Antibodies to dengue viral polypeptides. I. Sensitivity and specificity of the viral-antigen-strips/enzymeimmunoassay (VAS/EIA).

ABSTRACT

The authors applied polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE), western blot, and enzymeimmunoassay (EIA) for the detection of antibodies toward individual dengue viral proteins or polypeptides. SDS-PAGE procedure as described by Laemmli et al., was applied and modified. The results can be observed by visualization. The scores, from 0 to 4, can be assigned by comparing the intensity of the color development. Besides being sensitive and rapid, this technique yields information of the polypeptides or molecular level. An increasing of intensities of positive reactions indicated rising in antibodies titers and all serotypes of dengue viruses (from type 1 to type 4) can be tested together allowing reliable comparison among serotypes. With hyperimmune human sera, at least 13 polypeptides reacted with sera while negative non-immune subject showed no reaction. It is highly possible to use this technique as a rapid quantitative and for qualitative analysis of antibodies to individual viral proteins as well.