固始鸡免疫器官内T淋巴细胞亚群动态变化

应用流式细胞仪结合免疫荧光抗体技术对固始鸡和固始鸡胚胎免疫器官内T淋巴细胞亚群的动态变化和发育分化规律进行了研究.结果发现,(1)胚胎时期,胸腺内T淋巴细胞发育分化低,表现为成熟的T淋巴细胞(CD3~+)和不成熟的胸腺细胞均较少;出壳后,固始鸡胸腺内成熟T淋巴细胞增多,占胸腺细胞的30%左右,但大部分仍是未成熟的胸腺细胞.(2)脾脏内T淋巴细胞为成熟的T淋巴细胞(CD3~+),占淋巴细胞的60%左右.胚胎时期脾脏内CD3~+水平低,出壳后2周已达脾脏内正常水平(60%左右).(3)法氏囊内有少量的成熟T淋巴细胞(10%左右).结果表明,T淋巴细胞在固始鸡胸腺内增殖分化和成熟,脾脏和法氏囊内的成熟T淋巴细胞均来源于胸腺.     

仔猪非特异性免疫系统的组成及发育过程

1组成 仔猪的免疫系统由具有免疫作用的细胞及其相关组织和器官组成,是产生主动免疫力的物质基础,包括中枢和外周免疫器官。仔猪的中枢免疫器官包括骨髓和胸腺,是淋巴细胞等免疫细胞发生、分化和成熟的地方。胸腺作为T细胞成熟的场所,也产生胸腺激素。     

雏鸡淋巴细胞变化规律的流式细胞仪检测研究

为进一步研究鸡在出孵1个月左右时间内T、B淋巴细胞及其亚群的发育状况，将SPF雏鸡分别在3、5、7、9、11、14、17、22、27、32日龄时取血液、脾脏、法氏囊及胸腺，分离并制成淋巴细胞悬液，流式细胞仪双染色法检测Bu-la^＋B淋巴细胞、CD3^＋、CD4^＋、CD8^＋和TCRγδ^＋CD3^＋T淋巴细胞含量及血液淋巴细胞的凋亡规律。结果：在出孵1个月内T、B细胞处于分化发育阶段的初期，除胸腺外，呈上升趋势，但T细胞亚群的变化无规律，B细胞在法氏囊中和T细胞在脾脏中3～9日龄发育最快；血液淋巴细胞凋亡趋于下降，尤其是在9日龄以后：此间不断有成熟的淋巴细胞产生，不断进入血液和脾脏，使其数量有上升趋势。但是，血液中第7日龄时Bu—la^＋B淋巴细胞和CD3^＋、CD4^＋、CD8^＋T淋巴细胞数量均最低，说明体液免疫和细胞免疫水平第7日龄时都最低，并在17日龄时进入水平较高的又一个低谷。TCRγδ^＋CD3^＋T细胞则变化幅度不大。     

板蓝根多糖对缺乳仔鼠免疫器官发育及T淋巴细胞亚群的影响

应用流式细胞仪检测缺乳仔鼠CD3+、CD4+和CD8+T淋巴细胞含量,研究添加不同剂量的板蓝根多糖(RIP)对缺乳仔鼠免疫器官及T淋巴细胞亚群的影响。结果表明,RIP可以提高缺乳仔鼠胸腺指数和脾脏指数,对胸腺指数和脾脏指数效果最佳的RIP剂量随日龄增大而减小;RIP可以增加缺乳仔鼠外周血CD3+、CD4+、CD8+T淋巴细胞数量,CD3+T淋巴细胞数量在7-28日龄时,A、C、D组与B组差异显著(P0.05);CD4+T淋巴细胞数量在7-21日龄时,A、C、D组与B组差异显著(P0.05);各处理组CD3+、CD4+、CD8+T淋巴细胞数量以及CD4+/CD8+比值随着日龄的增加有所下降。结果表明,一定剂量的RIP可以促进缺乳仔鼠免疫器官发育,提高T淋巴细胞亚群的水平。     

PRRSV特异性肽对猪骨髓、脾脏、胸腺、肺门淋巴结中T细胞表型的影响

通过猪繁殖与呼吸障碍综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV)特异性肽PRRSV-GP5(GP5aa96-104)、PRRSV-N(Naa49-57)刺激PRRS免疫后的仔猪骨髓、脾脏、胸腺、肺门淋巴结,用流式细胞仪检测T淋巴细胞表型的变化。结果显示:(1)骨髓和脾脏T细胞受到刺激时,首先转化为以CD4~+ T细胞为主,而胸腺和肺门淋巴结主要转化为以CD8~+ T细胞为主,并产生CD4~+ CD8~+ T细胞。其中,胸腺和肺门淋巴结中CD4的降低为一过性降低。(2)N特异性肽对骨髓CD3~+ 和CD4~+ CD8~+ T细胞有抑制作用,对脾脏和肺门淋巴结中的CD3~+ T细胞有促进作用,该抑制作用在48h后得以改善。(3)胸腺中T淋巴细胞转化能力最持久。(4)骨髓中T淋巴细胞开始以CD4~+ T细胞为主,后转为以CD8~+ T细胞为主。这为进一步研究有效防制PRRS的途径提供理论数据。     

雏鸡T淋巴细胞及其亚群的变化规律

白细胞分化抗原是白细胞在分化成熟为不同谱系和分化不同阶段以及活化过程中 ,出现或消失的细胞表面标记 [1]。鸡的 T淋巴细胞表面分化抗原的研究近年来进展较快 ,证明与哺乳动物的 T淋巴细胞表面分化抗原有许多相似之处 ,尤其以 CD3,CD4,CD8为突出。 CD3分子表达于所有成熟 T细胞表面 ,可与 TCR( T细胞抗原识别受体 )分子以非共价结合形成一个 TCR- CD3复合物 ,其中 TCR是识别异种抗原和自身 MHC分子多态性决定簇的受体 ,而 CD3分子具有稳定 TCR结构和传递活化信号的作用 [2 ] ,CD3是鉴定 T细胞的重要标记。T细胞可分为辅助…     

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

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。     

IGF-Ⅰ对初生宫内发育迟缓猪T细胞发育的影响

为研究IGF-Ⅰ对宫内发育迟缓(IUGR)猪胸腺T淋巴细胞分化的促进作用及Notch通路的调控作用,本实验在新生IUGR仔猪胸腺细胞培养体系中添加浓度为0、10、50、100 ng/mL的IGF-Ⅰ,以完全培养基培养的正常仔猪和IUGR仔猪胸腺T细胞分别作为正、负对照组。结果表明:培养第1天,IGF-Ⅰ处理组CD4~+和CD8~+T细胞比例均比正、负对照组高(P0.05);培养第3天,IGF-Ⅰ10 ng/mL组CD4~+T细胞比例最高,且正对照组显著高于负对照组(P0.05),但对于CD8~+T细胞来说,IGF-Ⅰ100 ng/mL组最高;培养第5天,正对照组CD4~+、CD8~+T细胞比例都最高,但50 ng/mL IGF-Ⅰ组显著高于负对照组(P0.05)。在培养全期,IGF-Ⅰ处理组Delta-like1 mRNA表达量均显著高于负对照组(P0.05),在第1天,IGF-Ⅰ10、50 ng/mL组Delta-like1 mRNA表达量低于正对照组(P0.05),然而,第3、5天则高于正对照组(P0.05)。Delta-like4和Notch2 mRNA的表达趋势与Delta-like1 mRNA的相似。本试验结果证明,IGF-Ⅰ能不同程度地改善IUGR猪T细胞的发育,促进CD4~+和CD8~+T细胞的转化与增殖,最佳剂量为IGF-Ⅰ10 ng/mL,培养时间不能超过3 d。IGF-Ⅰ可通过调控Delta-like4、Delta-like1和Notch2的基因表达来双阳性T细胞分化为CD4~+和CD8~+T细胞。     

小鼠胸腺胚后发育的组织学观察和外周血T淋巴细胞亚群的动态变化

为了研究动物胸腺发育结构与功能的关系,本试验以健康昆明小鼠为研究对象,通过组织形态和流式细胞术研究不同日龄小鼠胸腺的形态特点和淋巴细胞亚群的动态变化。结果表明:随着日龄的增加,小鼠胸腺髓质逐渐增宽,胸腺小体增多,结缔组织增加并分隔胸腺形成明显的小叶结构;外周血CD3+、CD3+CD4+、CD3+CD8+T淋巴细胞逐渐增多。可见小鼠到50日龄时胸腺已开始发育成熟,免疫功能逐渐增强。     

胸腺外CD4和CD8双阳性T细胞的研究概述

胸腺依赖性细胞即 T细胞具有多种重要的免疫功能 ,不同的免疫功能与其细胞膜上的分化抗原 (CD)的种类相关联。其中 CD4和 CD8是关键的分化抗原。 CD4分子是单链糖蛋白 ,是自身主要组织相容性复合体 (MHC) 类抗原的受体。研究表明 ,其功能性分子可能是低聚体 [1 ] 。CD8分子也是糖蛋白 ,包含α链和β链 ,是 MHC 类抗原的受体。 CD4和 CD8与相应 MHC抗原结合是 T细胞在胸腺外发挥免疫功能的生化基础 ,也与 T细胞在胸腺微环境中的分化有关。来自骨髓的前 T细胞表面无任何 CD标志 ,在胸腺微环境中先后表达CD2、CD7、CD3抗原和 T…     

Effects of chicken thymic stromal cells on the growth and differentiation of thymocytes in vitro

We examined contact-mediated effects of chicken thymic stromal cells (TSC) on thymocyte differentiation by co-cultivation of these cell populations. The primary cultures of TSC isolated from thymus mainly have consisted of epithelial cells which were polygonal in shape, possessed long processes and expressed MHC class II antigen. When thymocytes were co-cultured with TSC, 60% to 70% of thymocytes attached to TSC and some of them engulfed underneath TSC. These attached thymocytes were CD4-CD8- and CD4+CD8+ subsets and expressed alpha/beta TCRhigh or gamma/delta TCRlow. Some of the thymocytes attaching to TSC showed an increase of intracellular and nuclear density, fragmentation of cytoplasm and nuclei, and DNA fragmentation. And also, thymocytes attaching to TSC contained a higher percentage of cycling (S and G2 + M phase) cells than nonattaching cells. These results indicate that specific subsets in thymocytes selectively bind to TSC and undergo apoptotic death or proliferation because of interaction with TSC. Chicken TSC may play an important role in thymic differentiation by direct contact within the thymus as in mammals.     

Regulation of early chicken thymocyte proliferation by transforming growth factor-beta from thymic stromal cells and thymocytes

We examined expression of TGF-betas in chicken thymic stromal cells and thymocytes and roles of TGF-betas in thymocyte development within the thymus. Thymic stromal cells expressed TGF-beta 2 and 3 genes but not TGF-beta 4 gene. Thymocytes showed expressions of TGF-beta 2, 3 and 4 genes and each TGF-beta gene was expressed more strongly in CD3- than CD3+ thymocytes. When anti-TGF-beta antibody was added with supernatants of stromal cells into thymocyte culture, only proliferative activity of CD3- thymocytes was enhanced and the cells in S and G2/M compartments of cell cycle increased. These results suggest that TGF-beta which is expressed in the thymus may regulate the ability of immature thymocytes to progress through the cell cycle and to differentiate to CD3+ thymocytes.     

Characterization of CD34⁺ thymocytes in newborn dogs

Using two-color flow cytometry, we characterized CD34(+) cells in the newborn canine thymus. CD34(+) thymic cells comprised approximately 5% of cells recovered by thymus tissue teasing and both large and small thymocytes have been present in this population, the former being 7-12 times more frequent. All CD34(+) cells expressed the pan-leukocyte antigen CD45. The expression of CD44 profile on the large and small CD34(+) thymocytes differed: almost all large CD34(+) cells were CD44(+), while only 75% of small CD34(+) thymocytes co-expressed the CD44 antigen. We have previously described that CD172α is present on the surface of CD34(+) bone marrow cells in dogs. In the thymus, CD172α was expressed on 5-10% and less than 5% of large and small CD34(+) cells, respectively. Some CD34(+) thymocytes also co-expressed T-lineage-specific markers like CD3, CD4, CD8, TCR1 and TCR2. Their expression increased during the large-to-small thymocyte transition. Based on our findings we suggest that thymocyte progenitors enter their primary differentiation center as large CD34(+), CD44(+), CD45(+) and CD172α(+) cells. T-cell specific markers appear on their surface at early stages of differentiation. As the size of progenitors decreases with terminal primary differentiation, the CD34, CD44, and CD172α surface markers are down-regulated.     

Effects of cytokines from thymocytes and thymic stromal cells on chicken intrathymic T cell development

We have studied the ability of thymic stromal cells (TSC) and thymocytes to produce cytokines and the involvement of cytokines in intrathymic T cell development. When thymocytes were co-cultured with thymic stromal cells in absence of direct contact and mitogenic stimulation, induction of thymocyte proliferation was observed. Supernatants of cultured stromal cells (TSC-CS) promoted a high proliferative response on CD3- thymocytes but had little effect on CD3+ thymocytes. These results indicate that stromal cells have produced a cytokine which can induce immature thymocyte proliferation. Moreover, stromal cells express the MRNA for stem cell factor (SCF) and c-kit (the receptor for SCF) was detected on CD3- thymocytes but not on CD3+ thymocytes. Since SCF can enhance the proliferation of immature thymocytes in synergy with IL-7 in mammals, there is a possibility that chicken stromal cells may produce a IL-7-like factor. Thymocytes have clearly expressed interferon (IFN)-gamma. In contrast, thymic stromal cells showed no detectable expression of IFN-gamma. CD3+ thymocytes express IFN-gamma MRNA more strongly than CD3 thymocytes, suggesting that IFN-gamma from thymocytes may operate on stromal cells and then may indirectly induce clonal elimination of CD3+ cells on stromal cells. The expression of these cytokines and receptors by thymic stromal cells and thymocyte subpopulations suggests that these cytokines participate in paracrine interactions between these cell populations during thymocyte differentiation.     

Influence of bestatin, an inhibitor of aminopeptidases, on T and B lymphocyte subsets in mice

Bestatin, a low-molecular weight dipeptide, is a potent inhibitor of aminopeptidase N which has been demonstrated to have antitumor and immunomodulatory effects. The effects of bestatin (10, 1 and 0.1 mg/kg) administered intraperitoneally once, five or ten times to mice on the total number of lymphocytes in the thymus, spleen and mesenteric lymph nodes and the percentage and the absolute number of T cell subsets (CD4+CD8+, CD4-CD8-, CD4+, CD8+) in the thymus and T (CD3+, CD4+, CD8+) and B (CD19+) lymphocytes in the spleen and mesenteric lymph nodes were studied. It has been found that bestatin administered ten times at doses of 10, 1 and 0.1 mg/kg increased the total number of thymocytes, splenocytes and lymphocytes of mesenteric lymph nodes. Bestatin also changed the percentage and the absolute number of T cell subsets in the thymus and T and B lymphocytes in the peripheral lymphatic organs. Five and ten exposures to bestatin (10, 1 and 0.1 mg/kg) increased the absolute count of both immature CD4+CD8+ and CD4-CD8- thymic cells. Moreover, both a single and multiple administration of bestatin (1 and 0.1 mg/kg) decreased the percentage and absolute count of CD3+ splenocytes and mesenteric lymph node cells with corresponding decreases in the percentage and absolute count of CD4+ and CD8+ cells. Both a single and multiple administration of bestatin at all the doses under investigation augmented the percentage and the absolute count of CD19+ (B lymphocytes) in the peripheral lymphatic organs. The results of the study show that there is a relationship between the effect induced by bestatin and the dose of the drug as well as the number of doses applied. The strongest effect on the T and B lymphocyte subsets was noted after five injections of bestatin at doses of 1 and 0.1 mg/kg.     

The effects of florfenicol on lymphocyte subsets and humoral immune response in mice

Florfenicol is a broad-spectrum bacteriostatic antibiotic used in domestic animals. The aim of the study was to determine the effect of florfenicol on the total number of lymphocytes in the thymus, spleen and mesenteric lymph nodes and the percentage and the absolute number of T cell subsets (CD4+CD8+, CD4-CD8-, CD4+, CD8+) in the thymus and T (CD3+, CD4+, CD8+) and B (CD19+) lymphocytes in the peripheral lymphatic organs in non-immunized mice and humoral immune response in sheep red blood cells (SRBC)-immunized mice. Florfenicol was administered orally at a dose of 30 mg/kg six times at 24 h intervals to non-immunized mice and four or seven times at 24 h intervals to SRBC-immunized mice. SRBC was injected 2 hours prior to the first dose of the drug. Florfenicol increased the percentage of CD4CD8- thymocytes and the absolute number of CD4+ and CD8+ thymocytes on day 7. The increased percentage and absolute number of CD3+, CD4+ and CD8+ lymphocytes in mesenteric lymph nodes and decreased percentage of lymphocytes B were also observed 24 hours from the last administration of florfenicol. Florfenicol administered after SRBC immunization reduced the number of plaque forming cells (PFC) and the production of anti-SRBC antibodies on days 4 and 7 after priming.     

Biology of porcine T lymphocytes

The present review concentrates on the biological aspects of porcine T lymphocytes. Their ontogeny, subpopulations, localization and trafficking, and responses to pathogens are reviewed. The development of porcine T cells begins in the liver during the first trimester of fetal life and continues in the thymus from the second trimester until after birth. Porcine T cells are divided into two lineages, based on their possession of the alphabeta or gammadelta T-cell receptor. Porcine alphabeta T cells recognize antigens in a major histocompatibility complex (MHC)-restricted manner, whereas the gammadelta T cells recognize antigens in a MHC non-restricted fashion. The CD4+CD8- and CD4+CD8lo T cell subsets of alphabeta T cells recognize antigens presented in MHC class II molecules, while the CD4-CD8+ T cell subset recognizes antigens presented in MHC class I molecules. Porcine alphabeta T cells localize mainly in lymphoid tissues, whereas gammadelta T cells predominate in the blood and intestinal epithelium of pigs. Porcine CD8+ alphabeta T cells are a prominent T-cell subset during antiviral responses, while porcine CD4+ alphabeta T cell responses predominantly occur in bacterial and parasitic infections. Porcine gammadelta T cell responses have been reported in only a few infections. Porcine T cell responses are suppressed by some viruses and bacteria. The mechanisms of T cell suppression are not entirely known but reportedly include the killing of T cells, the inhibition of T cell activation and proliferation, the inhibition of antiviral cytokine production, and the induction of immunosuppressive cytokines.     

Canine X-linked severe combined immunodeficiency.

Canine X-linked severe combined immunodeficiency (XSCID) is due to mutations in the common gamma (gamma c) subunit of the IL-2, IL-4, IL-7, IL-9 and IL-15 receptors. The most striking clinical feature is a failure to thrive or 'stunted' growth. Recurrent or chronic infections begin at the time of decline of maternal antibody, usually between six and eight weeks of age. Affected dogs rarely survive past three to four months of age. The major pathologic feature of canine XSCID is a small, dysplastic thymus. Grossly identifiable lymph nodes, tonsils, and Peyer's patches are absent in XSCID dogs. During the neonatal period, XSCID dogs have few, if any, peripheral T cells and increased number of peripheral B cells. Some XSCID dogs do develop phenotypically mature, nonfunctional T cells with age, however, the absolute number of peripheral T cells remain significantly decreased compared to age-matched normal dogs. An interesting finding is that as soon as T cells begin to appear in XSCID dogs they rapidly switch from a CD45RA+ (naive) phenotype to a CD45RA- (activated or memory phenotype). One of the characteristic findings in XSCID dogs is an absent or markedly depressed blastogenic response of T cells in response to stimulation through the T cell receptor and when the necessary second messengers for cellular proliferation are directly provided that by-pass signals delivered through ligand-receptor interaction. The proliferative defect is due to the inability of T cells to express a functional IL-2 receptor. Canine XSCID B cells do not proliferate following stimulation with T cell-dependent B cell mitogens, however, they proliferate normally in response to T cell-independent B cell mitogens. Canine XSCID B cells are capable of producing IgM but are incapable of class-switching to IgG antibody production following immunization with the T cell-dependent neoantigen, bacteriophage phiX174. The number of thymocytes in the XSCID thymus is approximately 0.3% of the thymocytes present in the thymus of age-matched normal dogs. The proportion of CD4-CD8- thymocytes in XSCID dogs is increased 3.5-fold and the CD4+CD8+ population is decreased 2.3-fold. These findings demonstrate that (1) a functional gamma c is required for normal B and T cell function, (2) early T cell development is highly dependent upon a functional gamma c, and (3) B cell development can occur through a gamma c-independent pathway.     

葡萄球菌性关节炎肉鸡免疫器官的病理学变化

利用鸡源致病性金黄色葡萄球菌复制鸡葡萄球菌性关节炎的病理模型,研究免疫器官的主要病理学变化及其内CD4 和CD8 T淋巴细胞的动态变化。结果表明:鸡接种细菌后呈典型的关节炎症状。脾脏肿大,表面呈网格状,法氏囊黏膜增厚,盲肠扁桃体和胸腺上散在出血点。光镜下脾脏淋巴小结早期数目增多,后期呈灶状坏死,法氏囊水肿,淋巴小结坏死液化。CD4 和CD8 T淋巴细胞的变化为:脾脏在接种后7 d淋巴小结内的CD4 和CD8 T淋巴细胞已明显多于对照组,与对照组比差异极显著(P<0.01);接种后7 d,法氏囊的淋巴滤泡周围的间隙中检出较多的阳性细胞,在接种后14 d CD4 T淋巴细胞达到高峰,随后下降,与对照组相比在接种后7 d差异显著(P<0.05),在接种后14 d差异极显著(P<0.01);而CD8 T淋巴细胞在接种后7 d就达到高峰,与对照组相比差异极显著(P<0.01);盲肠扁桃体的CD8 T淋巴细胞在接种后7 d上升,21 d达到最高值;胸腺组织中阳性细胞数对照组和试验组都很少,试验组的阳性细胞数的变化没有明显的规律。鸡接种金黄色葡萄球菌后免疫器官内CD4 和CD8 T淋巴细胞数目增多,表明T淋巴细胞参与了金黄色葡萄球菌引起鸡的关节炎的发生发展过程。