Wang Daqing, Christopher Mary E, Nagata Les P, Zabielski Monika A, Li Hongduo, Wong Jonathan P, Samuel John
Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB, Canada T6G 2N8.
J Clin Virol. 2004 Dec;31 Suppl 1:S99-106. doi: 10.1016/j.jcv.2004.09.013.
Influenza viral infections are a significant global public health concern due to the morbidity and mortality associated with acute respiratory disease, associated secondary complications and pandemic threat. Currently, the most effective preventative measure is an annual intramuscular (i.m.) injection of a trivalent vaccine. Intramuscular immunization induces strong systemic humoral responses but not mucosal immune responses which are important in the first line of defense against influenza.
A plasmid encoding influenza A/PR/8/34 (H1N1) hemagglutinin (HA; pCI-HA10) was evaluated with respect to the mucosal, cellular and humoral immune responses generated and to its efficacy in protection against a challenge with a lethal dose of influenza.
BALB/c mice were immunized with pCI-HA10 DNA or liposome-encapsulated pCI-HA10 by either an intranasal (i.n.) or i.m. route. Sera and bronchoalveolar lavage (BAL) fluid were collected at various times and evaluated for HA-specific IgG and IgA antibodies and T cells, isolated from draining lymph nodes and spleens, were analyzed for their proliferative ability. Immunized mice were challenged with a lethal dose (5LD(50)) of influenza and monitored for survival.
Intranasal immunization with liposome-encapsulated pCI-HA10 stimulated both IgG and IgA humoral responses and increased IgA titers in BAL fluid, whereas immunization with naked pCI-HA10 had no effect on the antibody response. Intramuscular immunization with both naked and liposome-encapsulated pCI-HA10 elevated serum IgG levels, but had no effect on IgA levels in either the serum or BAL fluid. Both i.n. and i.m. administration of HA vaccine (naked and liposome-encapsulated) elicited T cell proliferative responses. These results suggest that i.n. administration of liposome-encapsulated HA-encoding DNA is effective at eliciting mucosal, cellular and humoral immune responses. Mice immunized i.n. were able to withstand a lethal challenge of influenza virus, confirming that the immune responses mediated by the vaccine were protective.
由于与急性呼吸道疾病相关的发病率和死亡率、相关的继发性并发症以及大流行威胁，流感病毒感染是一个重大的全球公共卫生问题。目前，最有效的预防措施是每年进行一次三价疫苗的肌肉注射。肌肉免疫诱导强烈的全身体液反应，但不诱导黏膜免疫反应，而黏膜免疫反应在抵御流感的第一道防线中很重要。
评估编码甲型流感病毒/PR/8/34（H1N1）血凝素（HA；pCI-HA10）的质粒在产生黏膜、细胞和体液免疫反应方面以及在抵御致死剂量流感病毒攻击中的功效。
通过鼻内（i.n.）或肌肉注射（i.m.）途径，用pCI-HA10 DNA或脂质体包裹的pCI-HA10对BALB/c小鼠进行免疫。在不同时间收集血清和支气管肺泡灌洗（BAL）液，并评估HA特异性IgG和IgA抗体，对从引流淋巴结和脾脏分离的T细胞进行增殖能力分析。用致死剂量（5LD50）的流感病毒攻击免疫的小鼠，并监测其存活情况。
用脂质体包裹的pCI-HA10进行鼻内免疫刺激了IgG和IgA体液反应，并增加了BAL液中的IgA滴度，而用裸pCI-HA10免疫对抗体反应没有影响。用裸pCI-HA10和脂质体包裹的pCI-HA10进行肌肉免疫均提高了血清IgG水平，但对血清或BAL液中的IgA水平没有影响。HA疫苗（裸疫苗和脂质体包裹疫苗）的鼻内和肌肉注射给药均引发了T细胞增殖反应。这些结果表明，鼻内给予脂质体包裹的编码HA的DNA在引发黏膜、细胞和体液免疫反应方面是有效的。经鼻内免疫的小鼠能够抵御流感病毒的致死攻击，证实了疫苗介导的免疫反应具有保护作用。
