Tobler L H, Stramer S L, Chien D Y, Lin S, Arcangel P, Phelps B H, Cooper S L, Busch M P
Blood Systems Research Institute, San Francisco, CA, USA.
Vox Sang. 2007 Jan;92(1):1-7. doi: 10.1111/j.1423-0410.2006.00856.x.
Conformational viral proteins potentially play an important role in the immunobiology of acute hepatitis C virus (HCV) infection and may enable earlier antibody detection.
HCV RNA was detected using nucleic acid testing. Early antibody production was evaluated using three enzyme immunoassays (EIAs) containing antigenic proteins not present in licensed EIAs. Respectively, these contained: (1) multiple-epitope fusion antigen (MEFA) 7.1-NS3/4a, (2) F and Core, and (3) E1/E2 proteins. NS3/4a is a conformational antigen retaining protease and helicase enzymatic activities. MEFA 7.1 contains the linear epitopes used in licenced EIAs, including the latest EIA-3.0, in combination with genotype 1-3 specific epitopes. Forty-two RNA positive, EIA-3.0 negative samples, including two persistently serosilent cases, were used to evaluate these research EIAs. As controls, 54 EIA-3.0 negative/RNA negative and three HCV RNA+/antibody positive specimens were included.
Only the MEFA 7.1-NS3/4a EIA was positive in seven (17%) of the 42 HCV RNA + specimens, in all three EIA-3.0 positive controls but in none of 54 EIA-3.0 negative/HCV RNA negative controls. Notably, six of the seven (86%) specimens had evidence of active hepatitis (ALT > 210 IU/l). The two serosilent cases were research EIA negative.
A novel EIA with conformational and linear epitopes detected HCV antibodies in 17% of viraemic specimens missed by the standard reference EIA-3.0. Our research EIA appears to detect HCV antibodies closer to the initiation of acute hepatitis. Given that the average RNA-positive, antibody-negative window period is 56.4 days, this 17% yield would translate into a 10-day earlier detection of antibodies.
构象性病毒蛋白可能在急性丙型肝炎病毒（HCV）感染的免疫生物学中发挥重要作用，并可能有助于更早地检测到抗体。
使用核酸检测法检测HCV RNA。采用三种酶免疫测定法（EIA）评估早期抗体产生情况，这三种EIA含有已获许可的EIA中不存在的抗原蛋白。具体而言，它们分别包含：（1）多表位融合抗原（MEFA）7.1-NS3/4a，（2）F和核心蛋白，以及（3）E1/E2蛋白。NS3/4a是一种保留蛋白酶和解旋酶酶活性的构象性抗原。MEFA 7.1包含已获许可的EIA（包括最新的EIA-3.0）中使用的线性表位，以及1-3基因型特异性表位。42份RNA阳性、EIA-3.0阴性样本（包括2例持续血清学阴性病例）用于评估这些研究性EIA。作为对照，纳入了54份EIA-3.0阴性/RNA阴性样本和3份HCV RNA阳性/抗体阳性标本。
在42份HCV RNA阳性标本中，只有MEFA 7.1-NS3/4a EIA在7份（17%）标本中呈阳性，在所有3份EIA-3.0阳性对照中呈阳性，但在54份EIA-3.0阴性/HCV RNA阴性对照中均为阴性。值得注意的是，7份标本中有6份（86%）有活动性肝炎的证据（ALT>210 IU/l）。2例血清学阴性病例的研究性EIA结果为阴性。
一种具有构象性和线性表位的新型EIA在17%的病毒血症标本中检测到了HCV抗体，而这些标本被标准参考EIA-3.0遗漏。我们的研究性EIA似乎能在更接近急性肝炎发病时检测到HCV抗体。鉴于RNA阳性、抗体阴性的平均窗口期为56.4天，这17%的检出率意味着抗体检测可提前10天。
