Greenway T E, Eldridge J H, Ludwig G, Staas J K, Smith J F, Gilley R M, Michalek S M
Department of Microbiology, University of Alabama at Birmingham 35294, USA.
Vaccine. 1998 Aug;16(13):1314-23. doi: 10.1016/s0264-410x(98)00008-5.
Venezuelan equine encephalomyelitis (VEE) virus, a member of the family Togaviridae, genus Alphavirus, causes disease in humans and equids. The virus is normally transmitted by the bite of an infected mosquito however, it can also be highly infectious by aerosol. The purpose of the present study was to determine the effectiveness of formalin-fixed, 60Co-irradiated VEE virus microencapsulated in poly DL-lactide-co-glycolide in inducing immune responses protective against aerosol challenge with virulent VEE virus. Balb/c mice were primed by subcutaneous injection of microencapsulated VEE virus vaccine, followed 30 days later by a single immunization with the same vaccine given via the oral, intratracheal (i.t.) or subcutaneous (s.c.) route. Mice boosted by the i.t. or s.c. route had higher plasma IgG anti-VEE virus levels than orally immunized animals. The responses in the former groups were similar in magnitude to those seen in mice primed and boosted by the i.t. route. Antibody activity was detected in bronchial-alveolar and intestinal washes, fecal extracts and saliva from immunized animals. The levels of IgG and IgA antibody activity in bronchial-alveolar wash fluids from mice boosted by the i.t. route were higher than those seen in animals immunized by the oral or s.c. route with the microsphere vaccine. Mice immunized with the microencapsulated VEE virus vaccine were protected from lethal VEE virus infection following aerosol challenge at approximately three months after the initial immunization. Mucosal immunization via the i.t. route appeared to be the most effective regimen, since 100% of the mice resisted aerosol challenge.
委内瑞拉马脑炎（VEE）病毒是披膜病毒科甲病毒属的成员，可导致人类和马属动物患病。该病毒通常通过受感染蚊子的叮咬传播，不过，它也可通过气溶胶具有高度传染性。本研究的目的是确定用聚DL-丙交酯-乙交酯微囊化的经福尔马林固定、60钴辐照的VEE病毒在诱导针对强毒VEE病毒气溶胶攻击的保护性免疫反应方面的有效性。通过皮下注射微囊化VEE病毒疫苗对Balb/c小鼠进行初次免疫，30天后通过口服、气管内（i.t.）或皮下（s.c.）途径用同一疫苗进行单次免疫。通过i.t.或s.c.途径加强免疫的小鼠血浆中抗VEE病毒IgG水平高于口服免疫的动物。前一组的反应强度与通过i.t.途径初次免疫和加强免疫的小鼠相似。在免疫动物的支气管肺泡灌洗液、肠灌洗液、粪便提取物和唾液中检测到抗体活性。通过i.t.途径加强免疫的小鼠支气管肺泡灌洗液中的IgG和IgA抗体活性水平高于用微球疫苗经口服或s.c.途径免疫的动物。在用微囊化VEE病毒疫苗免疫的小鼠在初次免疫后约三个月受到气溶胶攻击后，可免受致命的VEE病毒感染。通过i.t.途径进行黏膜免疫似乎是最有效的方案，因为100%的小鼠抵抗气溶胶攻击。
