Serological detection of varicella-zoster virus-specific immunoglobulin G by an enzyme-linked immunosorbent assay using glycoprotein antigen

Abstract

Since the introduction of varicella vaccination in several countries, there has been an urgent need for commercially available test procedures that allow highly sensitive and specific quantitative determination of the varicella-zoster virus (VZV)-specific immune status, including immunity postimmunization. This study compared the performance of two enzyme-linked immunosorbent assays (ELISAs) for the sensitive and specific determination of VZV-specific immunoglobulin G (IgG) in seronegative and latently infected persons, as well as in vaccinees. One ELISA is based on the detection of antibody to VZV-specific envelope glycoproteins (gp), and the other comprises the whole antigen extract prepared from VZV-infected cells. A modified standard fluorescent-antibody-to-membrane-antigen (FAMA) assay was used as a reference. An excellent sensitivity (100%) in relation to FAMA was demonstrated for the gpELISA (Virion\Serion), while the non-gpELISA (Dade Behring) had a lower sensitivity (83%) when sera from latently infected persons were tested. After postvaccinal immunity was measured, a sensitivity of 87% was achieved with gpELISA, whereas the ELISA incorporating antigen extract of VZV-infected cells had a sensitivity of 78%. Excellent specificity (100%) was calculated for both the gpELISA and the non-gpELISA. In conclusion, SERION ELISA classic VZV IgG is useful for the sensitive and specific quantitative determination of VZV immune status after natural infection. The test can also be recommended for measuring antibody response after varicella vaccination, particularly after the cutoff value was optimized.