驴源抗犬细小病毒IgG抗体的制备及其抗病毒活性的分析

Preparation of donkey IgG antibody against canine parvovirus and its antiviral activity

为制备驴源抗犬细小病毒（canine parvovirus,CPV）抗体,首先利用F81猫肾细胞扩增CPV-2a病毒株,经甲醛灭活和氢氧化铝胶乳化,制成CPV灭活疫苗,病毒滴度为10-8.5 TICD50,然后通过肌肉分点注射免疫驴,连续免疫3次（第1次注射3mL,后2次各注射6mL）,每次免疫前采血,分析驴血清的抗体滴度和中和抗体效价;利用盐析法和离子交换层析法分离和纯化驴血清IgG。用IgG处理幼犬（50mg/kg）,用CPV-2a毒株对IgG处理的犬进行攻毒,分析IgG抗CPV的活性。结果显示,免疫3次后驴血清的CPV抗体滴度为1∶8 192,中和抗体效价为28.5。用制备的IgG处理幼犬未发现不良反应,经CPV-2a攻毒实验证实IgG处理犬的发病率和死亡率分别为33%,0%,均明显低于非处理组（分别为100%,83%）,说明制备的驴源IgG具有明显的抗CPV活性。

To prepare donkey antibody against canine parvovirus（CPV）,the CPV-2 astrain was amplified in F81 feline kidney cells.The CPV-2 astrain was inactivated with formaldehyde and emulsified with aluminium hydroxide to prepare inactivated CPV vaccine titered at 10-8.5 TICD50.The inactivated CPV vaccine was used to immunize donkeys by intramuscular injection,and then to booster twice（3 mL of the vaccine was injected at 1 th time,and 6 mL at last two times）.The blood samples were collected before each immunization and the sera were isolated and antibody titers and neutralzing antibodies were measured.The immunoglubulin G（IgG）was isolated with salting-out method from the donkey sera and purified with ion-exchange chromatography.The puppies were treated with IgG（50 mg/kg body weight）and then challenged with CPV-2 a,and the anti-CPV activity of the IgG was analyzed.Results showed that the average antibody titer and neutralizing antibody titer after the third immunization were 1∶8 192 and 28.5,respectively.No obvious adverse reactions were observed in IgG-treated puppies.After challege with CPV-2 a,the morbility and mortality of the IgG-treated puppies were 33% and 0%,respectively,significantly lower than those of the IgG-untreated puppies（100% and 83%,respectively）,indicating that the donkey IgG possesses the antiviral activity against CPV.