Antibody assays for varicella-zoster virus: comparison of enzyme immunoassay with neutralization, immune adherence hemagglutination, and complement fixation

Serological reactivity of some monoclonal antibodies to varicella-zoster virus

Monoclonal antibodies to varicella-zoster virus, free from host cell reactivity, were produced by cell fusion technics. Antibodies from four different clones showed diverse activities in neutralization immunofluorescence and complement fixation assays. The antibodies provide useful reagents for viral diagnosis and viral antigenic characterization.

Enzyme-linked immunosorbent assay for detection of antibody to varicella-zoster virus

Primary varicella-zoster virus (VZV) infection is a serious illness in immunocompromised individuals, and a rapid, sensitive, and reliable assay to identify high-risk VZV-susceptible patients would be clinically useful. An enzyme-linked immunosorbent assay (ELISA) for antibody to VZV was compared with the fluorescent antibody-to-membrane antigen (FAMA) assay and found to be similar in both sensitivity and specificity. The antibody titers determined by both assays were also similar. The absence of antibody detected by ELISA correlated with susceptibility to VZV infection. Because it is simple to perform and has equivalent sensitivity to FAMA, ELISA should be useful for VZV antibody testing in diagnostic and research laboratories.

Visual reading of enzyme immunofluorescence assays for human cytomegalovirus antibodies

Enzyme immunofluorescence assays for cytomegalovirus antibodies could be read satisfactorily using a light box with ultraviolet illumination. Higher antibody titers were obtained with a fluorogenic substrate than with a color-producing substrate.

Immunoglobulins M and G to varicella-zoster virus measured by solid-phase radioimmunoassay: antibody responses to varicella and herpes zoster infections

Both immunoglobulin M (IgM) and IgG antibodies to varicella-zoster virus (VZV) were detectable in a solid-phase radioimmunoassay with 125I-labeled goat antisera to human immunoglobulins. Primary infection with VZV was associated with early production of IgM and IgG antibodies and rapid development of lymphocyte transformation to VZV antigen. Among eight subjects with varicella tested 1 to 4 days after onset, seven patients had IgG and six patients had IgM antibodies; all patients had both IgG and IgM antibodies within 7 days. An IgM response was documented by radioimmunoassay in 18 of 26 patients with herpes zoster. VZV antibodies could be assayed by radioimmunoassay in unfractionated serum with commercial goat antisera to human immunoglobulins and commercial VZV antigen. VZV-specific IgG binding was present in all sera from 42 subjects with a VZB antibody titer of greater than or equal to 1:8 as determined by indirect immunofluorescence and cellular immunity to VZV as determined by lymphocyte transformation and who had had varicella at least 20 years before testing. The geometric mean titer was 1:6,309, and titers were greater than or equal to 1:16,384 in 20 subjects. Antibody was present as determined by radioimmunoassay in 14 samples negative by complement fixation and in five samples negative by complement fixation and immune adherence hemagglutination. No specific binding was observed in 21 sera from subjects who were not immune to VZV as determined by indirect immunofluorescence or lymphocyte transformation despite the presence of herpes simplex or cytomegalovirus antibody indicated by complement fixation in 15 sera. High titers of VZV IgM antibody were detected in unfractionated sera despite the presence of high titers of VZV IgG antibody. The VZV radioimmunoassay provided a sensitive and practical method for measuring VZV IgG and IgM antibodies.

Enzyme immunoassay for measurement of antibodies to herpes simplex virus infection: comparison with complement fixation, immunofluorescent-antibody, and neutralization techniques

An enzyme immunoassay (EIA) was developed for detecting antibody to herpes simplex virus, and the results were compared with those of complement fixation, indirect immunofluorescent-antibody, and plaque reduction neutralization tests. Test sera showed very little nonspecific reactivity even at a starting dilution as low as 1:10. EIA results showed excellent correlation with results obtained by the neutralization test, with an average gain in sensitivity of 1.65. EIA proved very useful in detecting current herpes simplex virus infection, and antibody appeared in all cases soon after clinical onset. EIA appears to be a rapid, sensitive, and specific method for routine demonstration of herpes simplex virus antibody in a clinical setting.

Enzyme linked immunoassay and fluorescent antibody techniques in the diagnosis of viral diseases using staphylococcal protein—A instead of anti-gamma-globulins

Staphylococcal protein-A (SpA) is known to interact with the crystallizable fragment (Fc) of IgG molecules from several species. In the present study, SpA coupled to either fluorescein isothiocyanate (FITC) or peroxidase was used in place of antisera to IgG for the fluorescent antibody (FA) techniques and the enzyme linked immunoassay (ELISA). The SpA conjugates produced low background staining when applied in these techniques, and provide a rapid, highly specific and sensitive means for the identification of viral isolates and the detection of serum antibodies. Moreover, SpA is a single reagent that replaces various preparations of anti-gamma globulin against many species. SpA-FITC conjugate was successfully applied for the identification of pseudorabies virus, hog cholera virus, swine vesicular disease virus, transmissible gastroenteritis virus, porcine parvovirus and porcine enteroviruses. Antibody titers against the mentioned viruses could be determined semi-quantitatively in the indirect FA test with SpA-FITC. In our laboratory the ELISA became a routinely practicable serological test for the detection of antibodies only after we introduced SpA-peroxidase as a marker for the IgG.

Determination of IgA antibodies to human cytomegalovirus by enzyme-linked immunosorbent assay (ELISA)

A sensitive enzyme-linked immunosorbent assay (ELISA) is described for detection of IgA antibodies cytomegalovirus (CMV). The antigen consisted of a sonicated extract of CMV infected human embryo cells. The tested sera were absorbed with staphylococcus aureus (strain Cowan 1) before analysis. Rabbit antihuman IgA peroxidase conjugate was used to detect human IgA bound to viral antigen. In parallel, Igm and IgG antibodies to CMV were studied by ELISA and by the immunoperoxidase antibody to membrane antigen (IPAMA) technique, respectively. CMV IgA was detected in high titers by ELISA in eight of nine CMV patients. The maximal IgA titers were generally lower than the IgM titers detected by ELISA. No CMV IgA antibodies (titer less than 20) were detected by ELISA in 57 control sera (healthy adults, hospitalized patients with various other diseases), paired sera of five patients with acute herpes simplex, infection, two patients with Epstein-Barr infections, one patients with varicella, and one with zoster infections. The potential application of the ELISA CMV IgA technique in serodiagnosis of CMV infections is discussed.

Antigen requirements, sensitivity, and specificity of enzyme immunoassays for measles and rubella viral antibodies

Enzyme immunoassay (EIA) systems for measles virus and rubella virus were studied from the standpoints of requirements for suitable viral antigens and control antigens, and the sensitivity and specificity of the tests for detecting antibody elicited by past infection (determination of immunity status), and for serodiagnosis of currenet infections. Crude or semipurified measles virus antigens were satisfactory for EIA, but antigens derived by pelleting virus from infected cell culture fluids were slightly more specific in their reactivity than were antigens produced from lysates of infected cells. However, reliable rubella EIA antigens could be produced only from infected cell culture fluids, and they required density gradient purification to render them suitably specific. Even with gradient-purified rubella antigens, it was necessary to use antigen prepared in an identical fashion from uninfected cell culture fluids as a control on the specificity of reactions obtained with test sera. With appropriate viral antigens and control antigens, both measles and rubella EIA systems were highly sensitive and specific for determination of immunity status and for serodiagnosis of current infections. Antibody was detectable earlier in the course of infection by EIA than by hemagglutination inhibition or complement fixation, but this did not limit the diagnostic value of the test, since titer increases demonstrable by EIA were usually greater than those detectable by hemagglutination inhibition or complement fixation tests.