基因免疫的研究进展

综述了当前基因免疫的研究进展，其内容包括基因载体、基因免疫应答，基因免疫佐剂、病毒、细菌、寄生虫肿瘤病的基因免疫保护，基因免疫的安全性分析及应用前景。     

基因免疫疫苗研究进展（待续）

新型疫苗的研究对于动物疾病的防治有重大的经济价值，基因免疫疫苗作为第三代疫苗，其具备传统疫苗和基因免疫不可比拟的优点，能够诱导全方位的免疫反应且使用安全方便，开创了疫苗发展史上的新纪元。综述了基因疫苗研究新进展，讨论免疫作用机理。     

基因免疫与动物生殖

基因免疫核心是将外源基因组装到含有必要表达调控元件的真核质粒表达载体上，然后将重组的质粒导入动物体内，使外源基因在体内表达，从而激活机体的免疫系统，引发免疫反应的．是90年代初开始发展起来的一种新方法。基因疫苗因为制备简单以及良好持久的免疫反应性，便于保存等优点而受到普遍重视，目前已成为分子生物学研究的重点方向之一。本文对基因免疫的的作用机制、方法和基因免疫对动物的生殖影响作一综述。     

基因免疫与基因疫苗

基因免疫是九十年代初发展起来的新兴免疫学技术，它是将编码目的抗原的基因以重组表达载体的形式经各种基因转移途径转入机体细胞，借用容量主细胞表达加工合成抗原分子，以MHC～I或（和）MHC～II类分子抗原处理和输送途径将抗原信息递呈给T细胞和B细胞。全过程模拟了病毒自然感染提呈过程，既产生了体液免疫，又启动了细胞免疫，使得免疫效果极大的改善。因此，基因疫苗也被誉为第三次疫苗革命，它将成为我们今后预防疾病的重要武器。基因免疫的优点是毋庸置疑的，其化学结构是比蛋白质稳定得多的DNA，便于保存和运输，很适合做疫苗…     

基因免疫研究进展及其面临的问题

传统疫苗是基于抗原刺激机体产生特异性抗体的原理，这类疫苗绝大多数是激发机本的体注免疫，很难启动细胞免疫。而基因疫苗能模拟病毒自然感染原提呈的过程，使表达的抗原能在自然的形式被加以提呈给免疫系统，即能产生细胞免疫，又能产生体液免疫，此种免疫不受母液抗体的干扰。自１９９０年报道了其基因治疗研究以来，基因免疫在预防人类某些病毒性、细菌性、寄生虫性疾病等方面取得了突破性进展。笔者就基因免疫的原理、特点、研     

表达MDV—gB基因的重组鸡痘病毒免疫效果观察

将马立克氏病病毒（MDV）gB基因插入鸡痘病毒中，构建了含有MDV－gB基因的重组鸡痘病毒（rFPV)，用rFPV、火鸡疱疹病毒（HVT）冻干疫苗、rFPV HVT二联疫苗分别免疫1日龄AA肉用雏鸡，8日龄攻毒后观察免疫保护效果。结果表明，3种疫苗均诱导了免疫应答，免疫保护率分别为69％、69％和85％。该重组病毒疫苗的免疫效果与HVT疫苗的免疫效果相当，二者联用具有免疫协同作用。     

核酸疫苗研究进展(下)

Sato等报道，在质粒载体上引入大肠杆菌Amp^ 抗性基因(内含有6核苷酸片段的ISS免疫增强序列)，真皮免疫小鼠后ISS增强CTL和Th1细胞的免疫反应。有人提出利用含有病毒免疫原性基因的基因大片段进行基因免疫，以弥补单基因免疫活性的不足。将协同因子如IL-2、IL-12、TCA等的表达质粒与抗原表达质粒混合注射可使Th1型细胞免疫增强，而GMcsf能明显加强体液免疫，     

鹅Ⅰ型禽副黏病毒F基因重组质粒的构建及其DNA免疫

通过RT-PCR扩增出鹅Ⅰ型禽副黏病毒GPMV／QY97-1株F蛋白基因的cDNA，并将F基因cDNA克隆到含CMV启动子的pCI载体上，构建这一基因的真核表达质粒pC-GPMVF，以此质粒肌肉注射3周龄非免疫鸡，并分别于免疫后第2、4、6周通过ELISA方法检测抗体水平。结果证明，用重组质粒pC-GPMVF免疫鸡，能刺激机体产生抗Ⅰ型禽副黏病毒的特异性抗体和免疫应答。     

凋亡抑制基因免疫对小鼠生长的影响

小鼠经凋亡抑制基因免疫后，从3周龄到8周龄基因免疫组小鼠平均体重比对照组分别低0．48、1．18、1．16、1．35、0．99、0．85g。基因免疫后的头2周，小鼠生长速度明显低于对照组，且生长速度的差异随着免疫时间的增加而减小。这提示该基因与小鼠生长有关，如果用基因治疗方法增加凋亡抑制基因表达量，有可能增加小鼠生长速度。将凋亡抑制基因作为候选基因，研究它对家畜生长的遗传效应，对家畜繁育有重要的意义。     

鸡新城疫病毒F基因疫苗接种剂量的研究

本研究以新城疫病毒 Ｆ 基因的ｃ Ｄ Ｎ Ａ 与真核表达载体ｐｃ Ｄ Ｎ Ａ３ 重组，构建了新城疫病毒 Ｆ基因疫苗。采用不同剂量接种 Ｓ Ｐ Ｆ鸡后，通过抗体监测和强毒攻击试验，分析了其诱导的体液免疫应答及免疫保护作用。结果表明，接种剂量为１００μｇ、２００ μｇ 时，试验鸡在免疫后第 ２ 周出现较明显的抗体反应，接种剂量为 １０ μｇ 时抗体变化不明显。以标准强毒 Ｆ４８ Ｅ９ 攻击后，空白对照组及接种剂量为１０ μｇ 和１００ μｇ 组的鸡只全部发病死亡，未获得免疫保护；而２００ μｇ 组鸡只全部存活，获得完全免疫保护。表明基因免疫效果与接种的剂量有密切的关系。     

Cloning of fox (Vulpes vulpes) Il2, Il6, Il10 and IFNgamma and analysis of their expression by quantitative RT-PCR in fox PBMC after in vitro stimulation by Concanavalin A

The immune response in the fox (Vulpes vulpes), despite the success of the oral rabies vaccine is not well characterised, and specific immunological tools are needed. A quantitative RT-PCR using SyBR Green to investigate fox cytokine expression after antigen PBMC in vitro re-stimulation is presented here. First, we cloned by homology with dog cytokine sequences the fox IL2, IL6, IL10, IFNγ and a partial 18S sequence. Fox specific primers were then defined and used to set up a species-specific quantitative RT-PCR assay using SyBR Green and 18S housekeeping gene as internal standard. The technique was validated using total RNA from fox PBMC stimulated with a polyclonal activator, Concanavaline A.     

血细胞免疫研究进展

综述红细胞和白细胞免疫研究进展 ,对于进一步了解血细胞在正常的生理活动中和一些疾病的病理生理发展过程中的作用以及探讨血细胞的免疫调节机制有一定的启发。     

Protective immune responses induced by in ovo immunization with recombinant adenoviruses expressing spike (S1) glycoprotein of infectious bronchitis virus fused/co-administered with granulocyte-macrophage colony stimulating factor

Infectious bronchitis virus (IBV) causes tremendous economic losses associated with production inefficiencies and mortality in poultry industry worldwide. In the present report, the recombinant adenoviruses expressing chicken granulocyte-macrophage colony stimulating factor (GM-CSF) and S1 gene of nephropathogenic IBV were constructed and characterized. Then, the immunological efficacy and protection against homologous IBV challenge were assessed in specific pathogen free (SPF) chickens. The results showed that the chickens vaccinated in ovo with rAd-S1, rAd-GM-S1 (GM-CSF fused with S1 using glycine linkers) and rAd-GM-CSF plus rAd-S1 (co-administered) developed specific anti-IBV HI antibodies. Moreover, the fusion of the GM-CSF markedly increased spleen cell proliferation and IFN-γ production while mild increased in IL-4 production, which demonstrated the enhancement of cell-mediated immune responses. Following challenge with IBV, the chickens in the group vaccinated with rAd-S1 fused or co-administered with GM-CSF had fewer nephropathic lesions and showed 100% protection as compared to that of rAd-S1 alone which showed 70% protection. It indicated that the single dose in ovo vaccination of the GM-CSF fused or co-administered with S1 of IBV could enhance significantly the humoral, cellular immune responses and provide complete protection against nephropathogenic IBV challenge. This finding may provide basic information for effective in ovo vaccines design against IBV.     

Dairy herd health, impedance on six acupuncture points and immune response factors in milk: A pilot study

This study aimed to evaluate whether immunological parameters in milk and the impedance at 6 acupuncture points (APs) were related to herd health: good versus poor. The study used a purposively selected sample of 10 herds and in each herd 15 to 18 animals were observed. Statistical models at animal level included a random herd effect, with age and days in milk as covariates. The capacity for immune response was estimated through in vitro proliferation counts in medium, LPS, and ConA. At the right and left bladder meridians we measured impedance at 3 APs related to disease resistance. The energy balance at the onset of lactation and other parameters confirmed the classification in good and poor health herds. The immunological parameters in milk were not significantly related to health status, but LPS values of two herds with the apparent poorest health were consistently lower. The good health herds showed significantly lower impedance at all APs. Impedance values at APs correlated negatively with counts of LPS, indicating that good health animals had consistently higher counts of macrophages, i.e. better innate disease resistance. To confirm prospects of the parameters, we recommend repeating the study with a larger randomly selected sample.     

Effect of transgenic expression of porcine interleukin-6 gene and CpG sequences on immune responses of newborn piglets inoculated with Pseudorabies attenuated vaccine

Porcine interleukin-6 gene and CpG sequences were used as immunoadjuvants to enhance the immune responses of newborn piglets to Pseudorabies attenuated vaccine (PAV). The titer of specific antibodies to PAV, the proliferation of lymphocytes and induced IL-2 activities were all examined to identify the immune response of the piglets. The results showed that the immune responses with CpG ODN and porcine interleukin-6 gene were significantly stronger than routine immunities. The data suggests that porcine IL-6 and CpG motifs could be employed as effective immunoadjuvants to raise the humoral and cellular responses of newborn piglets to Pseudorabies attenuated vaccine.     

MHC及其在动物遗传与育种方面的应用

主要组织相容性复合体(Major histocompatibility complex,MHC)不仅与移植排斥反应有关,而且还与动物的一些经济性状密切相关。文章主要阐述了MHC的结构、功能和遗传特性,并且介绍了MHC基因作为遗传标记在动物遗传与育种方面的应用。     

锌对动物免疫功能的作用效应

综述锌对畜禽、实验动物和人类免疫器官产生的不同效应及对免疫反应调节的环节、部位、方式，并提出了在未来研究中应当注意的一些重要问题。     

Lentivirus-induced immune dysregulation

FIV/HIV infections are associated with an early robust humoral and cellular anti-viral immune response followed by a progressive immune suppression that eventually results in AIDS. Several mechanisms responsible for this immune dysfunction have been proposed including cytokine dysregulation, immunologic anergy and apoptosis, and inappropriate activation of immune regulatory cells. Studies on FIV infection provide evidence for all three. Cytokine alterations include decreases in IL2 and IL12 production and increases in IFNγ and IL10 in FIV⁺ cats compared to normal cats. The elevated IL10:IL12 ratio is associated with the inability of FIV⁺ cats to mount a successful immune response to secondary pathogens. Additionally, chronic antigenic (FIV) stimulation results in an increase in the percent of activated T cells expressing B7 and CTLA4 co-stimulatory molecules in infected cats. The expression of these molecules is associated with T cells that are undergoing apoptosis in the lymph nodes. As ligation of CTLA4 by B7 transduces a signal for induction of anergy, one can speculate that the activated T cells are capable of T cell–T cell interactions resulting in anergy and apoptosis. The inability of CD4⁺ cells from FIV⁺ cats to produce IL2 in response to recall antigens and the gradual loss of CD4⁺ cell numbers could be due to B7–CTLA4 interactions. The chronic antigenemia may also lead to activation of CD4⁺CD25⁺ T regulatory cells. Treg cells from FIV⁺ cats are chronically activated and inhibit the mitogen-induced proliferative response of CD4⁺CD25⁻ by down-regulating IL2 production. Although Treg cell activation can be antigen-specific, the suppressor function is not, and thus activated Treg cells would suppress responses to secondary pathogens as well as to FIV. Concomitant with the well-known virus-induced immune suppression is a progressive immune hyper-activation. Evidence for immune hyper-activation includes polyclonal B cell responses, gradual replacement of naïve CD4⁺ and CD8⁺ T cell phenotypes with activation phenotypes (CD62L⁻, B7⁺, CTLA4⁺), and the chronic activation of CD4⁺CD25⁺ Treg cells. Thus lentivirus infections lead to severe immune dysregulation manifested as both chronic immune suppression and chronic immune activation. FIV infection of cats provides a number of advantages over other lentivirus infections as a model to study this immune dysregulation. It is a natural infection that has existed in balance with the cat's immune system for thousands of years. As such, the natural history and pathogenesis provides an excellent model to study the long-term relationships between AIDS lentivirus and host immune system function/dysregulation.     

Immunological variation between inbred laboratory mouse strains: points to consider in phenotyping genetically immunomodified mice

Inbred laboratory mouse strains are highly divergent in their immune response patterns as a result of genetic mutations and polymorphisms. The generation of genetically engineered mice (GEM) has, in the past, used embryonic stem (ES) cells for gene targeting from various 129 substrains followed by backcrossing into more fecund mouse strains. Although common inbred mice are considered "immune competent," many have variations in their immune system-some of which have been described-that may affect the phenotype. Recognition of these immune variations among commonly used inbred mouse strains is essential for the accurate interpretation of expected phenotypes or those that may arise unexpectedly. In GEM developed to study specific components of the immune system, accurate evaluation of immune responses must take into consideration not only the gene of interest but also how the background strain and microbial milieu contribute to the manifestation of findings in these mice. This article discusses points to consider regarding immunological differences between the common inbred laboratory mouse strains, particularly in their use as background strains in GEM.