Craigo Jodi K, Durkin Shannon, Sturgeon Timothy J, Tagmyer Tara, Cook Sheila J, Issel Charles J, Montelaro Ronald C
Department of Molecular Genetics and Biochemistry, W1144 Biomedical Science Tower, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, United States.
Vaccine. 2007 Jan 15;25(5):834-45. doi: 10.1016/j.vaccine.2006.09.040. Epub 2006 Sep 22.
We previously reported that an experimental live-attenuated equine infectious anemia virus (EIAV) vaccine, containing a mutated S2 accessory gene, provided protection from disease and detectable infection after virulent virus (EIAV(PV)) challenge [Li F, Craigo JK, Howe L, Steckbeck JD, Cook S, Issel C, et al. A live-attenuated equine infectious anemia virus proviral vaccine with a modified S2 gene provides protection from detectable infection by intravenous virulent virus challenge of experimentally inoculated horses. J Virol 2003;77(13):7244-53; Craigo JK, Li F, Steckbeck JD, Durkin S, Howe L, Cook SJ, et al. Discerning an effective balance between equine infectious anemia virus attenuation and vaccine efficacy. J Virol 2005;79(5):2666-77]. To determine if attenuated EIAV vaccines actually prevent persistent infection by challenge virus, we employed a 14-day dexamethasone treatment of vaccinated horses post-challenge to suppress host immunity and amplify replication levels of any infecting EIAV. At 2 months post-challenge the horses were all protected from virulent-virus challenge, evidenced by a lack of EIA signs and detectable challenge plasma viral RNA. Upon immune suppression, 6/12 horses displayed clinical EIA. Post-immune suppression characterizations demonstrated that the attenuated vaccine evidently prevented detectable challenge virus infection in 50% of horses. These data highlight the utility of post-challenge immune suppression for evaluating persistent viral vaccine protective efficacy.
我们之前报道过，一种含有突变S2辅助基因的实验性减毒马传染性贫血病毒（EIAV）疫苗，在受到强毒病毒（EIAV(PV)）攻击后可提供疾病防护和可检测到的感染防护[Li F, Craigo JK, Howe L, Steckbeck JD, Cook S, Issel C等。一种具有修饰S2基因的减毒马传染性贫血病毒前病毒疫苗可通过静脉注射强毒病毒攻击实验接种的马匹来提供可检测到的感染防护。《病毒学杂志》2003年；77(13):7244 - 53；Craigo JK, Li F, Steckbeck JD, Durkin S, Howe L, Cook SJ等。在马传染性贫血病毒减毒和疫苗效力之间找到有效的平衡。《病毒学杂志》2005年；79(5):2666 - 77]。为了确定减毒EIAV疫苗是否真的能预防挑战病毒的持续感染，我们在接种疫苗的马匹受到攻击后采用了为期14天的地塞米松治疗，以抑制宿主免疫力并放大任何感染的EIAV的复制水平。在受到攻击后2个月，所有马匹都受到了强毒病毒攻击的保护，表现为缺乏EIA症状和可检测到的攻击血浆病毒RNA。免疫抑制后，12匹马中有6匹出现了临床EIA。免疫抑制后的特征表明，减毒疫苗显然在50%的马匹中预防了可检测到的挑战病毒感染。这些数据突出了攻击后免疫抑制在评估持续性病毒疫苗保护效力方面的效用。
