犬瘟热疫苗弱毒的复壮与免疫试验

Conversion to Higher Immnogenicity of an Over Attenated Canine Distemper Virus Vaccine Strain

将一株犬瘟热疫苗株病毒通过Ｖｅｒｏ细胞２０代（ＣＤＶ／Ｒ－２０）后又通过敏感犬的腹腔巨噬细胞，获得一株免疫原性更高的弱毒株（ＣＤＶ／Ｒ－２０／８）。接种同样剂量１０４ＴＣＩＤ５０的ＣＤＶ／Ｒ－２０／８和ＣＤＶ／Ｒ－２０的犬，产生出血清中和（ＳＮ）抗体价的几何平均数分别为１：５４和１：２６。前者为后者的２倍多。接种１０５ＴＣＩＤ５０的ＣＤＶ／Ｒ－２０／８能完全保护犬（１０／１０）抵抗ＣＤＶ强毒的攻击，接种１０４ＴＣＩＤ５０的保护９／１０犬，而对照犬５只全部发病，其中４只死亡。犬体内ＳＮ价可持续一年之久。冻干培养物在４和－３０℃中可分别保存９个月和１２个月而效力不减。

An attenuated with higher immnogenicity canine distemper virus(CDV) was gained by passing an over attenuated CDV vaccine strain virus through the vevo cells for 20 passagges (CDV/R 20) and then the macrophages of sensitive dog'sabdominal cavity for 8 passages(CDV/R 20/8) .Dogs inoculated with the CDV/R 20/8 and CDV/R 20 in a similar doses of 10 4 TCID 50 produced serum neutralization antibody titers in geometric arerage of 1:54 and 1:26 respectively. The former was twice higher than the latre. Inoculation with 10 5TCID 50 of CDV/R 20/8 protected all the 10 dogs against challenging with a virulent CDV. A dose of 10 4TCID 50 protected 9/10 dogs,whereas all the 5 unvaccinated control dogs diseased and 4 died. The SN antibody titer lasted one year in dogs, and the CDV/R 20/8 virus culture maintained its potency for 9 and 12 months when stored the freeze drying cultures in 4℃ and -30 ℃ respectively.