Safety and potency studies of HIV DNA vaccines

鉴于体液免疫、细胞免疫和免疫应答都可能对艾滋病起重要作用，我们构建了两个HIV-1多基因表达载体DNA，分别含有人巨细胞病毒启动子和小鼠内源性AKV启动子调控下的pNL4-3DNA的gag和env基因。通过直接注射DNA对恒河猴和猪尾猕猴进行体液免疫和T细胞增殖性免疫反应的分析。在恒河猴和猪尾猕猴中，这两种DNA产生的T细胞增殖反应水平相似，而恒河猴和猪尾猕猴的体液反应与疫苗DNA的启动子强度直接相关。与使用AKV-DNA相比，使用更少的CMV-DNA产生长期可增强的GAG和Env抗体。破伤风类毒素注射用于证明动物对已知抗原的反应类似的能力。为了评估对HIV-1的保护，用DNA疫苗接种的猪尾猕猴和恒河猴一次注射寡聚体gp160(以增强环境反应)。免疫后4周的Env抗体效价评估表明，HIV-1DNA疫苗组动物的gp120和gp41抗体效价均高于对照组。未检测到中和抗体。用SIV-IIIb攻击恒河猴。在蛋白免疫后4周，HIV-1DNA疫苗+蛋白免疫导致血浆病毒RNA下降，表明动物获得了部分保护。猪尾猕猴被感染了HIV-1病毒。HIV-1DNA疫苗接种动物的血浆病毒载量分析表明，在接种CMV-HIV DNA的动物中，BDNA PCR检测不到可检测到的病毒。研究人员正在调查PBMC中的病毒序列，以确定在DNA疫苗接种的动物中是否实现了完全保护。

Summary: Since both humoral and cellular and immune responses may be important against AIDS, two HIV-1 multigenic plasmid DNAs were constructed containing the gag and env genes from pNL4-3 DNA under the regulation of the human CMV and murine endogenous AKV promoters. Development of humoral and T cell proliferative immune responses were analyzed by direct DNA injection of rhesus and pig-tailed macaques. Similar levels of T-cell proliferative responses were generated with both DNAs in rhesus macaques whereas the humoral responses in rhesus and pig-tailed macaques correlated directly with the promoter strength of the vaccine DNA. Long-term, boostable antibodies to Gag and Env were generated using less amount and fewer injections of CMV-DNA than with AKV-DNA. Tetanus toxoid injection was used to demonstrate ability of the animals to respond similarly to a known antigen. To evaluate protection against HIV-1, DNA vaccinated pig-tailed and rhesus macaques were boosted with a single injection of oligomeric gp160 (to enhance the env response). Evaluation of the Env antibody responses at 4 weeks post-boost indicated increased antibody titers to gp120 and gp41 in the HIV-1 DNA vaccinated animal as compared with the control animals. No neutralizing antibodies were detected. The rhesus macaques were challenged with SHIV-IIIb. At 4 weeks post-protein boost, the HIV-1 DNA vacine + protein immunization resulted in reduction of plasma viral RNA indicating that the animals were partially protected. Pig-tailed macaques were challenged with HIV-1. Plasma viral load analysis of the HIV-1 DNA vaccinated animals demonstrated absence of detectable virus by bDNA PCR in animals vaccinated with the CMV-HIV DNA. Studies are underway to investigate viral sequences in the PBMCs to determine whether complete protection was achieved in the DNA vaccinated animals.