COMPARISON OF RECOMBINANT VACCINIA AND ALDRITHIOL-2 INACTIVATED SIV VACCINES

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。我们比较了用重组痘苗病毒（rVV）启动和重组SIV蛋白或灭活SIV病毒体增强的“启动-增强”免疫方案的保护效果。用表达SIVmne CL8 Env或Gag/Pol蛋白的两种rVV对三组猪尾猕猴（7/组）进行引物处理，一年后用明胶/MPL佐剂中的重组gp160和Gag/Pol病毒样颗粒增强（1组），仅用佐剂（2组），或2,2'-二硫代二吡啶（aldrithiol-2）灭活SIVmne （AT-2 SIV）增强（3组）。四周后，所有的动物都被静脉注射了一种未克隆的SIVmne。虽然所有动物在攻击后都被感染，但与对照组相比，免疫动物的血浆病毒血症显著降低。病毒血症的减少与高水平的疫苗诱导SIV抗体和ifn - γ ELISPOT应答相关。为了进一步了解这种保护机制，我们分析了非克隆攻击病毒包膜区域的核苷酸序列，并将它们与攻击后2-4周收集的感染动物PBMC中的核苷酸序列进行了比较。来自非克隆攻击病毒的约50%的V1序列与制造疫苗的分子克隆CL8 （CL8型）相同，其余部分包含几个保守的变化（变异型）。感染该非克隆病毒的对照组动物具有不同比例的两种V1序列，其平均值（CL8的38.4%和变异型的61.6%）与攻毒组相似。另一方面，16/17只免疫动物在感染后早期以变异型V1序列为主（96.6 +/- 8.3%）。这些结果支持了我们早期的发现，表明所引发的保护性免疫主要局限于同源病毒，针对包膜蛋白V1区域的免疫反应可能在保护中起作用。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We compared protective efficacy of 'prime-boost' immunization regimens using recombinant vaccinia virus (rVV) for priming and recombinant SIV proteins or inactivated SIV virions for boosting. Three groups of pig-tailed macaques (7/group) were primed with two rVV expressing SIVmne CL8 Env or Gag/Pol proteins and boosted a year later with recombinant gp160 and Gag/Pol virus-like particles in Alum/MPL adjuvant (Group 1), with adjuvant only (Group 2), or with 2,2'-dithiodipyridine (aldrithiol-2)-inactivated SIVmne (AT-2 SIV) (Group 3). Four weeks later, all animals were challenged intravenously with an uncloned SIVmne. While all animals were infected after challenge, immunized animals had significantly reduced plasma viremia compared with controls. Reduction of viremia correlated with high levels of vaccine-induced SIV antibody and IFN-gamma ELISPOT responses at challenge. To gain further insight into the protective mechanism, we analyzed nucleotide sequences in the envelope region of the uncloned challenge virus and compared them with those present in the PBMC of infected animals collected between 2-4 weeks after challenge. Approximately 50% of the V1 sequences from the uncloned challenge virus was identical to the molecular clone CL8 from which the vaccines were made (CL8 type), with the remainder containing several conserved changes (variant type). Na¿ve control animals infected with this uncloned virus had both types of V1 sequences in varying proportions, the mean of which (38.4% of CL8 and 61.6 % of variant type) is similar to that in the challenge stock. On the other hand, 16/17 immunized animals analyzed had predominantly (96.6 +/- 8.3 %) the variant type V1 sequence early after infection. These results support our earlier findings, indicating that the protective immunity elicited is primarily restricted to the homologous virus and that immune responses directed to the V1 region of the envelope protein may play a role in protection.