【作者】 王家福；

【导师】 刘金华；

【作者基本信息】 中国农业大学 ， 预防兽医学， 2005， 硕士

【摘要】 口蹄疫（Foot and mouth disease, FMD）是由口蹄疫病毒（FMDV）引起的主要危害牛、猪、羊等偶蹄动物的烈性传染病,发病率高,传染性强,并能形成国际大流行,国际兽疫局（OIE）将其排在A类家畜传染病的首位。世界各国政府都高度重视本病的防治工作。疫苗免疫是防制本病的重要手段之一,近一个世纪以来,许多国家为了预防和控制口蹄疫的发生和流行,对疫苗的研究一直是该领域的研究热点。 我国目前防制家畜口蹄疫病主要以使用抗原（病毒培养液）不经过浓缩的普通灭活疫苗为主,一般每头剂量3ml仅含3个PD₅₀。因普通疫苗的抗原未经浓缩处理抗原含量偏低,同时存在一定量的细胞碎片等非抗原蛋白成份,所以保护力低、免疫期相对较短,并有一定的副反应。 本研究通过对口蹄疫病毒抗原的高倍浓缩等一系列手段制备出符合国际标准的新型疫苗并中试放大,摸索出一套新的生产工艺。通过对疫苗毒株的各种生物学特性尤其是病毒毒力和免疫原性、病毒液的前处理和高倍超滤浓缩工艺、浓缩后病毒含量检测方法和标准的建立(运用ELISA、TCID₅₀等手段建立新的检测方法并与乳鼠LD₅₀试验平行比较)、应用国际通行标准（OIE）对疫苗进行PD₅₀测定并与普通疫苗的效力相比较等研究试验,最终研制成功的三批疫苗在实验室和田间试验中均达到了预先规定的各项标准:1.提高了安全性:动物注射疫苗后安全而无副作用。2.降低了使用剂量:2ml/头剂（普通疫苗使用量为3ml）。3.提高了免疫效力:每头剂达到6个PD₅₀以上(普通疫苗每头剂含3个PD₅₀)。4.延长了免疫持续期:达到6～7个月（普通疫苗为4个月左右）。 目前,该疫苗已通过农业部的新兽药证书的评审,预期在我国口蹄疫疫病的防治中将发挥重要作用。更多还原

【Abstract】 Foot and Mouth Disease （FMD）, a major threat to cloven-hoofed animals such as bovine, swine and sheep, is a highly contagious disease caused by Foot and Mouth Disease Virus （FMDV）. Since it has a high incidence and can easily cause an epidemic outbreak and enormous loss of economy, Office International des Epizooties （OIE） ranks it in the first in all contagious diseases for domestic animals. The governments of countries all over the world have focused much attention on the prevention and control of this disease.Since vaccination was one of major means to prevent domestic animals from this disease, many countries paid much attention to the development of FMDV vaccines for almost a century in order to prevent and control the outbreak and prevalence of FMD.Thus far, the means mainly adopted in China to prevent domestic animals from the infection of FMDV is the use of the crude, non-concentrated preparation from the viral culture prior to chemical inactivation. In general, the guideline of a FMDV vaccine requires that 3 milliliters per dose per animal contain 3 PD₅₀ or that the protection rate after the viral challenge should reach at 4 protected out of 5 tested animals or greater. Since the concentration of viral antigens in the non-concentrated crude viral preparation is relatively low and it contains a trace amount of nonantigenic proteins from the host cell debris, this makes the vaccines usually in a weak protection, a relatively short duration for immune response and side-effects.The purpose of this study is to, through a series of means including a concentration process of the FMDV antigens, produce a higher standard vaccine to meet the international criteria and subsequently scale up the production, thus exploring a set of new technologies for the production. The aim of such new vaccine mainly focuses on improving the efficacy of the present vaccine and achieving the criteria as follows:1. The increasing of the safety: The inoculation of the vaccine is safer to animals with minimal side-effects.2. The reduction of the volume per dose: Each dose of the vaccine is 2 milliliters per animal instead of 3 milliliters from the pre-improved vaccine.3. The improvement of the efficacy: Each dose of the vaccine contains more than 6 PD₅₀, rather than 3 PD₅₀ from the pre-improved vaccines.4. The longer duration of the immune response: The vaccine can improve the duration from 4 to 4.5 months to 6 to 7 months.Through examining the biological characteristics of the vaccine strain especially for its the virulence and immunogenecity, evaluating the pre-process for the viral culture and the concentration technology, establishing the testing standard protocol for the viral antigen content after concentration (the results from the established new testing protocol obtained from ELISA and TCID₅₀ were consistent with the results obtained from the suckling mouse LD₅₀ protocol), using international standard to determine the PD₅₀ and comparing the efficacy with the pre-improved vaccines, three batches of tested vaccines all met every preset criterion in both laboratory and field test with a 100% success. To date, this vaccine has been passed the assessment and evaluation by the Ministry of Agriculture of the People’s Republic of China and will be certificated for the license soon.更多还原