Liu Gui-xia, Lan Jia-ming, Chuai Xia, Gao Zhi-yun, Jin Yu-huai, Zhang Yong-hong, Xie Li-xin, Yin Chang-fu, Wang Yong-xiang
Department of Pathogenic Biology, Hebei Medical University, Shijiazhuang, China.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi. 2010 Feb;26(2):103-6.
To compare the immunogenicity and protective effects on CVB3 infected mice of four DNA fusion vaccines coupling coxsackievirus B3 (CVB3) VP1 with macrophage-derived chemokine (MDC), C3d3, shiga toxin B subuit (STxB) and mouse beta-defensin-2 (mBD2), respectively.
BALB/c mice were divided into 6 groups randomly and inoculated in quadriceps at 3-week interval for 3 times with pcDNA3, pcDNA3/VP1, pcDNA3/MDC-VP1, pcDNA3/VP1-C3d3, pcDNA3/STxB-VP1 and pcDNA3/mBD2 -VP1, respectively. Fourteen days after every inoculation, serum samples were collected and CVB3 specific neutralizing antibodies were determined. Three weeks after the last immunization, the mice were treated in three ways. First, the spleen cells were isolated from 3 mice of each group and specific CTL activities were tested. Second, 3 mice of each group were further challenged with 3LDLD(50); CVB3 and sacrificed 7 days later, and their blood viral titers were evaluated. Third, the rest mice of each group were subjected to intraperitoneal (i.p.) challenge with 5LDLD(50); CVB3 and their survival was observed.
The neutralizing antibodies against CVB3 were induced in pcDNA3/VP1, pcDNA3/MDC-VP1, pcDNA3/VP1-C3d3, pcDNA3/STxB-VP1 and pcDNA3/mBD2 -VP1 groups, and antibody titers correlated with the number of injections (P<0.01). After three immunizations, the antibody titers in pcDNA3/MDC-VP1, pcDNA3/VP1-C3d3 and pcDNA3/mBD2 -VP1 groups were higher than the ones in pcDNA3/VP1and pcDNA3/STxB-VP1 groups (P<0.01). The specific CTL activities in both pcDNA3/STxB-VP1 and pcDNA3/mBD2-VP1 groups were significantly stronger than those in the other groups (P<0.01). After CVB3 challenge, the blood viral titers in the pcDNA3/MDC-VP1, pcDNA3/VP1-C3d3 and pcDNA3/mBD2-VP1 groups were lower than those in the other groups (P<0.01), and the pcDNA3/MDC-VP1 and pcDNA3/VP1-C3d3 mice survived longer than the others (P<0.05).
Both pcDNA3/MDC-VP1 and pcDNA3/VP1-C3d3 vaccines could induce stronger immune responses, resulting in higher survival rates and better protective effects on CVB3 infection than pcDNA3/STxB-VP1, pcDNA3/mBD2-VP1 and pcDNA3/VP1 vaccines.
比较分别将柯萨奇病毒B3（CVB3）VP1与巨噬细胞衍生趋化因子（MDC）、C3d3、志贺毒素B亚基（STxB）和小鼠β-防御素-2（mBD2）偶联的四种DNA融合疫苗对CVB3感染小鼠的免疫原性和保护作用。
将BALB/c小鼠随机分为6组，分别用pcDNA3、pcDNA3/VP1、pcDNA3/MDC-VP1、pcDNA3/VP1-C3d3、pcDNA3/STxB-VP1和pcDNA3/mBD2-VP1于股四头肌每隔3周接种1次，共接种3次。每次接种14天后，采集血清样本并测定CVB3特异性中和抗体。末次免疫3周后，对小鼠进行三种处理。第一，从每组3只小鼠中分离脾细胞并检测特异性CTL活性。第二，每组3只小鼠进一步用3LD50的CVB3攻击，7天后处死，评估其血液病毒滴度。第三，每组其余小鼠用5LD50的CVB3进行腹腔注射攻击，观察其存活情况。
pcDNA3/VP1、pcDNA3/MDC-VP1、pcDNA3/VP1-C3d3、pcDNA3/STxB-VP1和pcDNA3/mBD2-VP1组均诱导出针对CVB3的中和抗体，抗体滴度与注射次数相关（P<0.01）。三次免疫后，pcDNA3/MDC-VP1、pcDNA3/VP1-C3d3和pcDNA3/mBD2-VP1组的抗体滴度高于pcDNA3/VP1和pcDNA3/STxB-VP1组（P<0.01）。pcDNA3/STxB-VP1和pcDNA3/mBD2-VP1组的特异性CTL活性均显著强于其他组（P<0.01）。CVB3攻击后，pcDNA3/MDC-VP1、pcDNA3/VP1-C3d3和pcDNA3/mBD2-VP1组的血液病毒滴度低于其他组（P<0.01），且pcDNA3/MDC-VP1和pcDNA3/VP1-C3d3组小鼠的存活时间长于其他组（P<0.05）。
与pcDNA3/STxB-VP1、pcDNA3/mBD2-VP1和pcDNA(3)/VP1疫苗相比，pcDNA3/MDC-VP1和pcDNA3/VP1-C3d3疫苗均可诱导更强的免疫反应，从而对CVB3感染具有更高的存活率和更好的保护作用。
