Gómez-Morales Maria Angeles, Ludovisi Alessandra, Amati Marco, Pozio Edoardo
Department of Infectious, Parasitic and Immunomediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
Department of Infectious, Parasitic and Immunomediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
Vet Parasitol. 2015 Mar 15;208(3-4):218-24. doi: 10.1016/j.vetpar.2015.01.012. Epub 2015 Jan 24.
Serology to monitor Trichinella spp. infection in pigs reared in controlled system has been claimed as a possible diagnostic tool. However, no international biological standards or reference materials exist to validate in house tests or commercial kits, and to improve the inter-laboratory comparability for the serological detection of anti-Trichinella IgG in pigs. In this work, potential reference sera have been prepared from four experimentally infected pigs. Sera were tested, aliquot, lyophilized, and maintained at +4°C. Since one of the prerequisites for the development of any reference material is to plan and execute stability studies, isochronous studies for short and long term stability testing were carried out to evaluate the possible degradation effects of transportation and storage. The stability of the lyophilized serum samples at +4°C, was arbitrarily assumed. For the short term stability study, two units were stored at -20°C, +4°C, +20°C, and +50°C for 0, 1, 2, and 4 weeks, and then tested in duplicate. For the long term stability study, the same number of units and replicates per unit were stored at -80°C, -20°C, and +4°C for 0, 6, 12, 18 and 24 months. In both studies, unit samples were selected randomly and tested on the same day under repeatability conditions. The linear regression versus time for each serum at each studied temperature was analyzed and then slopes were tested for significance. Further, uncertainty of the short and long term stability was calculated for a shelf life period of one week and three years, respectively. For all sera but one, and for all the studied temperatures but +50°C, the data from the short term stability study indicate the absence of a significant trend that would hint at degradation. The slopes of the regression lines did not significantly vary from zero. Even if the uncertainty of the short term stability was variable among serum samples, the rate of degradation was considered acceptable. For the long term stability, slopes of the regression lines of two serum samples significantly varied from zero, indicating a trend of possible degradation during storage. The percentage of degradation deducted from the uncertainty of the long term study varied; however, two serum samples showed the lower rate of degradation at all the assayed temperatures. The most suitable temperatures for dispatching serum samples are -20°C, +4°C and +20°C; whereas, -20°C and -80°C are suitable temperatures for serum storage.
血清学检测被认为是监测封闭式养殖系统中猪旋毛虫感染情况的一种可能的诊断工具。然而，目前尚无国际生物标准或参考物质来验证内部检测或商业试剂盒，也无法提高猪抗旋毛虫IgG血清学检测的实验室间可比性。在这项研究中，从4头实验感染的猪身上制备了潜在的参考血清。对血清进行检测、分装、冻干，并保存在4°C环境下。由于开发任何参考物质的前提之一是规划并进行稳定性研究，因此进行了短期和长期稳定性测试的同步研究，以评估运输和储存可能产生的降解影响。冻干血清样本在4°C下的稳定性是任意假定的。短期稳定性研究中，将两个样本分别储存在-20°C、4°C、20°C和50°C下0、1、2和4周，然后进行重复测试。长期稳定性研究中，将相同数量的样本及每个样本的重复样本分别储存在-80°C、-20°C和4°C下0、6、12、18和24个月。在两项研究中，随机选择样本单元，并在同一天的重复性条件下进行测试。分析每个血清在每个研究温度下随时间的线性回归，然后检验斜率的显著性。此外，分别计算了保质期为一周和三年的短期和长期稳定性的不确定度。对于除一份血清外的所有血清，以及除50°C外的所有研究温度，短期稳定性研究的数据表明不存在暗示降解的显著趋势。回归线的斜率与零无显著差异。即使短期稳定性的不确定度在血清样本间存在差异，但降解速率被认为是可接受的。对于长期稳定性，两份血清样本的回归线斜率与零有显著差异，表明储存期间可能存在降解趋势。从长期研究的不确定度中推算出的降解百分比各不相同；然而，两份血清样本在所有测定温度下显示出较低的降解速率。血清样本最适合的分发温度为-20°C、4°C和20°C；而-20°C和-80°C是血清储存的适宜温度。
