菌影（bacterial ghost，BG）是由噬菌体ΦX174 E基因表达蛋白介导革兰阴性菌裂解所形成的空胞，无胞质内容物，但保留了天然的胞壁结构。由于BG具有颗粒特性并含有天然表面抗原组分，因此易于被抗原呈递细胞识别并激发体液和细胞免疫应答。BG可负载外源蛋白和DNA，并可通过各种免疫途径进行接种。因此，BG是一种有潜力的疫苗递送系统。

Bacterial ghosts（BGs）are empty cell envelopes of Gram-negative bacteria, which are produced by controlled expression of cloned gene E of bacteriophage ΦX174 and protein E-mediated lysis. BGs are devoid of cytoplasmic contents and retains native cell wall structures. As BGs have the particulate nature and contain native surface antigenic components, they can be easily recognized by antigen presenting cells and stimulate humoral and cellular immune responses. BGs can be loaded with foreign proteins and DNA, and administrated through various immunization routes. Therefore, BG is a potential vaccine delivery system.