Molitor T W, Joo H S, Collett M S
J Virol. 1985 Aug;55(2):257-63. doi: 10.1128/JVI.55.2.257-263.1985.
We compared the molecular, antigenic, and pathogenic properties of KBSH parvovirus to those of porcine parvovirus (PPV) isolate NADL-8. KBSH, propagated in swine testes cells in culture, possessed two major capsid polypeptides of 83 and 64 kilodaltons that were similar in size to those of PPV. KBSH-infected cells also contained an 86-kilodalton nonstructural polypeptide that was identical in size to the PPV nonstructural polypeptide (NS-1). The KBSH polypeptides were structurally similar but not identical to the corresponding PPV polypeptides, as revealed by partial proteolysis mapping. Viral replicative-form DNA from KBSH-infected cells was similar in size to PPV replicative-form DNA and exhibited similar but not identical restriction endonuclease cleavage patterns to that of PPV replicative-form DNA. Antigenically, the two viruses were also very closely related. By using heterologous and homologous antisera, the two viruses were indistinguishable in hemagglutination inhibition and immunoprecipitation assays. However, pathogenically these viruses were dramatically different. NADL-8 caused fetal death when injected into swine fetuses in utero and viremia and high persisting antibody titers when administered orally to weaning-age swine. KBSH-inoculated fetuses were normal in appearance, and pigs orally exposed to KBSH failed to establish viremia and demonstrated only transient antibody titers. Thus, KBSH appears to be a PPV that is very closely related to a highly pathogenic PPV isolate, yet is itself nonpathogenic in swine. This reduced pathogenic potential of KBSH may be attributable to its poor ability to replicate in swine.
我们比较了KBSH细小病毒与猪细小病毒（PPV）分离株NADL-8的分子、抗原和致病特性。在培养的猪睾丸细胞中增殖的KBSH具有两条主要的衣壳多肽，分子量分别为83和64千道尔顿，其大小与PPV的相似。感染KBSH的细胞还含有一种86千道尔顿的非结构多肽，其大小与PPV非结构多肽（NS-1）相同。部分蛋白酶解图谱显示，KBSH多肽与相应的PPV多肽在结构上相似但并不相同。来自感染KBSH细胞的病毒复制型DNA大小与PPV复制型DNA相似，并且与PPV复制型DNA表现出相似但不完全相同的限制性内切酶切割模式。在抗原性方面，这两种病毒也非常相近。通过使用异源和同源抗血清，在血凝抑制和免疫沉淀试验中无法区分这两种病毒。然而，在致病性方面，这些病毒却有显著差异。将NADL-8经子宫内注射到猪胎儿体内会导致胎儿死亡，经口给断奶仔猪接种会导致病毒血症和持续的高抗体滴度。接种KBSH的胎儿外观正常，经口接触KBSH的猪未出现病毒血症，仅表现出短暂的抗体滴度。因此，KBSH似乎是一种与高致病性PPV分离株密切相关的PPV，但它本身在猪中无致病性。KBSH这种降低的致病潜力可能归因于其在猪体内复制能力较差。
