染性支气管炎病毒组织嗜性的研究 总被引：1，自引：0，他引：1
本研究用鸡肾型传染性支气管炎病毒 (肾型 IBV) C90 0 1株人工感染 14日龄 SPF鸡 ,于接种后定期采集病鸡的各组织器官制备成石蜡切片 ,用建立的检测石蜡切片中肾型 IB病毒的免疫酶组化染色技术 ,对人工感染肾型传染性支气管炎 (肾型 IB)鸡发病后病毒的组织器官亲嗜性和动态分布规律进行了研究。结果表明 ,肾型 IBV在胞浆内复制 ,主要亲嗜气管黏膜的上皮细胞和固有层腺体细胞、肺各级支气管上皮细胞以及肺房和呼吸性毛细管上皮细胞、气囊上皮细胞、肾和输尿管上皮细胞、消化道上皮和固有层腺体细胞、肝小叶间胆管上皮细胞、胰腺导管上皮细胞和腺泡上皮细胞、法氏囊淋巴滤泡髓质区淋巴细胞和网状细胞、胸腺小叶髓质区淋巴细胞和网状细胞、脾小体淋巴细胞、盲肠扁桃体弥散性淋巴组织的淋巴细胞以及心肌细胞 ,病毒出现的先后顺序为气管、肺脏、肾脏、输尿管 ,消化道、法氏囊、肝脏、胰脏、胸腺和气囊 ,盲肠扁桃体 ,脾脏 ,心肌。病毒在肾脏和输尿管持续 2 0天 ,气管为 13天 ,消化道和法氏囊为 11天 ,肝脏、胰脏和肺为 10天 ,胸腺为 6天 ,气囊为 5天 ,盲肠扁桃体、脾脏、心肌呈一过性感染 相似文献
6.
免疫器官中肾型鸡传染性支气管炎病毒的定位和动态分布 总被引：4，自引：0，他引：4
以鼠抗鸡肾型传染性支气管炎病毒（肾型IBV）的高免血清为一抗，辣根过氧化物酶（HRP）标记的羊抗鼠IgG为二抗，建立了检测石蜡切片肾型IBV抗原的间接酶标抗体染色技术。应用该技术对人工感染肾型IBV C9001株鸡免疫器官中的病毒进行了检测，结果胸腺和法氏囊是病毒主要侵害的免疫器官，脾脏，盲肠扁桃体仅呈一过性感染，哈氏腺未检测到，法氏囊从感染后2－12天，胸腺从感染后3－8天均检测到病毒抗原，阳性染色主要集中于法氏囊淋巴滤泡髓质区和胸腺小叶髓质区淋巴细胞和网状细胞胞浆内。 相似文献
7.
传染性法氏囊病病毒超强毒感染SPF鸡免疫器官中CD4+和CD8+T淋巴细胞动态分布 总被引：1，自引：0，他引：1
利用免疫组织化学染色对传染性法氏囊病病毒（IBDV）超强毒LX株感染SPF鸡免疫器官中CD4^ 和CD8^ T淋巴细胞的动态分布进行了研究。超强毒LX株接种2周龄SPF雏鸡，在其法氏囊、脾脏、胸腺、盲肠扁桃体、骨髓和哈氏腺中均可检出IBDV抗原的存在和CD4^ 与CD8^ T淋巴细胞的数量改变。在法氏囊中，CD4^ 淋巴细胞主要存在于淋巴滤泡间隙和滤泡皮质，而CD8^ T淋巴细胞则丰在于整个淋巴滤泡和滤泡间隙，并且CD8^ T淋巴细胞数量明显多于CD4^ T淋巴细胞，在接种后14d仍未见CD4^ 和CD8^ T淋巴细胞数量减少。脾脏中CD4^ T淋巴细胞主要存在于外周小动脉淋巴鞘或散在，而CD8^ T淋巴细胞则多存在于外周小动脉淋巴鞘和红髓。接种后胸腺中CD4^ 和CD8^ T淋巴细胞在皮质中减少，但在髓质增多，尤其是CD8^ T淋巴细胞数明显多于CD4^＋T淋巴细胞。盲肠扁桃体中CD4^ 和CD8^ T淋巴细胞主要存在于发生中心，尤其是CD8^ T淋巴细胞数比CD4^ T淋巴细胞明显多。骨髓和哈氏腺中也可见CD4^ 和CD8^ T淋巴细胞，而且CD8^ T淋巴细胞更多。在这些淋巴器官中，病毒损伤部位出现CD4^ 和CD8^ T淋巴细胞的迁入聚集，表明T淋巴细胞可能参与IBDV超强毒的免疫致病过程。 相似文献
8.
日龄白羽肉鸡和黄羽肉鸡免疫器官的组织学对比分析 《畜牧与饲料科学》2015,36(10):10-10
取42日龄白羽肉鸡和黄羽肉鸡的法氏囊、脾脏及胸腺,运用组织学常规切片技术和HE染色法,制作石蜡切片,在光学显微镜下逐一观察其组织结构,并对其进行显微照相,比较白羽肉鸡和黄羽肉鸡法氏囊、脾脏及胸腺组织形态的差异。结果表明,42日龄时,与黄羽肉鸡相比,白羽肉鸡法氏囊小结数量较少,皮质和髓质的分界更难分辨,并且固有层中出现大量空泡和间质结缔组织,淋巴细胞数量减少,表明免疫功能在减退;白羽肉鸡脾脏的白髓和红髓较明显,脾小结明显增大,脾小结内的淋巴细胞数量增加,排列密集,免疫功能较强;白羽肉鸡胸腺皮质部的强嗜碱性着染的小淋巴细胞较多,髓质内有更多典型的胸腺小体。这表明,同日龄的白羽肉鸡免疫器官的发育速度和功能建立要比黄羽肉鸡快,二者具有品种间差异。 相似文献
9.
本试验全面而系统地观察了传染性法氏囊病病毒变异Ｅ株,通过泄殖腔、鼻腔和尿囊腔接种雏鸡和鸡胚后不同时间法氏囊的组织形态学变化。结果表明,病毒感染后１２～４８小时,雏鸡法囊粘膜上皮细胞肿胀、坏死脱落,淋巴滤泡髓质部及皮质部淋巴细胞不同程度变性、坏死、排空,形成腺管样结构或囊状空泡,接毒后７２～１４４小时,法氏囊淋巴滤泡淋巴细胞坏死排空,淋巴滤泡萎缩,网状结缔组织大量增生,而胚胎发育时期,法氏囊粘膜上皮肿胀变性,法氏囊淋巴滤泡形成延迟或不完整,淋巴滤泡内淋巴细胞缺乏或空虚。探讨了传染性法氏囊病病毒对胚胎发育时期的雏鸡发育时期法氏囊生长发育的影响。 相似文献
10.
半胱胺对鸡免疫器官组织结构及发育的影响 总被引：1，自引：0，他引：1
为研究半胱胺对鸡免疫器官发育的影响,试验应用100羽1日龄草杂鸡,随机分成2组,每组50羽,即:对照组和试验组:分别饲喂添加0和1.0g/kg半胱胺的基础日粮.试验期30d.试验结束时每组随机抽取20只鸡,颈静脉放血致死,取胸腺、法氏囊和脾脏,应用Bouin液固定,制作石蜡切片,H·E染色,Olympus显微镜观察、拍照.结果表明,试验组鸡较对照组鸡胸腺小叶皮质增厚,皮质内淋巴细胞密集,胸腺小体减少;试验组较对照组鸡法氏囊淋巴小结增多,淋巴细胞处于发育状态,皮质较厚,皮质、髓质内淋巴细胞增多,皮质、髓质分界明显.对照组法氏囊出现萎缩退化现象;试验组鸡较对照组鸡脾脏的结构清晰,白髓内的脾小结数量增多,研究结果显示,日粮中添加半胱胺能够促进鸡的淋巴器官的发育,从而提高机体的免疫功能. 相似文献
11.
作者对３４头４～６月龄猪进行了猪丹毒的人工感染试验。试验分三组，每组又分免疫组和非免疫组。用四系强毒和自然野毒作为攻毒用菌种，静脉注射１００～５００亿活菌／头，接种３４头猪。２７头发病，死亡１５头，１～４天死亡９头；８头脾切面白髓周围出现“红晕”，出现率８８．８％；５～９天死亡猪脾切面眼观和组织学检查无“红晕”。本研究结果表明，只有病程为１～４天的特急性型死亡猪脾切面白髓切面白髓周围有“红晕”。本 相似文献
12.
Nuclear inclusion bodies typical of the adenovirus group were widespread in in the spleen and other tissues of 8-week-old turkeys with severe respiratory disease and concomitant evidence of colisepticemia. Adenoviral virions were seen in affected nuclei of splenic tissue and in negatively stained preparations of ground spleen. In splenic tissue, inclusions were most prominent in reticular cells and macrophages in the periarterial lymphoid sheaths, the red pulp and the marginal zones of the periarteriolar reticular sheaths. Marked reticuloendothelial hyperplasia, lymphoid atrophy and granulocytic splenitis characterized the splenic changes. There were inclusions in the respiratory tract, intestinal tract, liver, kidney and pancreas. Inoculation of young turkeys, especially when immunosuppressed, resulted in evidence of infection and respiratory disease. The viruses produced cytopathic changes in primary turkey kidney cell cultures but did not affect embryonating chicken eggs. Concentrated viral suspensions induced precipitin lines in agar gel immunodiffusion tests with known antisera against known turkey adenoviruses but did not show an antigenic relationship to chicken adenoviruses. 相似文献
13.
J H van Eck 《The Veterinary quarterly》1986,8(2):105-122
Cellular changes in spleens of mature fowl in relation to both the primary and secondary humoral antibody response following experimental EDS'76 virus infection were studied. The influence of splenectomy on humoral antibody response was also examined. Experimental fowl had been naturally infected with fowl adenovirus (FAV) but did not possess precipitins to these viruses at the time of EDS'76 virus infection. Since EDS'76 infection provokes a recall of the group antibody to FAV, this infection simultaneously induces a primary response against EDS'76 virus and a secondary response due to the recall of the group antibody to FAV. HI and precipitating antibody to EDS'76 virus (primary response) were first detected at 6 and 8 days p.i. respectively. Curves of HI, precipitating and neutralising antibody titres were biphasic; the first peak (IgM peak) occurred at 10-11 days p.i., the second (IgG peak) at 16-28 days p.i. Precipitating antibodies to FAV (secondary response) were demonstrated from 4 days p.i. The curve of these antibody titres was also biphasic, with peaks at the same times as in the primary response. Based on HI and AGP testing of primary and secondary immune response in both splenectomised and non-splenectomised fowl it is concluded that in the primary response the spleen of the adult fowl is involved significantly in only IgM secretion, while in the secondary response it is likely that both IgM and IgG are secreted in considerable amounts. Clusters of lymphoblasts and plasmablasts were observed at 3 days p.i. in the red pulp. It is very likely that antigen-antibody complexes are formed from that time and circulate bound to the surface of lymphocytes. These antigen-loaded lymphocytes are 'picked up' from the blood stream by -red pulp macrophages, leading to enhanced formation of lymphoblasts in the red pulp. Great numbers of these cells (which are very probably IgM secreting cells) were present on days 6 and 7 p.i., but were no longer detectable after day 10 p.i. -macrophages of the macrophagal ellipsoidal corona (MEC), leading to significant enlargement of the periellipsoidal lymphoid tissue (PELT) by an increase of the number of lymphocytes observed from days 4-12 p.i. The MEC was significantly enlarged from 7-12 days p.i., very likely due to an increased number of macrophages. Following deposition of antigen in the white pulp, formation of follicles begins. The number of small, intact follicles including follicle precursors increased from 6 days p.i.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
14.
J. H. H. van Eck 《The Veterinary quarterly》2013,33(2):105-122
Summary Cellular changes in spleens of mature fowl in relation to both the primary and secondary humoral antibody response following experimentalEDS'76 virus infection were studied. The influence of splenectomy on humoral antibody response was also examined. Experimental fowl had been naturally infected with fowl adenovirus (FAV) but did not possess precipitins to these viruses at the time of EDS’ 76 virus infection. Since EDS'76 infection provokes a recall of the group antibody to FAV, this infection simultaneously induces a primary response against EDS’ 76 virus and a secondary response due to the recall of the group antibody to FAV. HI and precipitating antibodies toEDS'76 virus (primary response) werefirst detected at 6 and 8 days p.i. respectively. Curves of HI, precipating and neutralising antibody titres were biphasic; the first peak (IgM peak) occurred at 10–11 days p.i., the second (IgG peak) at 16–28 days p.i. Precipitating antibodies to FAV (secondary response) were demonstrated from 4 days p.i. The curve of these antibody titres was also biphasic, with peaks at the same times as in the primary response. Based on HI and AGP testing of primary and secondary immune response in both splenectomised and non‐splenectomised fowl it is concluded that in the primary response the spleen of the adult fowl is involved significantly in only IgM secretion, while in the secondary response it is likely that bothIgM and IgG are secreted in considerable amounts. Clusters of lymphoblasts and plasmablasts were observed at 3 days p.i. in the red pulp. It is very likely that antigen‐antibody complexes are formed from that time and circulate bound to the surface of lymphocytes. These antigen‐loaded lymphocytes are ‘picked up’ from the blood stream by – red pulp macrophages, leading to enhanced formation of lymphoblasts in the red pulp. Great numbers of these cells (which are very probably IgM secreting cells) were present on days 6 and 7 p.i., but were no longer detectable after day 10 p.i. – macrophages of the macrophagalellipsoidal corona (MEC), leading to significant enlargement of the periellipsoidal lymphoid tissue(PELT) by an increase of the number of lymphocytes observedfrom days 4–12 p.i. The MEC was significantly enlarged from 7–12 days p.i., very likely due to an increased number of macrophages. Following deposition of antigen in the white pulp, formation of follicles begins. The number of small, intact follicles includingfollicle precursors increasedfrom 6 days p.i. From 15 days p.i. to the end of the experiment both the number and size of follicles increased significantly. Uptake and processing of antigen by macrophages is probably accompanied by death of some of these cells. This might explain the degenerative changes observed in large mesenchymal cells, probably macrophages, at 3 and 5 days p.i. in the red pulp and at 5 and 6 days especially in the MEC. Splenitis which was present at 3 and 5 days p.i. and oedema observed in and around ellipsoidal cells at 5 days p.i. may be due to mediators released from these degenerative macrophages. A significantly increased number of follicles with lymphoblasts was seen from 2–15 days p.i. while lymphoblasts and plasmablasts were present in the PELT from 5–15 days p.i., but predominantly at 6 and 7 days p.i. It is likely that disruption of follicles and blast transformation of white pulp lymphoid cells are secondary response events. White pulp lymphoblastsand plasmablastsare probably IgG secreting cells. Splenomegaly was observed at 3, 5 and 6 days after infection and was mainly due to swelling of red pulp macrophages and infiltration of granulocytes in the red pulp. Ellipsoidal and periellipsoidal changes could contribute to the splenomegaly at 5 and 6 days p.i. 相似文献
15.
雏鸡感染IBDV后法氏囊显微和超微结构的观察 总被引：1，自引：0，他引：1
运用光镜、电镜技术，观察了雏鸡实验感染传染性法氏囊病病毒（ＩＢＤＶ）后，其法氏囊显微和超微结构的动态变化。光镜观察表明，在感染早期，淋巴滤泡髓质部的淋巴细胞发生坏死，间质轻度水肿。感染后４ｄ，淋巴滤泡皮质内的毛细血管呈一典型的出血带环绕髓质，髓质部的淋巴细胞多已坏死、崩解。继之，整个淋巴滤泡呈网络状或囊状空泡。感染６ｄ以后，固有膜内的网状细胞和毛细血管大量增生，新的淋巴滤泡形成。电镜观察证明，在感染早期，淋巴细胞质内的内质网与核膜扩张，线粒体嵴紊乱或空泡化。继之，淋巴细胞核液化，细胞坏死、崩解。巨噬细胞和多核巨细胞大量出现，其胞浆内含有大量吞噬体和吞噬泡。 相似文献
16.
Role of the spleen and rosette-formation response in experimental Eperythrozoon ovis infection 总被引：1，自引：0，他引：1
The role of the spleen and rosette-formation responses was investigated in sheep experimentally infected with Eperythrozoon ovis. Phagocytic activity was observed in the spleen 19 days after primary infection. Phagocytosis of E. ovis-parasitised and non-parasitised erythrocytes by cordal reticular cells occurred. E. ovis organisms seemed to be detached from the erythrocytes by pseudopodia extending from macrophages and cordal reticular cells without causing damage to the plasmalemma of the erythrocyte. No phagocytic activity was observed in spleens removed 74 and 146 days after infection. Antigen-specific lymphoid cell responsiveness, assessed by rosette formation, indicated that 2.8, 15.4, 8.0 and 6.0% of lymphoid cells in the spleens of the four E. ovis-infected sheep, respectively, formed antigen-specific rosettes. Rosette formation did not occur when splenic lymphocytes from E. ovis-infected sheep were mixed with non-infected erythrocytes or when splenic lymphocytes from an uninfected sheep were used. 相似文献
17.
P C Stromberg G J Kociba I S Grants G S Krakowka J J Rinehart L E Mezza 《Veterinary pathology》1990,27(6):397-403
A spontaneous large granular lymphocyte leukemia from a F344 rat was transplanted to 36 syngeneic recipients to study the interactions among leukemia, T lymphocytes, and the development of immunemediated hemolytic anemia. Six rats were euthanatized at biweekly intervals, and spleen weight, total spleen cellularity, and differential spleen cell counts were correlated with hemograms and osmotic fragility. Sequential changes in splenic architecture were correlated with hematologic parameters. Monoclonal antibodies defining all T lymphocytes (W3/13), T helper-inducer cells (W3/25), and T suppressor cells (OX-8) were used to identify T cells in immunocytochemical techniques on spleen sections, as well as in fluorescence activated cell sorter analysis of spleen cell suspensions. The onset of hemolytic anemic at 7 weeks after transplantation coincided with the first detection of tumor cells in the spleen and peripheral blood. Tumor cells first accumulated in the marginal zones, and then they infiltrated the red pulp sinusoids. Although the leukemia caused dispersion of the splenic lymphoid tissue, there was no significant lymphopenia, and the relative number of helper (W3/25+) and suppressor (OX-8+) lymphocytes did not change. Because the induction of anemia was a relatively early event in splenic involvement, we concluded that anemia was unrelated to disruption of lymphoid architecture; furthermore, it does not appear to be caused by changes in the numbers of regulatory T lymphocytes. 相似文献
18.
Mbassa GK Kipanyula MJ Mellau LS Mwamakali ED Bulegeya FR Kauto-Mboni K 《Veterinary parasitology》2006,142(3-4):260-270
In a study of trends and magnitudes of lymphocytes proliferation, destruction or apoptosis eleven 3-month-old healthy calves were experimentally infected with the protozoan parasite Theileria parva, which is reported to cause lymphocyte proliferation. Four control calves were not infected. Infected and non-infected calves were sacrificed on days 9, 12, 16, 19, 23, 24 and 25 to examine lymphoid tissue changes and lymphocyte proliferation, apoptosis or necrosis in the thymus, spleen and lymph nodes. All infected calves developed severe East Coast fever, with enlargement of lymph nodes, dyspnoea, high fever and pulmonary oedema. Lymphocyte proliferation was not observed in lymph nodes, thymus and spleen; instead there were massive deaths of lymphocytes and other cells. The terminal severe disease caused massive lymphoid parenchyma coagulation terminating with caseation, organs and cells being undeterminable histologically. Tissues surrounding the lymph nodes were oedematous. Lymph node and thymus parenchyma were caseated and cortices and medulla indistinguishable because of severe lymphocyte and accessory cell deaths. The lymph node fibrous reticular stroma was necrotic and caseated. Lymphoid follicles in lymph nodes degenerated and lacked germinal centres. Lymph nodes, spleen and thymus were grossly enlarged, hardened, potato or cheese like, but microscopically very hypocellular and in the terminal disease acellular because of massive lymphocytes destruction. In the thymus there was extensive thymocyte and epithelioid cell necrosis and loss of distinction between cortex and medulla. The spleen white and red pulps were indistinguishable because of extensive lymphoid cell necrosis. The white pulp degenerated more than the red pulp. The massive lymphocyte deaths in the lymph nodes, thymus and spleen, without lymphocyte proliferation in this T. parva infection in calves leads to a conclusion that this parasite is lympho-destructive and lympho-degenerative in vivo rather than lympho-proliferative. 相似文献
19.
Lymphoid organs in sturgeons (Acipenseridae) 总被引：1，自引：0，他引：1
R F?nge 《Veterinary immunology and immunopathology》1986,12(1-4):153-161
Lymphoid (lymphomyeloid) tissues in sturgeons (hybrid sturgeon, Huso huso X Acipenser ruthenus, and white Pacific sturgeon, A. transmontanus) were investigated by dissection, histology and transmission electron microscopy. The main lymphomyeloid tissues are the thymus, the spleen, the anterior part of the kidney, the meningeal myeloid tissue, the pericardial tissue and lymphoid masses of the intestine, especially in the spiral valve. The kidney is the main hemopoietic tissue. The meningeal tissue is bone marrow-like (myeloid), mainly granulopoietic, but it also contains lymphoid elements. The pericardial tissue is predominantly lymphoid. The pericardial tissue has a lymph node-like appearance. It seems to be the site of interaction between lymphocytes and vascular endothelium. The thymus contains cortex and medulla. The spleen, as in higher vertebrates, is differentiated into white and red pulp. The highly diversiform and well developed lymphoid tissues of sturgeons may serve as basis of efficient immune mechanisms. 相似文献