不同来源禽网状内皮增生病病毒株的致病性比较

本研究旨在探讨不同来源的禽网状内皮增生病病毒(REV)对1日龄SPF鸡的致病性.用包括分子克隆化病毒REV-C99在内的不同来源的6个REV株人工感染1日龄SPF鸡,以禽流感病毒灭活疫苗(H9-AIV、H5-AIV)与新城疫病毒灭活疫苗(NDV)免疫后HI抗体滴度的测定结果为指标,比较不同REV株的致病性.结果表明,分别用3000TCID_(50)·只~(-1)的剂量人工感染1日龄SPF鸡,6个REV感染组与对照组相比,H9-AIV、H5-AIV与NDV免疫后4、5与6周的HI抗体水平均极显著降低(P<0.01).但6个REV感染组之间差异不显著(P>0.05).研究结果显示,不同来源REV株感染1日龄SPF鸡后均造成生长迟缓,并对体液免疫反应有明显的抑制作用,同时,这也揭示出REV感染可能是免疫失败的重要原因之一.     

五加芪水煎液对小鼠免疫功能的影响

旨在研究五加芪水煎液对小鼠免疫功能的影响。将6周龄雌性昆明小鼠随机分成正常小鼠组(正常对照,高、中、低剂量组)和免疫抑制小鼠组(正常对照,Hy+蒸馏水组,Hy+高剂量组,Hy+中剂量组,Hy+低剂量组),连续灌胃7d,测定小鼠免疫器官指数、碳粒廓清指数、血清溶血素水平和脾内抗体形成细胞(PFC)的变化。结果表明,高、中剂量五加芪水煎液可显著提高正常小鼠脾指数(P0.01),各给药组均能显著提高正常小鼠胸腺指数(P0.01或P0.05)和碳粒廓清指数(P0.01),高剂量五加芪水煎液能显著提高正常小鼠血清溶血素水平(P0.01),各给药组均对正常小鼠脾内抗体形成细胞数量无明显影响(P0.05)。各剂量五加芪水煎液均使免疫抑制小鼠脾指数、胸腺指数、碳粒廓清指数、血清溶血素水平和脾内抗体形成细胞数量显著提高(与Hy+蒸馏水组相比,P0.01或P0.05),且恢复至正常水平(与正常组相比,P0.05)。     

鸡传染性贫血病毒诱导细胞凋亡的研究进展

鸡传染性贫血病毒是鸡传染性贫血病的病原体,能引起雏鸡贫血、淋巴组织萎缩、出血及免疫抑制,是导致许多疫苗免疫失败及雏鸡死亡的主要原因之一。该病毒在世界范围内广泛存在,是养鸡业潜在的巨大威胁。近年来的研究表明,鸡传染性贫血病毒主要是通过其编码的凋亡素诱导雏鸡胸腺和骨髓中的造血祖细胞凋亡而致病的,而凋亡素诱导细胞凋亡的能力与其在细胞中的核定位及半胱氨酸蛋白酶(caspase)等因素密切有关。文章就鸡传染性贫血病毒生物学特征、诱导细胞凋亡的现象及机制的研究进行了综述。     

兽医中药免疫调节剂研究概况

中药免疫调节剂由具有免疫调节作用的中药及方剂组成,主要作用是调整机体过高或过低的免疫状态,使免疫系统的功能趋于正常.近年来由于动物疾病越来越复杂,免疫抑制性疾病的发生越来越普遍,所以兽医中药免疫调节剂方面的研究与应用日渐广泛.本文概述了免疫调节剂的概念、分类、适用范围、使用要求、作用原理,特别是重点综述了具有免疫调节作用的中药及方剂及其现代药理学研究、兽用中药免疫调节剂的研究情况及存在的问题等.     

Ochratoxin A as a suppressor of mitogen-induced blastogenesis of porcine blood lymphocytes

The in vitro effect of ochratoxin A on pig lymphocytes stimulated by the mitogen Concanavalin A was studied by measuring the rates of ³H-thymidine incorporation in DNA.Ochratoxin A inhibited the mitogenic response to Concanavalin A in a dose dependent way. An almost total inhibition was obtained with ≥ 1 mg ochratoxin A/1, approximately 60 % inhibition was produced by 0.5 mg ochratoxin A/1 and approximately 10 % inhibition by 0.06 mg ochratoxin A/1.The immunosuppressive effect of ochratoxin A was not altered much by different contents of bovine serum albumin, 0.1 or 0.3 %, in the cell culture medium.     

Suppression of testicular function using two dose rates of a reversible water soluble gonadotrophin releasing hormone (GnRH) vaccine in colts

Objective: To investigate the effect of two dose rates (200 and 400 ng) of a gonadotrophin releasing hormone (GnRH) vaccine on testicular function. Design: A vaccination dose rate experiment. Procedure: Two injections were administered 4 weeks apart to six colts in each treatment group. To maintain immunosuppression until the end of the breeding season, a third injection was given if antibody titres fell below 1000. Results: Effective antibody titres were present for 12 to 27 weeks. Testosterone concentrations decreased from 2.22 to 0.31 nmol/L 6 weeks after primary vaccination. Androstenedione concentrations decreased from 1.78 to 0.28 nmol/L 5 weeks after vaccination. Testosterone and androstenedione concentrations above 0.69 and 0.87 nmol/L were attained 31 to 43 weeks after vaccination. Mean scrotal widths and lengths decreased over 29 weeks from 9.2 cm and 9.7 cm to 6.7 cm and 7.6 cm. At surgical castration these dimensions were 10.1 cm and 11.0 cm. Mean semen characteristics before vaccination and after recovery were: gel-free volume 16.5 and 13.5 mL, sperm concentration 295.5 times 10⁶ 315.6 times 10⁶/mL, total sperm per ejaculate 4041 times 10⁶ 4657 times 10⁶ live normal spermatozoa 32% and 60%. Histologically, the testes showed active spermatogenesis. The mean testicular parenchyma weights for the 200 and 400 mg groups were 129.0 g and 109.8 g. Daily sperm production per testis and per gram of testis for the 200 and 400 mg groups were 3.7 times 10⁸ 2.8 times 10⁶ 2.3 times 10⁸ 2.0 times 10⁶. Conclusions: Both dose rates suppressed testicular function. Data showed that the vaccine effects were reversible. Individual immune response was less varied in the 200 mg group. Further work is necessary to achieve a less variable response in the immunosuppression of testicular function.     

Inhibition of in vitro lymphocyte blastogenesis by chicken alpha-fetoprotein

Chicken alpha-fetoprotein (ch-AFP), purified from fetal chicken serum and embryo extracts, respectively, was examined for its immunomodulatory effect in vitro. Significant (P less than 0.05) suppression of the allogeneic mixed lymphocyte reaction (MLR) was observed, when these preparations were added to one-way mixed lymphocyte cultures (MLC) in quantities of 62.5-1000 micrograms/ml. Suppression of the MLR was depending on the presence of ch-AFP for at least 16 h after initiation of the MLC, suggesting that this fetal protein was acting mainly in the early phase of lymphoblastogenesis. Serum of chicken embryos (12th and 15th day of incubation), day-old chickens, and of 10-week-old chickens of four different inbred lines were also found to exert suppression of the MLR. From these data, it is hypothesized that ch-AFP plays an immunoregulatory role by maintaining a certain stage of self tolerance during differentiation of the avian immune system.     

枣多糖对免疫抑制蛋雏鸡生长性能和免疫指标的影响

为探究金丝小枣多糖（ZJP）对免疫抑制蛋雏鸡生长性能和免疫指标的影响,本试验将900只健康且体重相近的1日龄京红1号蛋鸡随机分为6组,每组6个重复,每个重复25只鸡。Ⅰ组为空白对照组,饲喂基础饲粮;Ⅱ~Ⅵ组在7~9日龄时注射100 mg/kg体重的环磷酰胺,每天1次,建立免疫抑制模型,并分别在基础饲粮中加入600 mg/kg黄芪多糖（APS）及0、400、800和1 600 mg/kg ZJP。试验期为6周。结果显示,ZJP可在不同程度上显著缓解环磷酰胺导致的42日龄体重、22~42和1~42日龄的平均日增重、胸腺和法氏囊指数、聚合免疫球蛋白受体、分泌型免疫球蛋白A （sIgA）及血清中免疫球蛋白A （IgA）和IgG的降低及22~42日龄料重比（F/G）的升高,并且料重比、IgA和IgG达到了APS组的水平。由此得出,在本试验条件下,在基础饲粮中添加适宜水平的ZJP可不同程度改善环磷酰胺所致的生长缓慢和免疫功能低下。     

Cytologic diagnosis of generalized cutaneous sporotrichosis in a hunting hound

A 1-year-old male Foxhound/Walker Hound mix was presented to the small animal internal medicine service at Louisiana State University School of Veterinary Medicine with a 6-week history of progressive, multifocal, ulcerative and draining, well-circumscribed lesions in a generalized distribution. Prior to referral, a presumptive diagnosis was made of sterile pyogranulomatous disease; immunosuppressive therapy was instituted but resulted in clinical deterioration. At presentation, the dog had marked neutropenia (1100 neutrophils/microL), and a mild toxic left shift (400 bands/microL). Cytologic findings in the exudates from a draining skin lesion included high numbers of markedly degenerate neutrophils (about 95% of nucleated cells) as well as low numbers of macrophages, small mature lymphocytes, and eosinophils. Low numbers of intracellular (within neutrophils and macrophages) and extracellular, pleomorphic, cigar-to-ovoid shaped organisms ( approximately 3x9 microm) consistent with Sporothrix were observed. Histopathologic examination of a skin biopsy showed marked, chronic, active, ulcerative, pyogranulomatous dermatitis and panniculitis, with intralesional yeast consistent with Sporothrix sp. The etiologic agent was confirmed as Sporothrix schenckii by macerated tissue fungal culture. The patient was treated with itraconazole, enrofloxacin, and clindamycin, with clinical resolution occurring over a 3-month period. This case is a rare example of the cytologic diagnosis of Sporothrix schenckii in a canine patient. Diagnosis of canine sporotrichosis is often challenging and usually requires tissue culture, as infected dogs typically harbor very few organisms. The patient's prior immunosuppressive therapy likely contributed to higher numbers of organisms in exudates from the cutaneous lesions, facilitating cytologic diagnosis.