Somroop Srinuan, Tongtawe Pongsri, Chaisri Urai, Tapchaisri Pramuan, Chongsa-nguan Manas, Srimanote Potjanee, Chaicumpa Wanpen
Faculty of Allied Health Sciences, Thammasat University, Rangsit Center, Pathumthani, Thailand.
Asian Pac J Allergy Immunol. 2006 Dec;24(4):229-38.
An oral cholera vaccine made up of heat-treated recombinant cholera toxin (rCT), V. cholerae lipopolysaccharide (LPS), and recombinant toxin-co-regulated pili subunit A (rTcpA), entrapped in liposomes in the presence of unmethylated bacterial CpG-DNA (ODN#1826) was used to orally immunize a group of eight week old rats. A booster dose was given 14 days later. Control rats received placebo (vaccine diluent). The kinetics of the immune response were investigated by enumerating the antigen specific-antibody secreting cells (ASC) in the blood circulation and intestinal lamina propria using the ELISPOT assay and a histo-immunofluorescence assay (IFA), respectively. ASC of all antigenic specificities were detected in the blood of the vaccinated rats as early as two days after the booster dose. The numbers of LPS-ASC and TcpA-ASC in the blood were at their peak at day 3 post booster while the number of CT-ASC was highest at day 4 after the booster immunization. At day 13 post immunization, no ASC were detected in the blood. A several fold increase in the number of ASC of all antigenic specificities in the lamina propria above the background numbers of the control animals were found in all vaccinated rats at days 6 and 13 post booster (earlier and later time points were not studied). Vibriocidal antibody and specific antibodies to CT, LPS and TcpA were detected in 57.1% and 52.4%, 14.3%, and 19.0% of the orally vaccinated rats, respectively. The data indicated that rats orally primed with the vaccine could produce a rapid anamnestic response after re-exposure to the V. cholerae antigens. Thus, a single dose of the vaccine is expected to elicit a similar anamnestic immune response in people from cholera endemic areas who have been naturally primed to V. cholerae antigens, while two doses at a 14 day interval should be adequate for a traveler to a disease endemicarea.
一种口服霍乱疫苗，由经热处理的重组霍乱毒素（rCT）、霍乱弧菌脂多糖（LPS）和重组毒素共调节菌毛亚基A（rTcpA）组成，在未甲基化的细菌CpG-DNA（ODN#1826）存在的情况下包裹于脂质体中，用于口服免疫一组8周龄大鼠。14天后给予加强剂量。对照大鼠接受安慰剂（疫苗稀释剂）。分别使用ELISPOT测定法和组织免疫荧光测定法（IFA），通过计数血液循环和肠固有层中的抗原特异性抗体分泌细胞（ASC）来研究免疫反应的动力学。早在加强剂量后两天，在接种疫苗大鼠的血液中就检测到了所有抗原特异性的ASC。血液中LPS-ASC和TcpA-ASC的数量在加强后第3天达到峰值，而CT-ASC的数量在加强免疫后第4天最高。免疫后第13天，血液中未检测到ASC。在加强后第6天和第13天（未研究更早和更晚的时间点），所有接种疫苗的大鼠固有层中所有抗原特异性的ASC数量均比对照动物的背景数量增加了数倍。在口服接种疫苗的大鼠中，分别有57.1%、52.4%、14.3%和19.0%检测到了杀弧菌抗体以及针对CT、LPS和TcpA的特异性抗体。数据表明，用该疫苗进行口服初免的大鼠在再次接触霍乱弧菌抗原后可产生快速的回忆反应。因此，单剂量疫苗有望在自然接触过霍乱弧菌抗原的霍乱流行地区人群中引发类似的回忆免疫反应，而间隔14天接种两剂疫苗对于前往疾病流行地区的旅行者应该足够。
