PROTECTIVE EFFICACY OF GLYCAN-MODIFIED ENV VACCINE

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 我们先前表明，用N7 Env免疫猪尾猕猴，其在氨基酸残基197处去除了N-连接聚糖，导致增强的中和抗体（NA B）应答，不仅针对同源病毒89.6，而且针对HIV-1 SF 162和一组标准亚型B主要分离株。在本研究中，我们旨在扩展这些研究，以评估N7 Env疫苗对异源CCR 5病毒攻击的保护效力。我们用“初免-加强”方案免疫三组猪尾猕猴（N=6/组），所述方案由用重组牛痘病毒初免和用重组蛋白加强组成。这些组中的两组用野生型或突变型N7 Env疫苗免疫。另一组动物接受N7 Env和SIV Gag-Pol疫苗。对照动物仅接受亲本牛痘病毒和佐剂。所有动物产生慢病毒特异性抗体应答，包括针对异源病毒SF 162的NAb，尽管比我们在上述第一项研究中观察到的少5- 10倍。这促使我们进行额外的加强免疫。然而，未观察到NAb滴度增加，这与应答程度主要由初次免疫的有效性决定的观点一致。直肠内接种SHIV 162 P4攻毒后，所有对照和免疫动物均被感染，与攻毒当天Nab滴度的低滴度一致。然而，用N7 Env免疫的动物显示出峰值病毒载量的显著降低，并且接受N7 Env和SIV Gag-Pol疫苗的动物显示出设定点病毒载量的降低。这些结果表明，针对异源病毒的保护性免疫可通过初免加强免疫方案产生。该实验于2010年7月结束，其余动物转移至Colony Health进行随访研究。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. We previously showed that immunization of pig-tailed macaques with the N7 Env, which had a N-linked glycan at amino acid residue 197 removed, resulted in enhanced neutralizing antibody (NAb) response not only against the homologous virus, 89.6, but also HIV-1 SF162 and a standard panel of subtype B primary isolates. In this study, we aimed to extend these studies to evaluate the protective efficacy of N7 Env vaccines against a heterologous CCR5 virus challenge. We immunized three groups of pig-tailed macaques (N=6/group) with a "prime-boost" regimen, consisting of priming with recombinant vaccinia virus and boosting with recombinant proteins. Two of these groups were immunized with either wild-type or mutant N7 Env vaccines. An additional group of animals received both N7 Env and SIV Gag-Pol vaccines. Control animals received parental vaccinia virus and adjuvant only. All animals generated lentivirus-specific antibody responses, including NAb against the heterologous virus SF162, albeit at 5- to10-fold less than what we observed in the first study described above. This prompted us to administer an additional booster immunization. However, no increase in NAb titer was observed, consistent with the notion that the magnitude of response was determined largely by the effectiveness of the primary immunization. After challenge with an intrarectal inoculation of SHIV162P4, all control and immunized animals were infected, consistent with the low titer of Nab titer at the day of challenge. However, animals immunized with the N7 Env showed significant reduction of peak viral load and those received both N7 Env and SIV Gag-Pol vaccines showed reduction of setpoint viral loads. These results indicate that protective immunity against a heterologous virus can be generated by the prime boost immunization regimen. This experiment was concluded in July, 2010 and the remaining animals transferred to Colony Health for follow up studies.