Yan Meiying, Liu Guangwen, Diao Baowei, Qiu Haiyan, Zhang Lijuan, Liang Weili, Gao Shouyi, Kan Biao
State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, PR China.
Vaccine. 2007 May 16;25(20):4046-55. doi: 10.1016/j.vaccine.2007.02.043. Epub 2007 Mar 5.
Cholera is a severe diarrheal disease that may spread rapidly. Vaccination is considered a valid measure against it. We developed a new vaccine candidate, IEM109, against Vibrio cholerae. To generate this candidate, a chromosomal fragment containing the TLC element, attB of the CTX Phi integration site, and RTX cluster responsible for the cytotoxic activity for mammalian cells was deleted through homologous recombination from the previously described El Tor biotype, IEM101. The protective genes ctxB and rstR, which establish resistance to CTX Phi infections, were inserted into that same location on the chromosome of IEM109 to enhance the safety and genetic stability of the vaccine candidate and to prevent horizontal gene transfer. In in vivo tests, cell cultures showed that the cytotoxic effect of IEM109 on Hep-2 was negative. Furthermore, the infection rate of El Tor biotype CTX Phi to that of IEM109 in the rabbit intestine is 3000-fold lower than that of IEM101. Intraintestinal vaccination of rabbits with a single dose of IEM109 elicits high titers of anti-CTB IgG and vibriocidal antibodies. When challenged with 0.5-2 microg CT and 10(5) to 10(8)CFU of four wild toxigenic strains of different biotypes and serogroups, IEM109 conferred full protection. Thus, IEM109 is a stable vaccine candidate that evokes not only antitoxic and vibriocidal immunities, but also resistance to the El Tor biotype CTX Phi infection.
霍乱是一种可能迅速传播的严重腹泻疾病。疫苗接种被认为是预防霍乱的有效措施。我们研发了一种针对霍乱弧菌的新型候选疫苗IEM109。为了制备该候选疫苗，通过同源重组从先前描述的埃尔托生物型IEM101中删除了包含TLC元件、CTX Φ整合位点的attB以及负责对哺乳动物细胞产生细胞毒性活性的RTX簇的染色体片段。将对CTX Φ感染产生抗性的保护性基因ctxB和rstR插入到IEM109染色体的同一位置，以提高候选疫苗的安全性和遗传稳定性，并防止水平基因转移。在体内试验中，细胞培养显示IEM109对Hep-2细胞的细胞毒性作用为阴性。此外，埃尔托生物型CTX Φ在兔肠道中对IEM109的感染率比IEM101低3000倍。用单剂量IEM109对兔进行肠道内接种可引发高滴度的抗CTB IgG和杀弧菌抗体。当用0.5 - 2微克霍乱毒素以及10^5至10^8 CFU的四种不同生物型和血清群的野生产毒菌株进行攻毒时，IEM109提供了完全保护。因此，IEM109是一种稳定的候选疫苗，它不仅能引发抗毒素和杀弧菌免疫，还能抵抗埃尔托生物型CTX Φ感染。
