Periolo O H, Seki C, Grigera P R, Robiolo B, Fernández G, Maradei E, D'Aloia R, La Torre J L
Centro de Virología Animal (CEVAN-CONICET), Buenos Aires, Argentina.
Vaccine. 1993;11(7):754-60. doi: 10.1016/0264-410x(93)90261-u.
Specific serum activity levels against four reference strains of foot-and-mouth disease virus (FMDV) were evaluated from 1634 animals vaccinated with commercial quadrivalent oil vaccines and from 746 unvaccinated, naive animals, using the liquid-phase blocking sandwich ELISA (lpELISA) test. Cows from the FMDV-free area of Argentina were tested for the absence of specific FMDV antibodies (sp FMDV Abs) and those showing lpELISA titres < 1.0 were grouped in lots of 16 animals. They were vaccinated and challenged at 90 days postvaccination (DPV) with one of four virus strains used for vaccine production and control (prototype strains). Serum samples from vaccinated and control cattle were collected 60 and 90 DPV and the level of sp FMDV Abs was determined by lpELISA. Animals were examined for clinical signs of disease. Results show that serum lpELISA titre levels directly correlate with the percentage of protected animals. It was seen that 100, 98, 93 and 87% of the vaccinated cattle with antibody titre levels > or = 2.1 were protected against challenge with serotypes C85, A87,01 Cas and A79, respectively. Evidence is also presented of seroconversion in a sample of 3-5-month-old calves vaccinated in the field, showing lpELISA titres compatible with protection against the four vaccine viruses as long as 150 DPV. Results reported in this paper strongly support the use of the lpELISA test for a rapid and reliable evaluation of the efficacy of FMDV commercial vaccines as well as for the assessment of the immunological status of cattle in FMDV-free and enzootic regions of South America.
使用液相阻断夹心酶联免疫吸附测定（lpELISA）试验，对1634头接种了商用四价油佐剂疫苗的动物以及746头未接种疫苗的未接触过口蹄疫病毒（FMDV）的动物，评估了针对四种口蹄疫病毒参考毒株的特异性血清活性水平。对来自阿根廷无口蹄疫病毒地区的奶牛进行检测，以确定是否存在特异性口蹄疫病毒抗体（sp FMDV Abs），将那些lpELISA滴度<1.0的奶牛按16头一组进行分组。在接种疫苗后90天（DPV），用用于疫苗生产和对照的四种病毒毒株之一（原型毒株）对它们进行接种并攻毒。在接种疫苗后60天和90天收集接种疫苗和对照牛的血清样本，并通过lpELISA测定sp FMDV Abs的水平。检查动物是否有疾病的临床症状。结果表明，血清lpELISA滴度水平与受保护动物的百分比直接相关。可以看到，抗体滴度水平≥2.1的接种疫苗的牛，分别有100%、98%、93%和87%受到保护，免受C85、A87、O1 Cas和A79血清型病毒的攻毒。还提供了在田间接种疫苗的3至5月龄犊牛样本中血清转化的证据，显示lpELISA滴度与针对四种疫苗病毒的保护作用相符，长达150 DPV。本文报道的结果有力地支持了使用lpELISA试验快速可靠地评估口蹄疫病毒商用疫苗的效力，以及评估南美洲无口蹄疫病毒地区和流行地区牛的免疫状态。
