Goodman Christin, Powers Jordan A, Mikula Sierra R, Hughes Holly R, Biggerstaff Brad J, Fitzpatrick Kelly, Panella Amanda J, Machain-Williams Carlos, Lee SeungHwan, Calvert Amanda E
Division of Vector-Borne Diseases, U.S. Centers for Disease Control and Prevention, Fort Collins, Colorado.
Unidad Profesional Interdisciplinaria de Ingeniería Palenque (UPIIP), Instituto Politécnico Nacional, Palenque, Mexico.
Am J Trop Med Hyg. 2024 Nov 19;112(2):386-395. doi: 10.4269/ajtmh.24-0360. Print 2025 Feb 5.
Cache Valley virus (CVV), a mosquito-borne orthobunyavirus, causes epizootics in ruminants characterized by congenital malformations and fetal death in North America. Only seven human infections have been identified; limited information exists on its potential as a human teratogen. Diagnosis of CVV infections relies on the plaque reduction neutralization test (PRNT), which requires live virus, is time-consuming, and cannot differentiate between recent and past infections. To improve diagnostics for CVV, we developed an IgM antibody capture ELISA (MAC-ELISA) for detection of anti-CVV human IgM in diagnostic specimens that can be performed faster than PRNT and is specific to IgM, which is essential to determine the timing of infection. Conjointly, a cell line constitutively expressing human-murine chimeric antibody with the variable regions of monoclonal antibody CVV-17 and constant regions of human IgM was developed to provide positive control material. The new cell line produced antibody with reactivity in the assay equivalent to that of a human serum sample positive for anti-CVV IgM. Five of seven archived human specimens diagnostically confirmed as CVV positive tested positive in the MAC-ELISA, whereas 44 specimens confirmed positive for another arboviral infection tested negative, showing good initial correlation of the CVV MAC-ELISA. Two of 27 previously collected serum samples from febrile patients in Yucatán, Mexico, who tested negative for a recent flaviviral or alphaviral infection were positive in both the MAC-ELISA and PRNT, indicating a possible recent infection with CVV or related orthobunyavirus. The MAC-ELISA described here will aid in making diagnostics more widely available for CVV in public health laboratories.
卡奇谷病毒（CVV）是一种由蚊子传播的正布尼亚病毒，在北美可引起反刍动物的流行病，其特征为先天性畸形和胎儿死亡。目前仅确认了7例人类感染病例；关于其作为人类致畸原的潜力，现有信息有限。CVV感染的诊断依赖于蚀斑减少中和试验（PRNT），该试验需要活病毒，耗时较长，且无法区分近期感染和既往感染。为了改进CVV的诊断方法，我们开发了一种IgM抗体捕获酶联免疫吸附测定法（MAC-ELISA），用于检测诊断标本中的抗CVV人类IgM，该方法比PRNT执行速度更快，且对IgM具有特异性，这对于确定感染时间至关重要。同时，构建了一种组成型表达人鼠嵌合抗体的细胞系，其具有单克隆抗体CVV-17的可变区和人IgM的恒定区，用于提供阳性对照材料。新细胞系产生的抗体在检测中的反应性与人血清样本中抗CVV IgM阳性的反应性相当。7份经诊断确认为CVV阳性的存档人类标本中有5份在MAC-ELISA检测中呈阳性，而44份经确认另一种虫媒病毒感染阳性的标本检测为阴性，表明CVV MAC-ELISA具有良好的初步相关性。在墨西哥尤卡坦半岛，从近期黄病毒或甲病毒感染检测为阴性的发热患者中收集的27份先前血清样本中，有2份在MAC-ELISA和PRNT检测中均呈阳性，这表明可能近期感染了CVV或相关正布尼亚病毒。本文所述的MAC-ELISA将有助于在公共卫生实验室更广泛地开展CVV诊断。
