Saravanan Paramasivam, Sreenivasa B P, Selvan R P Tamil, Basagoudanavar Suresh H, Hosamani Madhusudan, Reddy Nandakumar D, Nathanielsz J, Derozier Christophe, Venkataramanan Ramamurthy
Indian Veterinary Research Institute, Hebbal, Bangalore 560024, India.
Zoetis VMRD Asia Pacific, 333 Portage Street, MS 300-420.21SW, Kalamazoo, MI 49007, USA.
Vaccine. 2015 Jan 29;33(5):670-7. doi: 10.1016/j.vaccine.2014.12.008. Epub 2014 Dec 17.
Foot-and-mouth disease (FMD) vaccines applied for prophylactic use in endemic areas provide short-lived immunity requiring regular boosters. Indian FMD control program recommends twice a year vaccination. Development of high potency vaccines that provide better immune response can singificantly contribute to control programme by reducing the frequency of vaccination. The present study explores new adjuvants to enhance the protective efficacy of inactivated trivalent FMD vaccines.
VacciMax(®) is a novel adjuvant which uses a liposome-based oil emulsion platform. Cattle were immunized using VacciMax-A and VacciMax-B FMD vaccines and evaluated for protective efficacy. Similar groups of animals were also boosted after 6 months to study the effect of booster immunisation on protection against homologous challenge. Serum samples from immunized animals were tested by virus neutralization test (VNT) and liquid phase blocking ELISA (LPBE). After challenge, animals were screened for virus load by real-time PCR and reactivity in non-structural protein (3ABC) antibody detection ELISA to corroborate the protection data. A single dose of VacciMax-A formulation elicited higher percentage protection (63%) in VacciMax-A compared to 25% in VacciMax-B upon challenge at one-year post-vaccination. Upon boosting at 6 months also, VacciMax-A group showed higher levels of protection (100%) compared to VacciMax-B (86%), even though both the groups elicited comparable VNT titre (p=0.4964). The results also demonstrated that intramuscular route was preferrable over subcutaneous route of administration.
The study demonstrates that immunization with VacciMax-A-IM adjuvanted FMD vaccine with high antigen payload under boosting regimen could effectively be used as potent vaccine to maintain herd immunity.
在流行地区用于预防的口蹄疫（FMD）疫苗提供的免疫力持续时间较短，需要定期加强免疫。印度口蹄疫防控计划建议每年接种两次疫苗。开发能提供更好免疫反应的高效疫苗，可通过减少接种频率为防控计划做出重大贡献。本研究探索新型佐剂以增强灭活三价口蹄疫疫苗的保护效力。
VacciMax(®)是一种新型佐剂，采用基于脂质体的油乳剂平台。使用VacciMax-A和VacciMax-B口蹄疫疫苗对牛进行免疫，并评估其保护效力。6个月后对相似组别的动物进行加强免疫，以研究加强免疫对抵抗同源攻击的保护作用。通过病毒中和试验（VNT）和液相阻断ELISA（LPBE）检测免疫动物的血清样本。攻击后，通过实时PCR筛选动物的病毒载量，并在非结构蛋白（3ABC）抗体检测ELISA中检测反应性，以证实保护数据。在接种疫苗一年后进行攻击时，单剂量的VacciMax-A制剂在VacciMax-A组中引发的保护率更高（63%），而VacciMax-B组为25%。在6个月时进行加强免疫后，VacciMax-A组的保护水平也高于VacciMax-B组（100%对86%），尽管两组引发的VNT滴度相当（p=0.4964）。结果还表明，肌肉注射途径优于皮下注射途径。
该研究表明，在加强免疫方案下，用高抗原含量的VacciMax-A-IM佐剂口蹄疫疫苗进行免疫，可有效用作高效疫苗以维持畜群免疫力。
