合成多肽疫苗的免疫原性

合成多肽疫苗与传统疫苗相比具有纯度高、安全性好等诸多优点,但也存在一些致命的弱点,其一是免疫原性差,一般通过添加佐剂或对合成多肽进行修饰才能获得较好的免疫效果。最常用的佐剂是不完全福氏佐剂和铝佐剂,近年陆续出现了多种新型佐剂,如含皂角苷、免疫刺激复合物、CpG寡核苷酸、黏膜免疫佐剂等等。修饰多肽的经典方法是耦联蛋白质载体,其他如耦联脂质载体或脂质体、环化、支链化、多重抗原肽(MAP)、同向重复表位、加入辅助T细胞表位等方法均可获得较好的免疫效果,甚至可以不依赖佐剂。同时,优化多肽在体内的转运途径如用脂质体、可降解微球等包埋多肽也可有效地增强其免疫原性。对合成多肽疫苗设计方案进行合理优化对提升多肽免疫原性显得尤为重要。此文对提高疫苗免疫原性的佐剂与载体进行了综述。

Immunogenicity of synthetic peptide vaccine

Synthetic peptide vaccine is proven to be of high purity, good tolerance, low toxicity, etc. However, the poor immunogenicity remains an obstacle that hampers the application of this type of vaccine. The peptide immunogen could be rendered immunogenic when conjugated to carrier protein and emulsified in Freund's adjuvant. Recently, many novel types of adjuvant derived from bacterium, saponin, cytokines, etc, have been investigated to enhance immunogenicity of synthetic peptide. Besides the improvement in adjuvant, molecular modification of peptide constructs sounds to be more powerful tool in promoting immunogenicity of synthetic peptide, such as by conjugating to liposome, lipid, polymerized lysine carrier, by concatenating T helper epitope with B cell epitope, or by constructing multiple antigen peptides or tandem repeats of epitopes, etc. Other improvement has also been achieved concerning vaccine delivery systems in which liposome, microsphere, etc. acts as transport vehicle and adjuvant as well. Rational design of peptide constructs may play pivotal role on the overall immunogenicity of synthetic vaccine, which combines optimized modification of peptide construct, adjuvant and delivery vehicles. This article reviews the adjuvant and carrier protein research of synthetic peptide vaccine.