Immunogenicity of plant-expressed p55 Gag and gp120

描述（由申请方提供）：开发有效的全球HIV疫苗面临的障碍分为几类。第一，缺乏对感染或疾病产生长期保护的HIV/SIV/SHIV疫苗制剂，第二，高成本和复杂的输送系统将排除在发展中国家使用甚至是成功的疫苗。强大的细胞CD 8+介导的免疫应答，直到最近，似乎保护接种疫苗的猕猴免受艾滋病，最近已被证明是由病毒CTL逃逸突变体中的单突变妥协，并说明需要更广泛的免疫应答和中和抗体作为第二层防御的重要性，在急性和慢性感染。 该“概念验证”建议旨在通过利用廉价且充分表征的植物表达系统来解决这些限制中的几个，以便1）生产和测试植物来源的SHIV/HIV蛋白的免疫原性，其既作为潜在的可注射疫苗候选物，又用于基础研究以阐明中和抗体的诱导，和2）长期，以适应植物衍生蛋白的免疫原性潜力，作为开发廉价且易于施用的可食用疫苗的第一步。具体地，（i）将评估植物来源的SIV 239 p55 Gag蛋白在gag引发的猕猴加强后诱导强病毒特异性T细胞应答的能力，（ii）将在豚鼠和猕猴中评估HIV 89.6 gp 120糖蛋白的变体形式引发/阻断中和抗体的能力，具有不同糖基化谱的gp 120分子将通过使用将蛋白质靶向植物细胞中不同区室的信号序列来产生，和（iii）猕猴将用Gag加上最佳形式/在佐剂中乳化的gp 120的s，以测量gag/env质粒DNA致敏的猕猴中的细胞和体液免疫。如果成功，这些猕猴将在第II阶段接受SHIV攻毒。在整个研究的每个方面，植物表达的蛋白质将与其他表达系统中产生的蛋白质以及它们与充分表征的中和抗体结合的能力进行比较。

DESCRIPTION (provided by applicant): Obstacles facing the development of a efficacious global HIV vaccine/s fall into several categories. Firstly, the absence of HIV/SIV/SHIV vaccine formulations that elicit long term protection against either infection or disease and secondly, the high cost and complex delivery systems that will preclude the use of even successful vaccines in developing countries. Robust cellular CD8+ mediated immune responses which, until recently, appeared to protect vaccinated macaques from AIDS, have recently been shown to be compromised by single mutations in viral CTL escape mutants and illustrate the requirment for broader immune responses and the importance of neutralizing antibody as a second layer of a defense in acute and chronic infections. This "proof of concept" proposal aims to address several of these limitations by utilizing an inexpensive and well characterized plant expression system in order 1) to produce and test the immunogenicity of plant-derived SHIV/HIVproteins both as potential injectable vaccine candidates and for use in basic research to elucidate the induction of neutralizing antibody and 2) long term, to adapt the immunogenic potential of plant-derived proteins as a first step towards the development of a cheap and easily administered edible vaccine. Specifically, (i) plant-derived SIV 239 p55 Gag protein will be assessed for its ability to induce strong virus specific T cell responses following boosting of gag-primed macaques (ii) variant forms of the HIV 89.6 gp120 glycoprotein, will be assessed in guinea pigs and macaques for their ability to elicit/block neutralizing antibodies, gp120 molecules with different glycosylation profiles will be produced by using signal sequences which target proteins to different compartments in the plant cells and (iii) macaques will be boosted with both Gag plus the optimal form/s of gp120 emulsified in adjuvant to measure cellular and humoral immunity in gag/env plsmid DNA-primed macaques. If successful these macaques will be challenge with SHIV in Phase II. Throughout each aspect of the study, plant-expressed proteins will be compared with proteins produced in other expression systems as well as their ability to bind to well characterized neutralizing antibodies.