柔嫩艾美耳球虫对藏鸡和隐性白羽鸡致病性差异分析

为进一步明确柔嫩艾美耳球虫对球虫易感性差异鸡种的致病性,本研究以1×10⁵个柔嫩艾美耳球虫孢子化卵囊的剂量分别感染对球虫具有抗性的藏鸡和易感的隐性白羽鸡,接种后观察记录各组鸡的临床表征、血便记分、死亡率、增重、盲肠病变记分、卵囊产量,并于感染前和感染后3、6和8 d每个品种分别随机选择5只鸡采集抗凝血,应用流式细胞仪（FCAS）检测外周血CD4⁺T和CD8⁺T淋巴细胞亚群数量。结果显示,柔嫩艾美耳球虫感染后藏鸡相对增重率高于隐性白羽鸡,死亡率、血便记分和盲肠病变记分均低于隐性白羽鸡,但卵囊产量高于隐性白羽鸡。外周血T淋巴细胞亚群变化方面,感染前,藏鸡CD4⁺T淋巴细胞数及CD4⁺/CD8⁺比值均高于隐性白羽鸡。感染后第3天,藏鸡CD4⁺、CD8⁺ T淋巴细胞数及CD4⁺/CD8⁺比值下降,隐性白羽鸡CD8⁺ T淋巴细胞数略有下降,CD4⁺T淋巴细胞数及CD4⁺/CD8⁺比值上升,但CD4⁺/CD8⁺比值仍显著低于藏鸡（P<0.05）。感染后第6天,2个品种鸡CD4⁺ T淋巴细胞数及CD4⁺/CD8⁺比值均下降,其中藏鸡表现为显著下降（P<0.05）,而隐性白羽鸡仅CD4⁺/CD8⁺比值显著降低（P<0.05）,隐性白羽鸡CD8⁺ T淋巴细胞数显著升高（P<0.05）。感染后第8天,2个品种鸡CD4⁺/CD8⁺比值显著下降（P<0.05）,藏鸡CD8⁺ T淋巴细胞数显著高于隐性白羽鸡（P<0.05）,但CD4⁺/CD8⁺比值显著低于隐性白羽鸡（P<0.05）。结果表明,球虫对藏鸡和隐性白羽鸡的致病性存在差异,这种差异与T淋巴细胞介导的免疫应答反应密切相关。     

禽网状内皮组织增生病病毒感染对SPF雏鸡血液和局部淋巴组织CD4+/CD8+细胞及相关细胞因子表达的影响

旨在探讨禽网状内皮组织增生病病毒（reticuloendotheliosis virus,REV）对SPF雏鸡血液和局部淋巴组织中T淋巴细胞数量以及相关细胞因子表达的影响。将96只1日龄SPF雏鸡随机分为REV感染组和对照组,应用流式细胞术、酸性α-醋酸萘酯酶染色（acid α-naphthyl acetate esterase,ANAE）、荧光定量PCR等方法对上述指标进行检测。试验数据表明,与对照组相比,感染组雏鸡血液CD4⁺T淋巴细胞数量在第7~35天显著降低、CD8⁺T淋巴细胞数量在第7~28天显著升高,CD4⁺/CD8⁺比值在第7~28天显著降低（均P<0.05或P<0.01）;局部淋巴组织哈德尔腺（Hader’s gland,HG）、派伊尔结（Peyer’s patch,PP）和盲肠扁桃体（caecal tonsil,CT）中ANAE⁺T淋巴细胞数量均显著降低（均P<0.05或P<0.01）;GH、PP和CT中细胞因子IL-2、IFN-γ和TNF-α 转录量都有不同程度升高。本研究表明,REV感染引起雏鸡血液中CD4⁺ T淋巴细胞数量降低、CD4⁺/CD8⁺T淋巴细胞比例失衡、局部淋巴组织中T淋巴细胞数量相对减少及细胞因子TNF-α转录持续升高与REV造成感染雏鸡细胞免疫功能显著降低密切相关。     

芹菜发酵液对小鼠溃疡性结肠炎的保护作用研究

本试验旨在研究发酵前后芹菜汁的主要功能成分变化和芹菜发酵液对葡聚糖硫酸钠（DSS）诱导的小鼠溃疡性结肠炎（UC）的防治及免疫调节作用。选取50只4周龄雄性C57BL/6小鼠随机分为空白组、模型组及低、中、高浓度芹菜发酵液组,每组10只。按10 μL/g BW的剂量标准给空白组和模型组小鼠灌胃无菌生理盐水,其他组小鼠则灌胃不同浓度的芹菜发酵液,持续7 d。从第8天开始,除空白组自由饮用无菌水外,其余组连续7 d自由饮用3% DSS溶液;在此过程,每日称量体重,进行疾病活动指数（DAI）评分。在第14天,通过摘眼球取血法获得全血,随后脱颈处死小鼠,解剖取出结肠组织测量长度并通过苏木素-伊红（HE）染色法制作病理切片,进行病理学分析。以流式细胞仪分选技术检测外周血中CD4⁺/CD8⁺T淋巴细胞比值,以酶联免疫吸附法（ELISA）检测血清中肿瘤坏死因子-α（TNF-α）、白细胞介素-6（IL-6）、γ-干扰素（IFN-γ）和IL-10的含量。结果表明：①芹菜汁经发酵后,总酸、总糖、总多酚、类黄酮、维生素C和超氧化物歧化酶（SOD）等多种活性成分的含量均显著增加（P<0.05）。②与模型组相比,芹菜发酵液高浓度组能减少DSS引起的小鼠体重损失（P<0.01）、结肠缩短（P<0.01）和DAI降低（P<0.05）。③组织病理学分析结果表明,各发酵液组的UC症状均得到不同程度改善,肠腺结构相对完整,杯状细胞轻微减少,仅有少量淋巴细胞和中性粒细胞浸入。④流式细胞仪分析结果显示,相较于模型组,发酵液组全血CD4⁺/CD8⁺T淋巴细胞比值极显著升高（P<0.01）。⑤ELISA检测结果显示,与模型组相比,芹菜发酵液组的IL-6、TNF-α和IFN-γ含量极显著下调（P<0.01）,IL-10的含量极显著上调（P<0.01）。综上,芹菜汁经发酵后主要功能活性成分均得到显著提高,并且发酵芹菜液对DSS诱导的小鼠UC具有一定的防治和免疫调节作用,其作用机制可能与维持外周血中CD4⁺与CD8⁺T淋巴细胞平衡,以及抑制促炎症因子（TNF-α、IL-6和IFN-γ）表达,促进抗炎症因子（IL-10）表达有关。     

成年牦牛皮肤中血管与神经的组织学观察及HIF-1α在皮肤中的表达

本研究旨在探讨牦牛不同部位皮肤内血管和神经的分布情况,及检测低氧诱导因子-1α（HIF-1α）在不同部位皮肤上的定位及相对表达量,探究牦牛皮肤对高原低氧环境的适应机制。采用HE、Masson’s三色和Verhoeff VG染色法,对成年牦牛皮肤内血管和神经结构进行观察与分析;采用免疫组织化学、实时荧光定量PCR和蛋白免疫印迹法,对HIF-1α的mRNA和蛋白在成年牦牛皮肤组织中表达与分布进行研究。结果表明,颈部血管与神经密度最高,前臂部和小腿部次之,跖部最低,部位间差异显著（P<0.05）。HIF-1α主要表达在表皮层、毛囊的上皮根鞘、皮脂腺、汗腺、血管、神经;颈部、前臂部和小腿部强阳性表达,跖部阳性表达。HIF-1α mRNA的相对表达量跖部明显低于其他部位（P<0.05）,其他三个部位两两比较差异不显著（P>0.05）。HIF-1α蛋白相对表达量颈部最高,跖部最低,差异显著（P<0.05）。研究结果提示,成年牦牛不同部位皮肤内不同血管和神经形态结构相似,密度从颈部到前肢再到后肢差异显著。HIF-1α的差异性表达进一步说明皮肤在牦牛适应低氧环境中发挥作用。     

黄牛呼吸道CD3+淋巴细胞分布的研究

CD3⁺是T细胞群的重要表面标志,呼吸道黏膜下分布的CD3⁺淋巴细胞作为抗感染黏膜免疫的基础,在保护机体抵抗呼吸道感染中发挥重要作用。为了解黄牛呼吸道CD3⁺淋巴细胞和淋巴组织的分布,本研究运用HE染色法和免疫组织学方法对5头7岁健康婆罗门黄牛的鼻黏膜、气管、肺内支气管及肺脏组织的CD3⁺淋巴细胞和淋巴组织的分布进行了研究。结果显示,黄牛的鼻黏膜、气管、肺内支气管和肺脏组织中均分布有CD3⁺淋巴细胞,且主要分布于黏膜上皮间及其下方固有层中及腺体周围;在鼻黏膜和肺脏组织中分布有CD3⁺淋巴细胞形成的弥散淋巴组织。牛呼吸道中CD3⁺淋巴细胞数量在鼻黏膜和肺脏组织中分布最多,气管黏膜、肺内支气管黏膜次之。本试验结果明确了CD3⁺淋巴细胞在黄牛呼吸道中的分布谱,表明黄牛呼吸道具备引发局部黏膜免疫的基础条件,为牛呼吸道黏膜免疫及呼吸道疾病防治研究提供了数据支撑。     

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

试验应用流式细胞术检测缺乳仔鼠CD3⁺、CD4⁺和CD8⁺ T淋巴细胞含量来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:①RIP可增加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好的RIP剂量随日龄增大而减小。②RIP可以增加缺乳仔鼠外周血CD3⁺、 CD4⁺ 、CD8⁺ T淋巴细胞数量。7~28日龄时初乳组(A组)、缺乳+中RIP组(C组)和缺乳+高RIP组(D组)3组CD3⁺ T淋巴细胞含量与缺乳组(B组)相比差异显著(P<0.05)。7~21日龄时初乳组(A组)、缺乳+中RIP组(C组)和缺乳+高RIP组(D组)3组CD4⁺ T淋巴细胞含量与缺乳组(B组)相比差异显著(P<0.05)。各处理组CD3⁺、 CD4⁺、CD8⁺ T淋巴细胞含量及CD4⁺/CD8⁺比值随着日龄的增加有所下降。适宜剂量的RIP可促进缺乳仔鼠免疫器官发育,提高T淋巴细胞亚群的水平。     

伯氏疟原虫ANKA株感染小鼠的T细胞、NK细胞及细胞因子变化

旨在系统分析伯氏疟原虫感染引起宿主T细胞、NK细胞、Tim-3表达及细胞因子的变化。选取64只雌性C57BL/6小鼠随机分为8组,每组8只,分别于感染后0、4、7、9、11、13、16和19 d获取小鼠脾及外周血免疫细胞,利用流式细胞术检测小鼠主要免疫细胞亚群及免疫检查点分子Tim-3表达水平的变化;同时检测血清中细胞因子的变化。结果表明,感染疟原虫后,小鼠脾CD3⁺CD4⁺ T细胞、CD3⁺CD8⁺ T细胞及NK细胞的比例均逐渐降低（P<0.01）,且伴随着3种细胞Tim-3表达量的升高（P<0.01）。小鼠外周血CD3⁺CD4⁺ T细胞的比例呈先降低后升高趋势,CD3⁺CD8⁺ T细胞的比例呈先升高后降低趋势（P<0.05）;小鼠外周血CD3^-NK1.1⁺细胞的比例呈先降低后升高趋势,但感染末期,其比例仍低于未感染组（P<0.05）。Tim-3分子在外周血CD3⁺CD4⁺ T细胞、CD3⁺CD8⁺ T细胞及CD3^-NK1.1⁺细胞的表达均显著升高（P<0.05）。感染疟原虫后,小鼠血清中促炎细胞因子IL-2的分泌量均显著高于未感染组（P<0.05）;促炎细胞因子IFN-γ、TNF-α和IL-6在血清中分泌均呈先升高后降低趋势（P<0.05）;具有免疫抑制作用的细胞因子IL-10呈逐渐升高趋势,且感染后期急剧升高（P<0.001）。以上结果表明,感染疟原虫后,小鼠的特异性免疫反应发挥了一定的杀伤作用,但由于Tim-3免疫检查点分子及一些发挥免疫抑制作用的细胞因子（IL-10）的过度表达,有利于疟原虫逃避宿主的免疫捕杀作用。该研究提示了从宿主免疫抑制角度研究疟原虫感染的重要性。     

灭活大肠杆菌与脂多糖诱导猪肠黏膜上皮细胞表达RegⅢγ的机理研究

试验旨在探索革兰氏阴性菌大肠杆菌（Escherichia coli,E.coli）及其表面分子脂多糖（LPS）诱导胰腺再生蛋白Ⅲγ（RegⅢγ）表达调控的机制。首先,用不同浓度灭活E.coli（10⁹、10⁸、10⁷、10⁶、10⁵、10⁴ CFU/mL）和LPS （0.01、0.1、1、5、10、20、40、80 μg/mL）诱导猪肠黏膜上皮细胞（IPEC-JⅡ）,用MTT法测D_{490 nm}值,检测E.coli和LPS对IPEC-JⅡ细胞活力的影响;其次,用不同浓度灭活E.coli（10⁷、10⁶、10⁵ CFU/mL）和LPS （0.01、0.1、1、5 μg/mL）处理IPEC-JⅡ细胞24 h,用实时荧光定量PCR和Western blotting检测RegⅢγ mRNA和蛋白的表达;最后,用1 μg/mL LPS处理IPEC-JⅡ细胞24 h,用实时荧光定量PCR和Western blotting检测p65、p38、JNK、ERK mRNA和蛋白表达及磷酸化水平。结果显示,除0.01 μg/mL LPS不抑制IPEC-JⅡ细胞活力外,其他浓度的灭活E.coli和LPS均可抑制IPEC-JⅡ细胞活力,且10⁹、10⁸ CFU/mL E.coli和10、20、40、80 μg/mL LPS组细胞活力极显著下降（P<0.01）;与对照组相比,10⁷、10⁶和10⁵ CFU/mL E.coli均能诱导RegⅢγ表达增加,且10⁵ CFU/mL E.coli组RegⅢγ mRNA表达量极显著高于对照组（P<0.01）,蛋白表达量显著高于对照组（P<0.05）;0.01、0.1、1和10 μg/mL LPS均能诱导RegⅢγ表达增加,且0.1和1 μg/mL LPS组RegⅢγ mRNA表达量极显著高于对照组（P<0.01）,RegⅢγ蛋白表达虽有增加趋势,但差异不显著（P>0.05）;与对照组相比,1 μg/mL LPS组p65、p38 mRNA表达量极显著增加（P<0.01）,JNK、ERK mRNA表达量显著增加（P<0.05）;同时,p38、JNK蛋白表达量和磷酸化水平均极显著增加（P<0.01）,p65蛋白磷酸化水平显著增加（P<0.05）,ERK蛋白和磷酸化水平均增加,但差异不显著（P>0.05）。以上结果表明,灭活E.coli和LPS均可诱导RegⅢγ表达,1 μg/mL LPS可增加p65、p38和JNK蛋白的磷酸化水平。     

新疆栽培与野生一枝蒿粗多糖对口蹄疫疫苗免疫小鼠的佐剂活性比较

基于总物质量和多糖含量比较栽培/野生一枝蒿粗多糖（cultivated/wild Artemisia rupestris L.crude polysaccharides,CARCP/WARCP）作为口蹄疫灭活疫苗（foot-and-mouth disease inactivated vaccine,FMDV）佐剂对小鼠抗体水平及T细胞亚群的影响,探究CARCP/WARCP的佐剂活性和安全性。CARCP/WARCP配伍FMDV肌肉途径免疫ICR小鼠,检测免疫后小鼠血清中FMDV特异性抗体及分型,脾中T细胞亚群比例,血清中IgE水平,观察临床症状和注射部位反应以及小鼠体重。结果显示,总物质量一致时,CARCP1/WARCP1均能极显著提高FMDV特异性IgG、IgG_2a反应（P<0.01）,极显著促进脾T细胞CD3⁺CD4⁺、CD4⁺CD44⁺、CD8⁺CD44⁺CD62L⁺百分比（P<0.05）,显著提高IgG₁、IgG_2a/IgG₁比值,显著促进CD3⁺CD8⁺、CD8⁺CD44⁺、CD8⁺CD44⁺CD62L^-比例（P<0.05）,且除28 d IgG和IgG₁指标外,CARCP1的佐剂活性显著高于WARCP1（P<0.05）。多糖含量一致时,与FMDV相比,CARCP2/WARCP2均极显著增强了28 d IgG水平、IgG_2a/IgG₁比值（P<0.01）,显著提高了21 d IgG、28 d IgG_2a及CD4⁺CD44⁺（P<0.05）,且CARCP2/WARCP2之间差异不显著（P>0.05）。CARCP/WARCP没有引起小鼠脱毛等临床症状,也没有产生肉芽肿、肿胀等注射部位不良反应;CARCP/WARCP免疫后各组小鼠体重之间差异不显著（P>0.05）;各组小鼠血清均没有检测到IgE抗体（P>0.05）;这些结果表明CARCP/WARCP有一定的安全性。综上,当总物质量一致时,CARCP/WARCP均能增强FMDV免疫小鼠体液和细胞免疫反应,且CARCP的佐剂活性优于WARCP;多糖含量一致时,CARCP/WARCP作为FMDV佐剂的免疫增强效果相当,是安全佐剂候选物。     

牦牛EPO、PPARα基因SNP与高原低氧适应的相关性分析

试验旨在探究促红细胞生成素基因（EPO）、过氧化物酶体增殖剂激活受体α（PPARα）的遗传多样性,并分析其多态性与牦牛高原低氧适应性的相关性。采集不同海拔高度的6个牦牛类群（中甸牦牛、麦洼牦牛、斯布牦牛、类乌齐牦牛、帕里牦牛、申扎牦牛）以及三江黄牛共375头耳样,提取DNA并分别构建DNA池,采用直接测序法结合PCR-RFLP检测分析EPO、PPARα基因的多态性,最后应用SHEsis软件统计分析候选基因SNPs与牦牛高原适应性的相关性。结果表明,EPO基因存在3个SNPs位点：rs527G→A、rs1031A→T、rs1192T→C;PPARα基因存在3个SNPs位点：rs77363C→T、rs77471C→A和rs77534C→T。χ²适合性检验结果显示,EPO基因3个SNPs位点均符合Hardy-Weinberg平衡状态;PPARα基因的rs77363C→T位点上,6个牦牛类群都处于平衡状态（P>0.05）,在PPARα基因的rs77471C→A和rs77534C→T位点,麦洼牦牛偏离Hardy-Weinberg平衡（P<0.05）。单倍型分析得出,EPO基因的ATC单倍型在高海拔地区牦牛中的分布频率随海拔升高而升高;PPARα基因的TAC单倍型在6个牦牛类群中分布频率显著高于其他单倍型。研究表明,EPO、PPARα基因可作为牦牛适应高原环境的分子标记,为进一步探讨牦牛高原低氧适应性机制提供一定理论帮助。     

Histological studies on the ontogeny of bovine palatine and pharyngeal tonsil: germinal center formation, IgG, and IgA mRNA expression

The development and distribution of lymphocyte subsets in calf palatine and pharyngeal tonsil were examined. During prenatal development, B cells were distributed in the subepithelial area, and T cells and MHC class II⁺ cells were found in the deep layer of B-cell area, respectively, in both tonsils. At neonatal stage, lymphoid follicle containing a few CD4⁺ cells have been formed in both tonsils. IgG⁺ and IgA⁺ cells were found in the parafollicular and epithelial area. At 3 months old, many germinal centers were recognized in both tonsils. CD4⁺ cells and IgG mRNA expression were detected in light zone of germinal centers. Many IgG, and IgA mRNA expressions also could be detected in the parafollicular and subepithelial area of both tonsils. The data suggest that both tonsils have an important role of local immune defense against invading antigen after birth. The comparison of the histological characteristics of tonsil and Peyer's patch during ontogeny is also discussed.     

Expression characteristics of immune factors in the yak (Bos grunniens) testis

The goal of this study was to characterize and evaluate the main markers of macrophages, T lymphocytes, B lymphocytes and plasmocytes in the testis of juvenile and adult yaks by quantitative real-time polymerase chain reaction and immunohistochemistry. Within the same age group, the mRNA expression of CD68 was always highest, followed by that of CD3ε, CD79α, IgG and IgA. Moreover, CD68, CD3, CD79α, IgA and IgG positive cells were all located in the testicular interstitial tissues of juvenile and adult yaks. In the same age group, the frequency of CD68 positive macrophages was higher than that of CD3 positive T lymphocytes, which was followed by that of CD79α positive B lymphocytes and IgA and IgG positive plasmocytes. No significant difference was observed between the B lymphocyte and plasmocyte frequencies in yak testes. Furthermore, CD68, CD3ε, CD79α, IgA and IgG mRNA expression levels and the frequencies of CD68, CD3, CD79α, IgA and IgG positive cells increased from juveniles to adults. Similarly, the frequencies of CD68, CD3, CD79α, IgA and IgG positive cells also increased with age. These results suggest that in the yak testis, the immune defence system against pathogens might primarily comprise macrophages and T lymphocytes in the testicular interstitial tissue. Moreover, the testicular immune environment may mature and expand to a fully functional state in adult yaks. The low frequencies of B lymphocyte and plasmocyte in yaks, differing from those in rodents and humans, might be related to the fact that yaks live in low-oxygen plateaus.     

白细胞介素-10对口蹄疫病毒感染小鼠T细胞增殖及其表达TNF-α、IFN-γ和IL-2的影响

白细胞介素-10(IL-10)增高是口蹄疫病毒(FMDV)感染过程中显著特征之一。本研究旨在探讨IL-10对FMDV感染小鼠外周血T细胞增殖及其表达效应功能相关细胞因子的影响。采用CCK-8和流式细胞术分别检测小鼠外周血T细胞增殖和T细胞表达效应功能相关细胞因子(TNF-α、IFN-γ和IL-2)。结果显示,与对照小鼠相比,FMDV感染小鼠(感染12、24、36和48 h)外周血T细胞对刀豆蛋白A刺激的增殖均显著下降(P<0.05或P<0.01);FMDV感染小鼠的外周血CD4⁺T细胞表达TNF-α和IL-2均显著下降(均P<0.01),CD8⁺T细胞表达TNF-α、IFN-γ和IL-2也显著下降(P<0.01或P<0.000 1)。体内阻断IL-10/IL-10R信号或者敲除IL-10均能显著恢复FMDV感染小鼠外周血T细胞的增殖(P<0.05或P<0.01),但不影响CD4⁺和CD8⁺T细胞表达TNF-α、IFN-γ和IL-2。本研究首次揭示FMDV能抑...     

Analysis of Immune Response Induced by Recombinant Lactobacillus reuteri Expressing Cap Protein of Porcine Circovirus Type 2 in Mice

The purpose of this study was to construct a recombinant Lactobacillus reuteri (L. reuteri) expressing the cap protein of porcine circovirus type 2 (PCV2) and evaluate its effect on immune response in mice. The cap protein gene of PCV2b strain isolated and stored in the laboratory was amplified by PCR. A recombinant strain pPG-T7 g10-PPT-cap / L. reuteri expressing the cap protein was constructed using L. reuteri of pig origin as the host strain and explored the immune effect of BALB/c mice with recombinant bacteria orogastrically. Indirect ELISA was used to determine the level of antigen-specific IgG antibodies in the serum of mice after immunization, the levels of antigen-specific sIgA antibodies in stool, nasal wash, reproductive tract wash, and intestinal mucus, and the levels of various cytokines in mouse serum; MTT method was used to detect mouse spleen lymphocyte proliferation levels; flow cytometry (FCM) was used to detect the levels of CD4⁺ T cells and CD8⁺ T cells in mouse spleen lymphocytes; fluorescence quantitative PCR was used to detect the viral load of organs in challenged mice after immunization. The results showed that the serum levels of IgG antibodies in the mice of the oral immune recombinant strain group (OIG) were significantly higher than those in the control group (P<0.01); the levels of sIgA antibodies in the stool, nasal wash, reproductive tract wash, and intestinal mucus of the mice in OIG were significantly higher than those in the control group (P<0.01); Compared with the control group, the levels of cytokines in the serum of OIG were as follows: The levels of IFN-γ, IL-2, IL-4, IL-12 increased, the levels of IL-10 decreased, and the levels of IFN-α did not change significantly; Incubation of PCV2 and mouse spleen lymphocytes in vitro showed that the proliferation stimulating index of spleen lymphocytes in OIG was significantly higher than that of the control group (P<0.01); FCM results showed that CD4⁺ T cells and CD8⁺ T cells were higher than those of the control group; the results of fluorescent quantitative PCR showed that compared with the control group, the viral load in the OIG was significantly lower than that of the control group. In summary, the recombinant L. reuteri expressing the PCV2 cap protein were successfully constructed, and the constructed recombinant L. reuteri can stimulate mice to produce humoral and cellular immune responses after oragastrical immunization, and can exert a certain immune protection effect.     

The Localization Changes of CD4+ and CD8+ T Lymphocytes in Chicken Lung at Different Ages

The aim of this study was to investigate the immune state of chicken lung in different periods.With lung tissue of Hy-line White chicken at different ages,the distribution and quantity changes of CD4⁺ and CD8⁺T lymphocytes in lung were studied using immunohistochemistry staining.The results showed that CD8⁺T lymphocytes appeared firstly in embryonic at 18 d,while CD4⁺T lymphocytes appeared at 1-day-old chicken.At 4-day-old,there were aggregates of lymphocytes at the junction of the primary and secondary bronchi,which formed obvious broncho-associated lymphoid tissue (BALT).CD4⁺T lymphocytes of each age mainly occupied the central area of BALT,while CD8⁺T lymphocytes mainly surrounded the periphery.Since 56 days old,CD8⁺T lymphocytes are distributed in the inner wall of third-order bronchial airway,atrial septum,gas exchange area and interlobular connective tissue,and are distributed throughout the lung.In terms of quantity change,with the growth of daily age,the number of CD4⁺T lymphocytes and CD8⁺T lymphocytes gradually increased,and the number of CD4⁺ T lymphocytes was more than that of CD8⁺ T lymphocytes before 35 days of age,while the number of CD8⁺ T lymphocytes was significantly more than that of CD4⁺ T lymphocytes at the same age thereafter.The results showed that the distribution and number of CD4⁺ and CD8⁺T lymphocytes in the lungs of chickens were correlated with the age,and the changes could reflect that the lungs before the age of 35 days were dominated by humoral immunity,while the lungs after that tended to be cellular immunity.