Morrill J C, Carpenter L, Taylor D, Ramsburg H H, Quance J, Peters C J
US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21701-5011.
Vaccine. 1991 Jan;9(1):35-41. doi: 10.1016/0264-410x(91)90314-v.
A previous study demonstrated that a mutagen-attenuated Rift Valley fever virus (RVFV) vaccine, RVF MP-12, was immunogenic and non-abortogenic when ewes, 90-110 days pregnant, were inoculated with 5 x 10(5) plaque-forming units (p.f.u.) of the virus strain. The ewes delivered live, healthy lambs that had no neutralizing antibody to RVFV until after they had ingested colostrum. To assess further the safety and protective capability of this candidate vaccine, six pregnant ewes were inoculated with 5 x 10(3) p.f.u. of RVF MP-12 and challenged with 5 x 10(5) p.f.u. of virulent ZH-501 strain of RVFV 30 days later. No viraemia was detected after vaccination or challenge and all six ewes delivered live, healthy lambs. Those lambs tested before their nursing did not have neutralizing antibody to RVFV but quickly acquired antibody titres of 1:320 to greater than or equal to 1:10,240 after ingesting colostrum. To test the safety of the RVF MP-12 immunogen in neonates, lambs less than or equal to 7 days old, born to unvaccinated ewes, were inoculated with 5 x 10(5) p.f.u. of RVF MP-12. With the exception of brief pyrexia in 18 of 26 lambs, and a transient low-titred viraemia in 16 of 26 lambs after inoculation, no untoward effects were observed. Serum-neutralizing antibody to RVFV was detected 5-7 days after inoculation. Lambs vaccinated with either 5 x 10(5) or 5 x 10(3) p.f.u. of RVF MP-12 were protected against virulent RVFV challenge at 14 days postvaccination.
先前的一项研究表明，一种诱变减毒裂谷热病毒（RVFV）疫苗RVF MP - 12，在给怀孕90 - 110天的母羊接种5×10⁵空斑形成单位（p.f.u.）该病毒株时，具有免疫原性且不会引起流产。这些母羊产下了健康的活羔羊，这些羔羊在摄入初乳之前对RVFV没有中和抗体。为了进一步评估这种候选疫苗的安全性和保护能力，6只怀孕母羊接种了5×10³ p.f.u.的RVF MP - 12，并在30天后用5×10⁵ p.f.u.的强毒RVFV ZH - 501株进行攻击。接种疫苗或攻击后均未检测到病毒血症；所有6只母羊都产下了健康的活羔羊。那些在吃奶前检测的羔羊对RVFV没有中和抗体，但在摄入初乳后迅速获得了1:320至大于或等于1:10240的抗体滴度。为了测试RVF MP - 12免疫原对新生儿的安全性，给未接种疫苗的母羊所生的7日龄及以下羔羊接种5×10⁵ p.f.u.的RVF MP - 12。除了26只羔羊中有18只出现短暂发热，以及26只羔羊中有16只在接种后出现短暂的低滴度病毒血症外，未观察到其他不良影响。接种后5 - 7天检测到针对RVFV的血清中和抗体。接种5×10⁵或5×10³ p.f.u. RVF MP - 12的羔羊在接种后14天对强毒RVFV攻击具有保护作用。
