Immunogenicity of an HIV virus-like particle vaccine

虽然艾滋病被发现只有20年的时间，但全球已有近6000万人感染了人类免疫缺陷病毒，目前其中3600万人感染了艾滋病毒。控制这种毁灭性疾病的最有效方法是开发一种安全、实用和有效的疫苗，既可以防止新的感染，也可以减缓疾病的进展。最近的研究表明，这种疫苗既需要体液免疫，也需要细胞免疫。DNA启动和重组痘苗病毒Boost是一种很有前途的方法。我们开发了一种新的基于DNA的双重塞姆利基森林病毒(SFV)表达系统。SFV载体同时表达密码子使用优化的gag和env基因。 细胞中病毒样颗粒(VLP)的形式。结合SFV载体的高表达特性和优化的HIV-1基因，我们预计在自然病毒构象中高水平表达的病毒蛋白将在动物中激发中和抗体和CTL反应。现在，我们提议评估新开发的独特DNA疫苗候选在豚鼠和小鼠身上对HIV特异性体液和细胞免疫反应的影响。这些动物将在体内单独用DNA免疫以产生VLP，然后用自体rgpl20或表达自体Gag或env基因的重组痘苗病毒加强免疫。我们将收集豚鼠的血清样本，以确定同时表达gag和env基因的sfv载体是否会激发更高滴度的中和抗体，以及体液免疫反应是否可以。 Rgpl20或表达env基因的重组痘苗病毒可进一步扩增。我们还将分离免疫小鼠的脾细胞，以确定我们新开发的双表达SFV载体产生的VLP是否可以单独或与重组痘苗病毒Boost一起诱导强大的CTL反应，VLP是否可以同时诱导CD4和CD8反应，以及VLP是否可以比单独的Gag或env基因诱导更好和更广泛的CTL反应。这项研究的结果将确定双表达SFV载体在体内产生的VLP能否发展成为有效的艾滋病疫苗，并用作指导在小鼠和豚鼠或更高水平的动物(如猴子)中设计更好的免疫策略。

Although AIDS has only been identified for 20 years, nearly 60 million people have been infected with human immunodeficiency viruses globally and currently 36 million of them are living with HIV infection. The most effective way to control the devastating disease is to develop a safe, practical, and effective vaccine that can either prevent new infection or slow down disease progression. Recent studies showed that both humoral and cellular immune responses are needed for such a vaccine. DNA prime and recombinant vaccinia virus boost exhibit a promising approach. We have developed a new DNA based dual semliki forest virus (SFV) expression system. The SFV vector expresses both codon-usage optimized gag and env genes in the form of virus-like particles (VLP) from the cells. Coupled with high expression nature of SFV vector and optimized HIV-1 genes, we expect high expression level of viral proteins in natural viral conformation will elicit both neutralizing antibody and CTL responses in animals. Now we are proposing to evaluate the newly developed unique DNA vaccine candidate in guinea pigs and mice for HIV specific humoral and cellular immune responses. The animals will be immunized with DNA alone for production of VLP in vivo and then boosted with either autologous rgpl20 or recombinant vaccinia viruses expressing autologous gag or env genes. We will collect serum samples from guinea pigs to determine if higher titers of neutralizing antibody will be elicited by the SFV vector that express both gag and env genes, and if humoral immune response can be further augmented by either rgpl20 or recombinant vaccinia virus that expresses env gene. We will also isolate the splenocytes from immunized mice to determine if VLPs generated by our newly developed dual expression SFV vector can induce strong CTL response alone or with recombinant vaccinia virus boost, if both CD4 and CD8 responses will be induced by VLPs, and if VLPs can induce better and broader CTL responses than either the gag or env gene alone. Results from this study will determine if VLPs generated by dual expression SFV vector in vivo can bc developed into an effective AIDS vaccine and used as a guideline to design better immunization strategies in mice and guinea pigs or higher level animals, like monkeys.