Summary auto-generated
This study describes a novel assay for detecting antiviral antibodies based on antibody-dependent plaque enhancement (ADPE) in P388D1 macrophage cells. When specific antiviral antibodies are present at low concentrations, they enhance virus replication in these cells up to 100-fold, an effect dependent on the Fc receptor. The authors tested this assay against multiple virus families and compared its sensitivity to established methods including hemagglutination inhibition, plaque reduction neutralization tests, and solid-phase radioimmune assay. The ADPE assay proved as sensitive or more sensitive than radioimmune assay and approximately 100 times more sensitive than traditional neutralization methods. The assay worked effectively for flaviviruses, alphaviruses, and Bunyaviridae tested, but failed for Herpesviridae and Picornaviridae. Variables affecting the assay, including cell density, antibody preincubation time, and antibody concentration, were systematically investigated. A prozone effect occurred at high antibody concentrations due to virus neutralization. The authors conclude that ADPE provides a simple, reproducible, and sensitive method for antiviral antibody detection with potential applications in epidemiology and serodiagnosis.
Key findings
- ADPE in macrophage P388D1 cells is as sensitive or more sensitive than radioimmune assay for detecting antiviral antibodies and 100-fold more sensitive than hemagglutination inhibition or plaque reduction neutralization tests
- The enhancement effect is Fc receptor-dependent and works effectively for flaviviruses, alphaviruses, and Bunyaviridae but not for Herpesviridae or Picornaviridae
- Optimal assay performance requires careful control of cell density, minimal virus-antibody preincubation time, and recognition of a prozone effect at high antibody concentrations
- Cross-reactive antibodies from antigenically related viruses can enhance plaque formation, though with lower titers than homologous antibodies
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Abstract
An assay for antiviral antibody based on antibody-dependent plaque enhancement (ADPE) in the macrophage cell line P388D1 is described which is as sensitive as, or more sensitive than a radioimmune assay. The method is applicable to a range of Togaviridae and Bunyaviridae although not to Picornaviridae and Herpesviridae. The variables affecting the assay are investigated.