Pathogenicity and immunogenicity of three Mycoplasma gallisepticum isolates in house finches (Carpodacus mexicanus)

Mycoplasma gallisepticum (MG) has become a common cause of conjunctivitis in free-living house finches (Carpodacus mexicanus) since its emergence in the early 1990s. To date, temporal and spatial genotypic variation in MG has been documented, but phenotypic variation in pathogenicity and immunogenicity has not been examined. House finches were inoculated with MG isolates Virginia (VA)1994, California (CA)2006, or North Carolina (NC)2006, which were cultured from free-living house finches with conjunctivitis in 1994, 2006, and 2006, respectively. Infection with NC2006 resulted in the most severe eye lesions, highest pathogen loads, and highest levels of pathogen-specific lachrymal and serum antibodies. Infection with CA2006 caused the least severe eye lesions, lowest pathogen load, and lowest levels of antibodies. A small number of birds in each group developed protracted, severe disease in spite of robust antibody responses, suggesting that immunopathology may contribute to the lesions. Immunoblot analyses indicated that isolates are antigenically similar; thus, there may be partial cross-protection if a house finch encounters two or more strains of MG throughout the course of its lifetime. This study provides evidence that MG strains or strain variants circulating in house finch populations vary in their ability to cause disease, induce antibody responses, and persist in the host.     

Serum and Colostral Antibody Responses of Pregnant Mares to Salmonella Bacterins and Colostral Antibody Transfer to Their Foals

Salmonella spp. are well-recognized foal pathogens. However, prevention of neonatal salmonellosis by vaccinating pregnant mares has not been reported previously. A formalinized adjuvanted bacterin of Salmonella enterica, serovar typhimurium (S typhimurium) and serovar newport (S newport), was given to pregnant mares to determine its safety (study 1) and potency in enhancing Salmonella-specific antibody for colostral transfer to foals (study 2). Antibody levels to S typhimurium (lysate and lipopolysaccharide [LPS]) and S newport (lysate) were determined by enzyme-linked immunoassay and reported as optical density measures. The mares in study 1 (n = 16) exhibited minimal reactions to the bacterin, and pregnancy was maintained in all mares throughout the study period. In study 2, serum antibody levels to both S typhimurium and S newport increased significantly in vaccinated mares (mean OD increase: 0.83 ± 0.58 [lysate of S typhimurium], 1.27 ± 0.82 [LPS of S typhimurium], and 0.67 ± 0.74 [lysate of S newport], respectively; n = 28). Elevated serum antibody levels on day 28 correlated with high antibody levels in colostrum (r² = 0.62-0.75; P < .0001) and in serum samples of foals (r² = 0.5-0.73; P < .001).     

复方人参皂苷纳米乳对OVA接种小鼠免疫功能的影响

旨在研究口服复方人参皂苷纳米乳对抗原免疫效果的影响。将小鼠分为正常对照组、卵清白蛋白(OVA)对照组、空白纳米乳组、盐酸左旋咪唑纳米乳组、人参皂苷纳米乳组、人参皂苷-盐酸左旋咪唑水溶液组和复方人参皂苷纳米乳组(高、中、低剂量),皮下注射OVA抗原2次,在首次和第2次注射前3d连续灌胃给药,第2次注射后14d,测定血清(IgG、IgG1和IgG2a)抗体水平、脾细胞因子(IFN-γ和IL-4)水平以及脾淋巴细胞增殖刺激指数。结果表明,复方人参皂苷纳米乳中剂量(50mg·kg-1)组IL-4、IgG和IgG1水平显著或极显著高于复方人参皂苷纳米乳低剂量组和盐酸左旋咪唑纳米乳组,IFN-γ、IgG2a及OVA诱导脾淋巴细胞增殖刺激指数显著或极显著高于人参皂苷纳米乳组、人参皂苷-盐酸左旋咪唑水溶液组、盐酸左旋咪唑纳米乳组、复方人参皂苷纳米乳高剂量组和低剂量组。口服复方人参皂苷纳米乳能诱导OVA免疫小鼠产生Th1/Th2混合型免疫反应,表明人参皂苷和盐酸左旋咪唑能协同增强小鼠的细胞免疫和体液免疫功能。     

抗HepG2核糖体展示抗体库的构建

[目的]构建鼠源抗HepG2核糖体展示抗体库。[方法]以培养的HepG2肝癌细胞4次免疫Balb／c小鼠,取脾脏分离总RNA,逆转录合成第一条链,PCR扩增重链可变区和轻链k,经linkerDNA连接形成VH／k核糖体展示抗体库。将VH／k与pMD18-T载体的连接产物转化E．coliTGI,蓝白斑筛选,挑取白色菌落,提取质粒,PCR鉴定,并测序。[结果]VH和k链得到正确的扩增,长度分别为399和6476p,VH／k连接产物正确,连接产物长度为10936p：[结论]所采用的引物及反应条件能够扩增出目的基因,成功构建了鼠源抗Hepc2核糖体展示抗体库,为进行核糖体展示体外筛选抗HepG2特异性单链抗体奠定基础。     

A model to simulate the effect of vaccination against Boophilus ticks on cattle

In this study, serum antibodies to Sarcoptes scabiei var. canis (SS), Dermatophagoides farinae (DF), and D. pteronyssinus (DP) were determined in 19 healthy, random-source dogs prior to infestation with scabies then again during a primary infestation, cure and challenge infestation with scabies. Prior to scabies infestation, serum of 11 dogs contained faintly detectable amounts of IgE and/or IgG to proteins in SS extract, probably resulting from sensitization to dust mites that share cross-reactive antigenic epitopes with SS. After becoming infested with scabies, the response to SS antigens became stronger with antibodies appearing to more antigens as the scabies infestation progressed. Three of the newly recognized proteins were 170, 155 and 142/133 kD and could be used in a diagnostic test since antibodies to them appeared during the primary infestation.

In addition, during the primary infestation, 14 of 15 dogs developed IgE to 1–11 new SS proteins in addition to an increase in IgE binding to those proteins recognized prior to infestation. Overall, the strongest antibody responses (IgE and IgG) were exhibited during cure of the first infestation, when dead mites were still present in the stratum corneum. As expected, the antibody response was strong and rapid during challenge when the infestation self-cured. The immunogenic SS proteins identified by serum antibody binding during challenge, when the hosts self-cured, are candidates for inclusion in a vaccine. These candidate proteins are 200, 185, 170, 155, 142/133, 112, 97, 74, 57, 45/42, 32 and 22 kD.

Some of the proteins in SS that exhibited new or increased antibody binding during the experiment also had IgE and IgG binding to proteins with similar molecular weights in DF and DP extracts. These results illustrate the difficulties involved in understanding and interpreting serum antibody for developing a serological test for the diagnosis of scabies, isolating relevant SS antigens that could be included in a vaccine for prevention of scabies, and for understanding the immune response mechanism to scabies.     

抗兔瘟精制卵黄抗体的研制

选用免疫原性好的兔瘟抗原加工成浓缩兔瘟灭活组织疫苗,按特定的免疫程序接种健康商品鸡群,通过血凝抑制试验检测免疫鸡群血清和卵黄的兔瘟抗体效价,适时收集高免卵黄,选用特定的抗体分离提纯工艺,研制对兔瘟有预防和治疗双重作用的精制卵黄抗体。经实验室生物学检验,本品使用无刺激,作用迅速,对兔瘟早期治愈率为80%,对兔瘟紧急预防有效率为100%。     

Challenges for bovine viral diarrhoea virus antibody detection in bulk milk by antibody enzyme-linked immunosorbent assays due to changes in milk production levels

Background

Bovine viral diarrhoea (BVD) is considered eradicated from Denmark. Currently, very few (if any) Danish cattle herds could be infected with BVD virus (BVDV). The Danish antibody blocking enzyme-linked immunosorbent assay (ELISA) has been successfully used during the Danish BVD eradication program, initiated in 1994. During the last decade, the cattle herd size has increased while the prevalence of BVDV has decreased. In this study, we investigated how these changes could affect the performance of the Danish blocking ELISA and of the SVANOVIR^®BVDV-Ab indirect ELISA. The latter has successfully been used to eradicate BVD in Sweden.Data (2003–2010) on changes in median herd size and milk production levels, occurrence of viremic animals and bulk milk surveillance were analysed. Additionally, the Danish blocking ELISA and the SVANOVIR ELISA were compared analyzing milk and serum samples. The prevalence of antibody positive milking cows that could be detected by each test was estimated, by diluting positive individual milk samples and making artificial milk pools.

Results

During the study period, the median herd size increased from 74 (2003) to 127 cows (2010), while the prevalence of BVDV infected herds decreased from 0.51 to 0.02 %. The daily milk yield contribution of a single seropositive cow to the entire daily bulk milk was reduced from 1.61 % in 2003 to 0.95 % in 2010 due to the increased herd size. It was observed that antibody levels in bulk milk decreased at national level. Moreover, we found that when testing bulk milk, the SVANOVIR^®BVDV-Ab can detect a lower prevalence of seropositive lactating cows, compared to the Danish blocking ELISA (0.78 % vs. 50 %). Values in the SVANOVIR^®BVDV-Ab better relate to low concentrations of antibody positive milk (R² = 94-98 %), than values in the blocking ELISA (R² = 23–75 %). For sera, the two ELISAs performed equally well.

Conclusions

The SVANOVIR ELISA is recommended for analysis of bulk milk samples in the current Danish situation, since infected dairy herds e.g. due to import of infected cattle can be detected shortly after BVDV introduction, when only few lactating cows have seroconverted. In sera, the two ELISAs can be used interchangeably.     

Serological survey of Neospora caninum in dogs in the Czech Republic and a long-term study of dynamics of antibodies

The main aim of the present study was to establish the prevalence of antibodies against Neospora caninum dogs from the Czech Republic and to examine the dynamics of antibody titers during a long-term period. For this purpose, sera of 858 dogs were examined for the presence of anti-N. caninum antibodies using an indirect immunofluorescent antibody test (IFAT). Four groups of dogs of various origins were included in the survey: the first group (A, n=470) comprised dogs purchased by the Czech Army from the civilian sector throughout the Czech Republic, with 22 (4.7%) N. caninum-positive dogs, second group (B, n=115) represented police dogs with no seropositive animal, third group (C, n=195) were pet dog sera collected for veterinary clinic with 5 (2.6%) anti-N. caninum sera and the fourth group (D, n=78) of canine shelter dogs with the seroprevalence of 19.2%. The differences in seroprevalence were significant (P< or =0.01) between groups B and A, and between D and A. None of the serologically positive animals had clinical signs of neurological disorders. Coprological examination did not reveal any dog shedding N. caninum oocysts. The seropositivity rates for N. caninum were analyzed in relation to other data, such as age, breed and gender. Increased prevalence rates of anti-N. caninum antibodies were found in the older age strata of the dog population sample tested in the present study. We found significantly higher (P=0.02) prevalence in 3-3.5-year-old dogs (11.1% of 36), as compared to 1-1.5-years-old dogs (2% of 98). A longitudinal study of antibody dynamics was carried out in 19 initially seropositive dogs over a period of 4 years. The second and third examinations revealed that antibody titers decreased in majority of positive dogs (10, 52.6%), of which in seven cases (36.8%) the titers fell to levels that are currently considered as being seronegative (titer <1:50), or even became undetectable (titer <1:25).     

公牛的自身免疫反应与精液品质的关系

为了进一步了解公牛在自身免疫学反应中对其本身精液品质的影响,本试验应用Kibrick和F-D法分别测定了不同季节和不同年龄公牛血液中抗精子抗体效价及对精子的凝集度。在相同的饲养条件下4头同龄公牛血液中抗体效价和凝集度夏季高,冬季低。而精子顶体完整率则是夏季低,冬季高。从年龄上根据试验分析,老龄公牛血液中抗体效价和凝集度均高,青年公牛低,中年公牛介于中间,精液品质中的顶体完整率老龄牛最低（成不可逆的）,中年和青年公牛较高。     

“2+4”生产模式下种鸽新城疫免疫程序的初步确定

为建立肉鸽养殖"2+4"生产模式下种鸽新城疫人工免疫的方法,选择不同年龄的贝来得种鸽免疫接种新城疫灭活疫苗,通过血凝和血凝抑制试验检测了该灭活疫苗的抗体效价。结果发现,抗体水平都能维持250 d左右,而且抗体水平的消长规律与种鸽的年龄有关。