Section for Virology, DTU National Veterinary Institute, Technical University of Denmark, Lindholm, DK-4771 Kalvehave, Denmark; Section for Molecular Disease Biology, Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Dyrlaegevej 88, 1, DK-1870 Frederiksberg C, Denmark.
Section for Virology, DTU National Veterinary Institute, Technical University of Denmark, Lindholm, DK-4771 Kalvehave, Denmark.
Vet Microbiol. 2014 Jun 4;170(3-4):224-31. doi: 10.1016/j.vetmic.2014.02.018. Epub 2014 Feb 17.
Live modified vaccines to protect against classical swine fever virus (CSFV), based on chimeric pestiviruses, have been developed to enable serological Differentiation of Infected from Vaccinated Animals (DIVA). In this context, the chimeric virus CP7_E2gif vaccine candidate is unique as it does not include any CSFV components. In the present study, the DIVA vaccine properties of CP7_E2gif were evaluated in comparison to the conventional live attenuated Riemser C-strain vaccine. Sera and tonsil samples obtained from pigs immunised with these two vaccines were analysed. No viral RNA was found in serum after vaccination with CP7_E2gif, whereas some serum samples from C-strain vaccinated animals were positive. In both vaccinated groups, individual viral RNA-positive tonsil samples were detected in animals euthanised between 7 and 21 days post vaccination. Furthermore, serum samples from these animals, together with archival samples from pigs vaccinated with CP7_E2gif and subsequently CSFV challenged, were analysed for specific antibodies using ELISAs and for homologous neutralising antibodies. In animals vaccinated with CP7_E2gif, neutralising antibodies were detected from day 10. However, the sera remained negative for anti-CSFV E2-specific antibodies whereas pigs vaccinated with C-strain seroconverted against CSFV by 14 days after vaccination, as determined by a CSFV-E2 specific blocking ELISA. One week after subsequent CSFV challenge, a strong anti-CSFV E2 reaction was detected in CP7_E2gif vaccinated pigs and anti-E(rns) antibodies were detected from 10 days after infection. In conclusion, CP7_E2gif has the potential to be used as a DIVA vaccine in combination with detection of anti-CSFV E2-specific antibodies.
为了能够对感染动物和免疫动物进行血清学区分（DIVA），基于嵌合瘟病毒，已经开发出了用于预防经典猪瘟病毒（CSFV）的活体改造疫苗。在这种情况下，CP7_E2gif 嵌合病毒疫苗是独一无二的，因为它不包含任何 CSFV 成分。在本研究中，将 CP7_E2gif 与传统的活减毒 Riemser C 株疫苗进行了比较，以评估其 DIVA 疫苗特性。对用这两种疫苗免疫的猪的血清和扁桃体样本进行了分析。用 CP7_E2gif 接种后，血清中未发现病毒 RNA，而接种 C 株疫苗的一些血清样本呈阳性。在这两个免疫组中，在接种后 7 至 21 天处死的动物中，均检测到个别扁桃体样本呈病毒 RNA 阳性。此外，对这些动物的血清样本以及用 CP7_E2gif 免疫后接种 CSFV 并保存的存档样本，使用 ELISA 进行了特异性抗体分析和同源中和抗体分析。用 CP7_E2gif 免疫的动物，从第 10 天开始检测到中和抗体。然而，用 CP7_E2gif 免疫的动物的血清仍对 CSFV E2 特异性抗体呈阴性，而接种 C 株疫苗的动物在接种后 14 天就发生了 CSFV 血清转化，这通过 CSFV-E2 特异性阻断 ELISA 来确定。在随后接种 CSFV 一周后，在 CP7_E2gif 免疫的猪中检测到强烈的抗 CSFV E2 反应，并且从感染后第 10 天开始检测到抗 E(rns)抗体。总之，CP7_E2gif 有可能与检测 CSFV E2 特异性抗体结合，用作 DIVA 疫苗。
