An experimental inactivated vaccine against bluetongue.

Bluetongue virus grown in BHK cells was shown to be inactivated in concentrations of betapropiolactone (BPL) higher than 0-15 per cent. When the virus, inactivated with 0-2 per cent BPL and prepared as a double emulsion vaccine, was injected into Cypriot sheep, no untoward reactions were observed and neutralising antibodies developed. The antibody titre reached a high level and persisted for at least a year. After re-vaccination, a secondary response was observed. A bivalent vaccine elicited a response to both virus types incorporated. The possibilities of using a polyvalent inactivated vaccine are discussed.     

An experimental inactivated virus vaccine against bovine ephemeral fever 1. Studies of the virus

Studies were carried out to find methods for obtaining optimum yields of bovine ephemeral fever (BEF) virus and for concentrating the virus in order to develop inactivated virus vaccines. Cells from the SVP cell line, which was derived from the pig kidney PS cell line, were most satisfactory for growing and assaying BEF virus. BHK 21 and Vero cells also gave similar yields of virus but were not as useful for virus assay. A plaque assay in SVP cells, in which there was 0.1 μg of actinomycin D per ml of overlay, produced reproducible clear plaques and was slightly more sensitive than assays in BHK 21 cell roller tubes. High multiplicities of infection (MOI), around 1 PFU/cell, produced low yields of infectious virus, whereas decreasing the MOI approximately 100-fold led to an increase in virus yield of up to four logs. BEF virus could be concentrated using zinc acetate or ammonium sulphate but not polyethylene glycol 6000. Ammonium sulphate proved most suitable and produced an easily handled precipitate with up to 100% recovery of virus infectively, and 100-fold concentration was possible. This concentrated virus could be rapidly desalted by gel filtration through Sephadex G-75. The virus could be further purified by sucrose density gradient ultracentrifugation provided the gradient contained a protein stabilizer of 0.1% bovine serum albumin. Inactivation kinetics with 0.025% β-propiolactone was similar to that reported for other rhabdoviruses.     

An experimental inactivated virus vaccine against bovine ephemeral fever 2. Do neutralizing antibodies protect against infection?

In order to develop a safe vaccine against bovine ephemeral fever (BEF) which could be used in areas normally free of the disease, studies were carried out on inactivated virus vaccines. Initial experiments were carried out in cattle using virus vaccines that had been inactivated with β-propiolactone or formalin and then made-up in aluminium phosphate gel or Freund's incomplete adjuvant. A minimum inactivated virus dose of 10⁶ PFU was necessary to stimulate a serum neutralizing antibody response in cattle. β-propiolactone inactivated BEF virus vaccines in Freund's incomplete adjuvant gave the best serum neutralizing antibody responses, producing high levels of neutralizing antibody with both high and low passage level virus. However, the magnitude of the antibody response bore little relationship to resistance of vaccinated animals to challenge with virulent BEF virus. A number of animals with high neutralizing antibody titres to BEF virus did not resist challenge. Using 500-fold less live virus at equivalent passage level to the low passage inactivated vaccine, similar or slightly lower antibody levels were attained, but most of the animals resisted challenge. It is suggested that the nature of the immune response and resistance to BEF infection may be complex and that reliance on serum neutralizing antibody as an indicator of resistance may give misleading results.     

Field trials of an inactivated virus vaccine against porcine parvovirus.

Serological response and reproductive performance were estimated in field trials of an inactivated virus vaccine against porcine parvovirus. Experiments were carried out in 10 selected pig breeding herds. A total of 277 seronegative gilts were used. Two hundred and twenty animals were vaccinated twice before mating, fourteen days apart and revaccinated after farrowing. Blood samples were obtained from both vaccinated and non-vaccinated (57 animal) control gilts, one week after the 2nd dose of vaccination, at farrowing time and one week after revaccination. Although there were considerable variations among the herds, the number of returns to oestrus in all herds was higher in vaccinated gilts (11.81%) than in the controls (10.52%). This difference, however, was not statistically significant. The reproductive performance results revealed the absence of an increase in the total born, as pooled values, in vaccinated gilts compared to controls. However, when these results are interpreted in relation to serological data, many control gilts were already seropositive before mating, or remained seronegative at farrowing. According to our results, the duration of immunity with this vaccine is apparently short, as there is a clear decrease in the titres between the 1st and the 2nd sampling times (2.35 +/- 0.14 and 1.97 +/- 0.08, respectively).     

乳牛衣原体病灭活疫苗的研制

将免疫原性稳定的鹦鹉热衣原体SX5菌株灭活，加入油佐剂制备乳牛衣原体病灭活疫苗，并对疫苗的安全性进行了检测。用该疫苗对成年牛和犊牛进行了最小免疫量试验、效力试验和免疫持续期试验；结果表明，最小免疫量分别为3mL和5mL，平均免疫保护率达94．4％。免疫持续期达10个月。疫苗保存期试验表明，在4℃条件下可保存12个月。本动物安全试验和田间小试免疫证明，该疫苗安全性好，乳牛注射疫苗后饮食、产乳量及注苗部位没有明显的异常变化。     

牛冠状病毒灭活疫苗的免疫效力试验

为了评价制备的牛冠状病毒灭活疫苗的免疫效力,试验选用分离鉴定出来的牛冠状病毒(BCV-YC分离株)为制苗种毒,接种HRT-18细胞进行增殖,收集上清液进行超速离心浓缩,最后加入甲醛灭活制成油乳剂灭活疫苗,分别接种小鼠和妊娠母牛。结果表明,疫苗不仅使小鼠具有一定的保护力,而且使妊娠母牛也能产生较高的抗体水平,犊牛攻毒试验证明,产生的母源抗体能使初生犊牛抵抗牛冠状病毒的攻击。说明制备的牛冠状病毒灭活疫苗对抵抗牛冠状病毒感染具有良好的保护性。     

Efficacy of an inactivated vaccine against hydropericardium syndrome in broilers

Field trials were used to assess the efficacy of an inactivated vaccine against hydropericardium syndrome in broiler chickens. A single vaccination at 10 to 12 days old was effective for the control of the syndrome; mortality in the vaccinated birds was 0.52 per cent compared with 5.34 per cent in unvaccinated birds kept at the same premises. Vaccination was also effective when carried out in the face of an outbreak; mortality in the vaccinated infected birds was 2.33 per cent compared with 10.27 per cent in unvaccinated infected birds. The data indicate that a formalinised vaccine prepared from the liver of experimentally infected birds could be used for the control of hydropericardium syndrome.     

鸭副黏病毒油乳剂灭活疫苗的制备

将分离的鸭副黏病毒,经0.1%的甲醛灭活后与白油、吐温-80、司盘-80,按一定比例混合后在胶体磨中快速乳化成油包水型,制备了鸭副黏病毒油乳佐剂灭活疫苗。并对制备的疫苗进行了物理性状、无菌检验、安全性、稳定性检验、抗体消长规律、交叉免疫保护及免疫效力检验。结果表明,该疫苗安全可靠,注射后鸭的精神状况良好,饮食、粪便无异常变化,注射部位未见明显变化,疫苗吸收良好。免疫后14d即可产生抗体（平均为41og2）,60d可达到91og2。免疫后25d攻毒保护率可达90%以上。     

鸡轮状病毒灭活油乳疫苗的制备与应用研究

利用从发生流行性腹泻的发病鸡中分离的轮状病毒,研制了鸡轮状病毒灭活油乳疫苗,并对该疫苗的安全性及免疫效果进行了测定.结果表明该疫苗安全可靠,注射后对增重、产蛋均无影响.免疫后14 d攻毒保护率可达98%以上,免疫期可维持6个月,4℃保存12个月,10℃～25℃保存3个月,免疫效果不变.对鸡轮状病毒油乳灭活疫苗在山东不同地区进行田间试验和扩大区域试验,结果表明该疫苗性能良好、安全,对蛋鸡、肉鸡、雏鸡的生产性能无明显影响,疫苗接种后保护率可达92%以上,可有效地控制该病的发生.     

肠炎沙门氏菌灭活苗制作和应用

肠炎沙门氏菌属于无宿主特异性而有侵害性的病原菌之一，宿主包括人和各种动物。该菌不仅能引起家禽发病死亡造成严重的经济损失，而且被污染的家禽产品作为肠炎沙门氏菌的携带者，还严重危害人类健康。据报道，日、美等发达国家发生的食物中毒事件中40％～80％是由禽沙门氏菌引起的，其中主要病原为肠炎沙门氏菌(S G Mellroy，et al．1989)。由肠炎沙门氏菌引起人的急性胃肠炎(食物中毒)，在世界各国有增加的趋势，     

Immunization of cattle against Aujeszky's disease with inactivated adjuvant vaccine

The experiments with sheep and young cattle were carried out to test the immunizing efficacy of inactivated adjuvant vaccine against Aujeszky's disease. The vaccine application at doses of 1 ml and 2 ml to lambs at the age of eight to ten months caused the neutralizing antibody production with a significant rise of titres after revaccination. A survival of infection induced with a dose of 10(5.5) TKID50 of virulent virus was recorded in 62.5% of once vaccinated animals and in 87.5% of twice vaccinated animals. When applying different doses of vaccines (from 1 to 10 ml) to young cattle, the antibody reaction level was directly dependent on the inoculum quantity. The double inoculation of animals with vaccines of 2 ml and 5 ml caused the neutralizing antibody production at titres of 1:35, or 1:46. The animals, immunized with the live or inactivated IBR-vaccine possessing high antibody titres against IBR-virus, reacted upon the vaccination with inactivated Aujeszky's vaccine anamnestically, by early production of antibodies in high titres. Metaphylactic vaccination (2 ml of vaccine) of cattle in herds with an acute course days, however earlier during five days from the revaccination when it was carried out in seven days following the first vaccination.     

鸭瘟灭活疫苗效力试验和安全试验

将已建立的鸭瘟病毒(DPV)AV1221株基础种毒经鸭胚繁殖、收集胚液病毒、0.2%甲醛溶液灭活后,与矿物油佐剂乳化制备了3批鸭瘟灭活疫苗.成鸭的免疫攻毒测定,疫苗最小免疫剂量为0.12 mL,确定使用剂量为每羽份0.5 mL.单剂量、单剂量重复和超剂量安全试验结果显示,疫苗不引起产蛋鸭的全身不良反应和明显的局部反应.疫苗的免疫攻毒试验结果表明,疫苗在不同品种的成鸭中,使用不同的免疫途径,均能诱导产生80%以上保护;在雏鸭中,经二次免疫也能够诱导产生80%以上保护.疫苗一次免疫鸭后,不同时间诱导产生的中和抗体滴度(GMT)分别是,7 d为1:3.2、10 d为1:4.6、14 d为1:8,21 d、30 d和60 d均为1:7;免后10 d可以产生80%攻毒保护,14 d和21 d可产生完全保护.疫苗的免疫持续期试验结果表明,成鸭经1次免疫后150 d,雏鸭经二次免疫后60 d均可维持80%以上保护.     

Immunisation against ringworm in cattle

Immunisation against dermatomycoses in cattle was introduced in Gausdal, Norway, in 1979. A programme was implemented in which a six-year period of mandatory vaccination of all cattle was followed by vaccination on a voluntary basis. The prevalence of infected herds fell from 70 per cent in 1979 to 0 per cent in 1987. During the last five years, no newly infected herds have been registered in Gausdal. Proper disinfection of premises, the isolation of infected animals and other hygienic measures contributed to the successful result.     

Protection against feline leukemia virus infection by use of an inactivated virus vaccine.

The protective immunity induced by 3 experimental FeLV vaccines were evaluated: Prototype inactivated FeLV vaccine developed from a molecularly cloned FeLV isolate (FeLV-FAIDS-61E-A); a mixture of immunodominant synthetic peptides corresponding to regions of the FeLV-Gardner-Arnstein-B (FeLV-GA-B) envelope proteins; and an adjuvant-disrupted but non-activated virus prepared from a non-cloned FeLV field isolate comprised of subgroup A and B viruses (FeLV-05821-AB). Included as controls were parallel groups of cats inoculated with adjuvants alone or with an established commercial FeLV vaccine. After each inoculation and after virulent virus challenge exposure, sera from all cats were assayed for ELISA-reactive antibody against purified FeLV, FeLV neutralizing (VN) antibody, and FeLV antigenemia/viremia--viral p27 antigen in serum and within circulating leukocytes. Immunity was challenged by oral/nasal exposure of vaccinated and control cats with FeLV-FAIDS-61E-A or FeLV-05821-AB, an infective, noncloned, tissue-origin, FeLV field isolate containing subgroup-A and -B viruses. Vaccine-induced immunity was assessed by comparing the postchallenge-exposure incidence of persistent viremia and the pre- and postchallenge exposure titers of VN and ELISA antibody in cats of the control and vaccine groups. The percentage of cats, that resisted development of persistent viremia after FeLV challenge exposure and the preventable fraction (PF) for the vaccine groups (which adjusts for the severity of the challenge and the degree of innate resistance in the controls) were as follows: adjuvant controls, 26%; FeLV-FAIDS-61E-A inactivated virus vaccine, 95% (PF = 93.2%); FeLV-GA-B peptide vaccine, 5% (-28.4%); FeLV-05821-AB noninactivated vaccine, 67% (55.4%); and commercial FeLV vaccine, 35% (12.2%). The prechallenge exposure mean VN antibody titer for each group was: less than 1:8 in the adjuvant controls; 1:43 in the FeLV-FAIDS-61E-A-vaccinated cats; less than 1:8 in the peptide-vaccinated cats; 1:38 in the noninactivated virus-vaccinated cats group; and 1:12 in the cats vaccinated with the commercial vaccine. Thus, induction of VN antibody in the vaccinated cats, although modest, appeared to be correlated with induction of protective immunity as defined by resistance to FeLV challenge exposure. Results of these studies indicate that inoculation of cats with an experimental inactivated virus vaccine prepared from a molecularly cloned FeLV isolate was most effective in stimulating protective immunity against heterologous and homologous FeLV challenge exposure.     

溶血性曼氏杆菌灭活菌苗制备中免疫佐剂的应用研究

近几年来，随着我国集约化养殖业的迅速发展，畜牧业已成为农村经济的支柱产业，在国民经济中发挥着越来越重要的作用。与此同时，为保障畜牧业的健康发展，对畜禽传染病的防治也提出了更高要求，有效地控制传染病的发生，减少传染病对畜牧业生产的危害，为人民生活提供更多、更安全的畜产品是传染病防治的重要任务。     

Anaplasma marginale inactivated vaccine: dose titration against a homologous challenge

The present study was performed to dose-titrate an Anaplasma marginale experimental immunogen derived from partially purified initial bodies from three geographically different Mexican strains. Three five-bovine groups were inoculated twice on days zero and 21 with A. marginale initial bodies equivalent to 1.5×10¹⁰ (group I), 3×10¹⁰ (group II) or 6×10¹⁰ (group III) infected erythrocytes mixed with STDCM® adjuvant. A similar group served as non-vaccinated controls. All four groups were challenged with 1×10⁸ infected erythrocytes from a donor cow with an increasing rickettsemia of strain MEX-15 on day 87 post-vaccination. The prepatent period was very similar for all four groups. All five non-vaccinated controls presented typical acute anaplasmosis syndrome reaching a mean of 30.9% rickettsemia and a loss of 73.4% in the packed cell volume (PCV). Two of five controls died of acute anaplasmosis. Within the vaccinated groups only one animal (group II) suffered acute disease and died. Although all the other vaccinated animals were free of clinical signs, they developed very low rickettsemias (3.2, 3.8 and 4.3%) and PCV losses of 49.9, 47.8, and 49.3% for groups I, II and III. The starting mean weight was very similar for all four groups. All animals lost weight following challenge but losses for groups I and II were lower and significantly different from group IV losses (P0.1). Although there were no significant differences among vaccinated groups, group III was more severely affected. Taken altogether, these results show a 93.3% protection against both illness and death for all groups; and 100% protection for groups I and III, and 80% for group II.