Assessment of the safety and immunogenicity of Rhodococcus equi-secreted proteins combined with either a liquid nanoparticle (IMS 3012) or a polymeric (PET GEL A) water-based adjuvant in adult horses and foals—Identification of promising new candidate antigens

Rhodococcus equi is the most common infectious cause of mortality in foals between 1 and 6 months of age. Because of an increase in the number of antibiotic-resistant strains, the optimization of a prophylactic strategy is a key factor in the comprehensive management of R. equi pneumonia.The objectives of this study were to assess the safety and immunogenicity of R. equi-secreted proteins (ReSP) co-administered with either the nanoparticular adjuvant Montanide? IMS 3012 VG, or a new polymeric adjuvant Montanide? PET GEL A, and to further investigate the most immunogenic proteins for subsequent immunization/challenge experiments in the development of a vaccine against rhodoccocal pneumonia. The approach involved two phases. The first phase aimed to investigate the safety of vaccination in six adult horses. The second phase aimed to determine the safety and immunogenicity of vaccination in twelve 3-week-old foals.We set out to develop a method based on ultrasound measurements for safety assessment in adult horses in order to evaluate any in situ changes at the injection site, in the skin or the underlying muscle, with quantitative and qualitative data revealing that administration of ReSP combined with the Pet Gel A adjuvant led to an increase in local inflammation, associated with 4- to 7-fold higher levels of anti-R. equi IgGa, IgGb and IgGT, compared to administration of ReSP associated with IMS 3012 adjuvant, but without any impact on animal demeanor. Investigations were then performed in foals with serological and clinical follow-up until 6 months of age. Interestingly, we observed in foals a much lower incidence of adverse local tissue reactions at the injection site than in adult horses, with transient and moderate swelling for the group that received ReSP combined with Pet Gel A. Immunized foals with Pet Gel A adjuvant exhibited a similar response in both IgGa and IgGT levels, but a lower response in IgGb levels, compared to adult horses, with a subisotype profile that may however reflect a bias favorable to R. equi resistance. From the crude extract of secreted proteins, dot-blot screening enabled identification of cholesterol oxidase, mycolyl transferase 3, and PSP (probable secreted protein) as the most immunogenic candidates. Taken together, these results are encouraging in developing a vaccine for foals.     

转移因子对鸡传染性喉气管炎灭活疫苗作用的研究

用ILT油乳剂灭活疫苗免疫雏鸡和蛋鸡,同时实验组肌注TF,于免疫后不同时间用ILT种毒攻击,并测定蛋鸡的淋巴细胞转化率。结果试验组于免疫后第5d产生保护力,第9d产生全保护(对照组分别为7d和11d),雏鸡和蛋鸡的保护期可达90d及180d,蛋鸡免疫后7d的淋巴细胞转化率达高峰48.7%,而对照组的为14d和38.5%,90d时分别为36.3%和28.5%。表明TF能提高ILT灭活疫苗的免疫效果,提高蛋鸡的细胞免疫机能,经统计学检验,对雏鸡免疫保护力无显著差异,而蛋鸡的差异显著(P<0.05)。     

植物基因工程疫苗研究进展与前景展望

可口服免疫(oralimmunization)绿色疫苗(greenvaccine)研究是植物基因工程与分子医学相结合而发展起来的新的研究方向。对当前植物基因工程疫苗的研究方法、疫苗的作用机理进行介绍,总结近10年来国内外植物基因工程疫苗研究进展,并对未来发展做出展望。     

大肠杆菌耐热性肠毒素Ⅰ融合基因的构建及其免疫原性研究

用限制性核酸内切酶ＢａｍＨＩ和Ｂｇ１Ⅱ双酶切质粒ｐＢＳＴ２－６，获得了大肠杆菌耐热性肠毒素Ⅰ（ＳＴ１）基因，再将含ＬａｃＺ基因（编码β－半乳糖苷酶）的载体ｐＵＣ１８用ＢａｍＨＩ酶切、碱性磷酸酶处理，然后与ＳＴ１基因通过Ｔ４ＤＮＡ连接酶连接，转化至受体菌ＤＨ５α中。通过菌落原位杂交筛选，共筛选出５３个ＳＴ１基因探针杂交阳性的重组子，对其中一个重组子ＤＨ５α（ｐＸＳＴ１）进行限制性核酸内切酶酶切分析和核苷酸序列分析，证明重组质粒ｐＸＳＴ１含有２个正向串连在一起的ＳＴ１基因，而且融合在ＬａｃＺ基因的上游，具有正确的阅读框架。又ＤＨ５α（ｐＸＳＴ１）菌株能在含Ｘ－Ｇａｌ的ＬＢ平板上长成蓝色菌落，而且ＥＬＩＳＡ也检测到ＳＴ１融合蛋白，这表明该菌株能表达具有β－半乳糖苷酶活性的大肠杆菌ＳＴ１—β－半乳糖苷酶融合蛋白。免疫实验结果表明，重组菌株ＤＨ５α（ｐＸＳＴ１）安全无毒，表达的ＳＴ１融合蛋白能够诱发ＢＡＬＢ／ｃ鼠产生抗体，该抗体具有中和天然ＳＴ１肠毒素的毒性作用，这表明ＤＨ５α（ｐＸＴ１）可以作为预防幼畜腹泻的菌苗候选株。     

Effects of immunization of Pelibuey lambs with Oestrus ovis digestive tract protein extracts on larval establishment and development

Larval midgut proteins of hematophagous parasites contain strong antigens that can be used for host immunization. This concept has been applied for immunization of Pelibuey sheep against Oestrus ovis L. (Diptera: Oestridae). The aim of this study was to examine the effect of immunization on larval establishment (LE) and development. Immunized lambs (I, n = 6) received two injections of crude gut membrane protein extracts (GMPE) from third instar larvae with Freund's incomplete adjuvant (FIA) on days 0 (Day of first immunization) and 21 (0.4 and 0.45 mg GMPE/lamb, respectively). The control group (C, n = 5) received physiological saline with FIA. Lambs were challenged with first instars on Day 29 (20 larvae) and Day 43 (25 larvae). Blood samples were collected biweekly and IgG titers were analyzed by ELISA. All lambs were slaughtered on Day 90 and number of larvae recovered, larval stage and larval weight were recorded at necropsy. No significant effect of immunization on LE (C = 28.9%; I = 31.0% P > 0.05) was observed. Antibody titers were higher in the immunized group on Day 28 (P < 0.05), but subsequently similar in both groups. Larval physiological age and weight were also significantly (P < 0.05) affected by immunization. Immunization of Pelibuey lambs with GMPE did not affect LE but did delay O. ovis larval development.     

Lambs immunized with an inactivated variant of Anaplasma phagocytophilum

Background

Anaplasma phagocytophilum (formerly Ehrlichia phagocytophila) is an obligate intracellular bacterium causing the disease tick-borne fever (TBF) in domestic ruminants. An effective vaccine against the infection has been demanded for livestock by sheep farmers and veterinary practitioners for years.

Findings

In the present study, we immunized lambs with an inactivated suspension of 1 × 10⁸ killed A. phagocytophilum organisms mixed with adjuvant (Montanide ISA 61VG; Seppic). Twelve 9-months-old lambs of the Norwegian White Sheep breed were used. A full two-dose series of immunization was given subcutaneously to six lambs with a 4 week interval between injections. One month after the last immunization, all lambs were challenged with the homologous viable variant of A. phagocytophilum. After challenge, all lambs showed clinical responses for several days, although the immunized lambs reacted with an anamnestic response, i.e. significant reduction in infection rate and a significantly higher antibody titer.

Conclusion

Immunization with inactivated A. phagocytophilum did not protect lambs TBF.     

垫料管理对毒害艾美耳球虫疫苗虫株免疫效果的影响

为比较垫料管理对毒害艾美耳球虫疫苗虫株免疫效果的影响,采用谷壳和木屑为垫料,垫料厚度分别为1、2、4 cm,以及定期翻动垫料和不翻动垫料的管理方式对疫苗反应期鸡肠道病变程度和相对增重的影响,以及对攻虫后鸡肠道病变程度、相对增重和免疫保护效果的影响。在疫苗反应期,各免疫组的肠道病变轻微,相对增重与空白对照组无显著差异(P0.05);免疫21 d后攻虫,所有免疫组均能抵抗1×105个毒害艾美耳球虫强毒孢子化卵囊的攻击,而且肠道病变轻微,相对增重与空白对照组无显著差异(P0.05)。试验结果表明,厚垫料可提高毒害艾美耳球虫的免疫均匀性,免疫效果稍优于薄垫料。     

诺氟沙星多克隆抗体的制备

用合成的NFLX-BSA偶联物免疫成年獭兔,采用ELISA方法检测抗血清效价.结果表明:采用合成的NFLX-BSA偶联物免疫成年獭兔获得了高效价的抗血清.     

脂肪细胞膜免疫技术的研究进展

综述了脂肪细胞膜免疫的种类及其降低动物胴体脂肪的作用机理和效果,阐述了目前存在的问题,并展望了脂肪细胞膜免疫技术的应用前景。     

猪旋毛虫病疫苗后海穴免疫研究

本项目对猪旋毛虫病成虫可溶性抗原疫苗经后海穴免疫注射的效果进行了研究。大鼠经口感染旋毛虫肌幼虫后３或７ｄ剖杀，收集成虫。经超声粉碎、高速离心制备成虫可溶性抗原。将抗原与等体积ＦＣＡ乳化，按０．２５ｍｇ／头及０．５０ｍｇ／头的抗原量分别进行后海穴注射（ＡＰ）及腹腔注射（ＩＰ），免疫猪只，使之经受旋毛虫的实验室攻击感染及自然感染。结果表明，３日龄及７日龄成虫可溶性抗原的免疫原性基本一致。采用后海穴注射疫苗具有减少抗原用量、增强免疫效果的作用。免疫后猪血清抗体滴度增加，呈暂时的细胞免疫抑制现象。后海穴注射疫苗猪群保护率达１００％，增加一倍抗原量经腹腔注射的猪群保护率为７５．２６％。