Huismans H, Erasmus B J
Onderstepoort J Vet Res. 1981 Jun;48(2):51-8.
The bluetongue virus (BTV) core particle contains 2 major polypeptides, P3 and P7, and is surrounded by an outer capsid layer that is composed of the 2 major polypeptides, P2 and P5. Analysis of the immune precipitates from soluble 14C-labelled BTV polypeptides and hyper-immune rabbit and guinea-pig sera indicated that polypeptide P2 precipitates only with homologous BTV sera. This would indicate that P2 is the main determinant of serotype specificity. It was also found that in sheep infected with BTV the P2-precipitating antibodies in the serum correlate with the neutralizing antibody titres, whereas the appearance and subsequent decline of P7-precipitating antibodies correspond well with those of the complement fixing antibodies. This suggests that BTV group specificity, as measured by a complement fixation tests, is determined by the core protein P7. This result was supported by the observation that mouse ascitic fluid, which contains a high titre of BTV-specific complement fixing antibodies and a very low titre of neutralizing antibodies, contains almost exclusively antibodies that precipitate P7.
蓝舌病毒（BTV）核心颗粒包含两种主要多肽，P3和P7，并被由两种主要多肽P2和P5组成的外衣壳层所包围。对可溶性14C标记的BTV多肽以及超免疫兔和豚鼠血清的免疫沉淀物分析表明，多肽P2仅与同源BTV血清发生沉淀反应。这表明P2是血清型特异性的主要决定因素。还发现，在感染BTV的绵羊中，血清中沉淀P2的抗体与中和抗体滴度相关，而沉淀P7的抗体的出现及随后的下降与补体结合抗体的情况非常吻合。这表明，通过补体结合试验测定的BTV群特异性由核心蛋白P7决定。这一结果得到以下观察结果的支持：含有高滴度BTV特异性补体结合抗体和极低滴度中和抗体的小鼠腹水几乎只含有沉淀P7的抗体。
