Duration of immunity induced by an adjuvanted and inactivated equine influenza, tetanus and equine herpesvirus 1 and 4 combination vaccine

An adjuvanted vaccine containing inactivated equine influenza, herpesvirus antigens, and tetanus toxoid was administered to young seronegative foals of 8 months of age by deep intramuscular injection in the neck (Group A). The first two vaccinations were given 4 weeks apart. The third was administered 6 months later. Another group of foals (Group B) was vaccinated according to the same scheme at the same time with monovalent equine herpes virus (EHV) vaccine (EHV1.4) vaccine. Antibody responses to the equine influenza (single radial haemolysis; SRH) and tetanus (ToBi ELISA) components of the vaccines were examined from first vaccination until 1 year after the third vaccination. The influenza components of the combination vaccine induced high antibody titres at two weeks after the second vaccination whereafter titres declined until the time of the third vaccination. After the third vaccination, the titres rose rapidly again to remain high for at least 1 year. Antibody titres against tetanus peaked only after the third vaccination but remained high enough to offer protective immunity for at least 1 year. Foals vaccinated with monovalent EHV1.4 remained seronegative for influenza and tetanus throughout the study. Four and a half months after the third vaccination of groups A and B, a third group of animals was vaccinated twice with monovalent EHV1.4 vaccine 4 weeks apart (Group C). Two weeks after the administration of the second dose in the later group, all groups (A, B, C and an unvaccinated control group D) were challenged with EHV-4. Vaccinated foals (Group A, B, C) showed a clear reduction of clinical symptoms and virus excretion after EHV-4 challenge compared with the unvaccinated control foals. No difference could be demonstrated among the vaccinated groups, suggesting that the combination vaccine protects as well as the monovalent vaccine. In EHV1.4-vaccinated foals both antigenic fractions induced clear protection up to 6 months after vaccination (9). It can therefore be anticipated that the efficacy of the combination vaccine against EHV-1 challenge is similar to the efficacy against EHV-1 induced by EHV1.4 vaccination.     

Immunostimulatory properties of a novel adjuvant administered with inactivated influenza virus vaccine

The immunopotentiating activity of a new delivery system was investigated comparatively to Alhydrogel adjuvant, as an antiviral inactivated vaccine after one injection. The efficiency of the new formulation (BioMed) was evaluated with an inactivated porcine strain of influenza (A/Sw/IN/1726/88 H1N1) in the pig model. The first assessment criteria was the follow-up of selected immunological parameters such as, antibody levels, lymphoproliferation, double positive CD4+CD8+ T lymphocytes and cytokine production (IL-2, IL-4, IFN-gamma). The second criteria was the estimate of the protection level of animals exposed to a homologous challenge of 50 PID50 one month after a single immunizing or control injection. In the BioMed group of animals, 4 pigs (out of 6) were free of macroscopic lesion, while lesions could be seen in all individuals of other groups and virus was isolated in only one animal, whereas all other animals of other groups had virus in their lungs. This better protection of BioMed animals seems to be correlated mainly with higher levels of antibodies and to a lesser extent with a slightly better CMI response and probably with the production of memory CD4+CD8+ T cells.     

Risk factors for equine influenza serum antibody titres in young thoroughbred racehorses given an inactivated vaccine

Young Thoroughbred racehorses (222 yearlings entering training and 246 2-year-old horses already in training) from eight flat-training yards in Newmarket, UK were used to monitor serological responses to vaccination with an inactivated influenza virus vaccine. Blood samples taken prior to and after vaccination were tested by single radial haemolysis (SRH) to determine antibody titres (expressed as area of haemolysis in mm(2)). Prior to vaccination, yearlings had mean antibody titres (64+/-4 mm(2)) that were approximately half of those of 2-year-olds (115+/-3 mm(2)) and 89% of yearlings and 73% of 2-year-olds had SRH titres <140 mm(2). Extrapolation from experimental and field studies suggests that these levels would not protect against homologous influenza virus infection. Both age-groups showed anamnestic responses to vaccination resulting in similar peak mean titres ( approximately 160+/-2mm(2)) with 67% of yearlings and 73% of 2-year-olds achieving levels > or =140 mm(2). A second dose of vaccine administered a month after the first in yearlings did not increase the mean titre but 75% of horses had levels of antibody > or =140 mm(2). The vaccination history in the official passport of yearlings showed that 23% had no record of previous vaccination and were probably fully susceptible to infection. For yearlings entering training, the important predictors from multiple-regression analyses of SRH titres prior to vaccination were "Time since last vaccination," "Total number of previous vaccines" and "Age at first vaccination." In 2-year-olds and following two doses of vaccine in yearlings, there was no significant relationship between these factors and SRH titre.     

鸭疫里默氏菌1,2,4和5型铝胶复合佐剂四价灭活疫苗的研究

选择了流行最为广泛的血清 1,2 ,4和 5型鸭疫里默氏菌 (RA)制备四价铝胶复合佐剂灭活苗 ,经过无菌及安全检查合格后 ,3日龄樱桃谷鸭颈背皮下注射 0 .5mL/只。免疫后 10 ,13和 16天对同源RA的攻击表现出 10 %～ 35 %、80 %～ 10 0 %和 10 0 %免疫保护 ,5 1～ 6 5d免疫保护力开始下降。疫苗一次免疫后 2 3d抗体水平均达到高峰 ,至 93日龄时仍能检出抗体 ,10日龄进行二次免疫后可产生更高的抗体水平 ,到 6 5d时仍能保持较高抗体水平。疫苗免疫雏鸭后能够显著 (P <0 .0 5 )或极显著 (P <0 .0 1)地增强T细胞的免疫力 ,时间达 2 2周。对攻毒保护试验、抗体消长规律、细胞免疫测定和田间试验结果综合分析表明 ,RA四价铝胶复合佐剂灭活苗免疫雏鸭后免疫保护的形成是体液免疫与细胞免疫协同作用的结果 ,疫苗均具有良好的安全性和免疫原性 ,为生产中有效预防该病的发生提供了良好的疫苗     

蜂胶对猪细小病毒灭活疫苗佐剂作用的试验

68只豚鼠随机均分为4组,1³组分别免疫蜂胶、铝胶和油佐剂PPV疫苗,第4组为空白对照组,注射等量生理盐水。免疫后不同时间点采集血清分析特异性血凝抑制抗体效价评价蜂胶佐剂对免疫豚鼠体液免疫的影响,测定淋巴细胞增殖、IL-2和IL-4含量评价蜂胶佐剂对免疫豚鼠细胞免疫的影响。结果表明,蜂胶、油佐剂和铝胶3种佐剂均能提高豚鼠对PPV灭活疫苗的免疫应答能力,油佐剂提高血清HI抗体效果较好,其次为蜂胶佐剂,再次为铝胶佐剂。蜂胶佐剂促进T淋巴细胞增殖和提高IL-2、IL-4、IL-6和IFN-γ含量效果优于油佐剂和铝胶佐剂。结论:蜂胶能增强PPV灭活疫苗的免疫效果。     

副猪嗜血杆菌灭活疫苗佐剂的筛选

为了评价铝胶、蜂胶及白油佐剂对副猪嗜血杆菌的免疫增强效果,我们将铝胶、蜂胶和白油3种佐剂分别与副猪嗜血杆菌血清5型菌株联合制备灭活疫苗,然后接种雄性成年家兔,采用ELSIA方法分别检测3种灭活苗在免疫期间副猪嗜血杆菌P5蛋白的抗体效价。结果显示:3次免疫后,白油佐剂免疫组的平均效价为1∶4000,铝胶佐剂免疫组的平均效价为1∶700,蜂胶佐剂免疫组的平均效价为1∶100,无佐剂对照组的平均效价为1∶100。说明这3种佐剂中免疫增强效果最好的为白油,铝胶次之。     

Laboratory assessment of protection given by an experimental Salmonella enteritidis PT4 inactivated, adjuvant vaccine

An experimental inactivated Salmonella enteritidis PT4 vaccine, containing 10(11) cfu/ml and 50 per cent oil adjuvant, was used in laboratory vaccination trials in chickens. A single subcutaneous vaccination at three weeks or two vaccinations at three and six weeks old provided good protection against challenge with 10(9) cfu or 10(8) cfu of virulent organisms administered intramuscularly or intravenously at five and eight weeks old, respectively. The degree of protection was assessed according to the severity of the clinical signs, the mortality, the post mortem lesions and the recovery of the challenge organisms from post mortem material.     

Efficacy of a cold-adapted, intranasal, equine influenza vaccine: challenge trials.

A randomised, controlled, double-blind, influenza virus, aerosol challenge of horses was undertaken to determine the efficacy of a cold-adapted, temperature sensitive, modified-live virus, intranasal, equine influenza vaccine. Ninety 11-month-old influenza-na?ve foals were assigned randomly to 3 groups (20 vaccinates and 10 controls per group) and challenged 5 weeks, 6 and 12 months after a single vaccination. Challenges were performed on Day 0 in a plastic-lined chamber. Between Days 1 and 10, animals were examined daily for evidence of clinical signs of influenza. Nasal swabs for virus isolation were obtained on Day 1 and Days 1 to 8 and blood samples for serology were collected on Days 1, 7 and 14. There was no adverse response to vaccination in any animal. Following challenge at 5 weeks and 6 months, vaccinates had significantly lower clinical scores (P = 0.0001 and 0.005, respectively), experienced smaller increases in rectal temperature (P = 0.0008 and 0.0007, respectively) and shed less virus (P<0.0001 and P = 0.03, respectively) over fewer days (P<0.0001 and P = 0.002, respectively) than did the controls. After the 12 month challenge, rectal temperatures (P = 0.006) as well as the duration (P = 0.03) and concentration of virus shed (P = 0.04) were significantly reduced among vaccinated animals. The results of this study showed that 6 months after a single dose of vaccine the duration and severity of clinical signs were markedly reduced amongst vaccinated animals exposed to a severe live-virus challenge. Appropriate use of this vaccine should lead to a marked reduction in the frequency, severity and duration of outbreaks of equine influenza in North America.     

鸡痘蜂胶佐剂灭活疫苗的研制

鸡痘是危害养鸡业发展的一种传染病，不分日龄大小均可发病，肉鸡和蛋鸡均可感染，发病期1～2周，雏鸡死亡率较高，可达5％～30％不等，近年来发病率和死亡率有上升趋势，并且免疫失败的病例时有发生，为了用疫苗来控制鸡痘的暴发，我们研制了鸡痘蜂胶佐剂灭活疫苗，并用间接ELISA法检测了用弱毒疫苗和灭活疫苗免疫后的抗体水平，现报告如下。     

纳米氢氧化铝吸附禽流感病毒灭活疫苗的研制及其对肉鸡抗体效价的影响

自制纳米氢氧化铝佐剂,通过吸附H5N1灭活抗原,制备了纳米铝佐剂疫苗,按照中华人民共和国农业行业高致病性禽流感免疫技术规范标准,免疫肉鸡。经检测发现纳米铝佐剂疫苗组肉鸡产生有效保护抗体时间较油佐剂疫苗和常规铝佐剂疫苗提前3d和7d,抗体峰值达到时间较油佐剂疫苗和常规铝佐剂疫苗提前14d。结果表明,纳米氢氧化铝作为高致病性禽流感H5N1的免疫佐剂,可以更早的刺激动物产生有效保护抗体,纳米铝佐剂禽流感疫苗具有广泛的应用价值。     

Nucleocapsid of rabies virus improve immune response of an inactivated avian influenza vaccine

The purpose of this study was to determine if nucleocapsid of rabies virus could improve the immune response (humoral and protective) of chickens vaccinated against avian influenza with an inactivated avian influenza experimental vaccine (AIV). On the other hand, AIV with and without NC was compared with an inactivated oil emulsion avian influenza commercial vaccine (CV) virus, currently used in Mexico. Groups of 8 day old chickens were vaccinated intracutaneously with an AIV (group 1); group 2, AIV supplemented with 20 μg of nucleocapsid of rabies virus (NC); Group 3, commercial vaccine (CV) and control groups (4 and 5) with 20 μg of NC and non-infected allantoic fluid, respectively. CV showed a better antibody-mediated response (p < 0.001) after and before challenging; which correlated with the best protection; while NC improved the protection in comparison with group 1. This is the first report on the potential utility of the rabies virus N protein to improve immune response in domestic species.