沙门氏菌的基因缺失使其毒性消失,但仍有一定侵袭力。因此,一些沙门氏菌无毒株不仅可以作为沙门氏菌的口服活疫苗,而且还可能成为表达其他细菌、病毒和寄生虫的异源性抗原的口服疫苗载体菌。口服疫苗不仅能诱导粘膜免疫和全身免疫,而且这种接种方式能适合乙型肝炎所要求的大人群免疫接种的特点,而多价、一次、口服的方式更便于采用。作者选择鼠伤寒沙门氏菌作为疫苗载体的依据是:真核细胞蛋白和病毒外膜蛋白,如乙型肝炎病毒(HBV)的HBsAg,前-S Salmonella gene deletion makes its toxicity disappear, but there is still some invasiveness. Thus, some Salmonella avirulent strains may act not only as oral live vaccine against Salmonella, but may also become oral vaccine vectors that express heterologous antigens from other bacteria, viruses and parasites. Oral vaccine can not only induce mucosal immunity and systemic immunity, and this method of vaccination can be adapted to the characteristics of the large population of hepatitis B required for immunization, and more affordable, once, more convenient oral use. The authors chose Salmonella typhimurium as a vaccine vector based on eukaryotic cellular proteins and viral outer membrane proteins such as hepatitis B virus (HBV) HBsAg, pre-S