Hydroxyapatite-coated nylon beads as a new reagent to develop a particle agglutination assay system for detecting Japanese encephalitis virus-specific human antibodies.

BACKGROUND

Detection of Japanese encephalitis virus (JEV)-specific antibodies is done today by hemagglutination-inhibition assay (HIA), neutralization assay (NTA) and enzyme-linked immunosorbent assay (ELISA). These conventional assays are often difficult to perform in diagnostic laboratories with insufficient resources. An alternative antibody detection kit, which is simple, preservable and inexpensive, is needed for extended use in rural areas of Asia.

OBJECTIVES

(i) Characterization of a new antigen carrier, hydroxyapatite-coated nylon (Ha-Ny) beads, and (ii) evaluation of the JEV antigen-coated Ha-Ny beads as a reagent to detect anti-JEV antibodies in human serum samples.

STUDY DESIGN

We examined the Ha-Ny beads for hydroxyapatite content, precipitation efficiency and protein adsorption ability. We then developed a particle agglutination assay system using the JEV antigen-coated Ha-Ny beads, and tried out the newly developed assay system with reference serum samples.

RESULTS

The beads had the ability to adsorb 0.44 mg of lysozyme per gram. Sedimentation speed was 10.2 cm/30 min in phosphate buffered saline (PBS), pH 7.0. Binding of the JEV antigen on Ha-Ny beads was confirmed by scanning electron microscopy (SEM) and ELISA. Eighteen confirmed-human serum samples were tested by the newly developed particle agglutination assay system. The results were consistent with those from HIA, NTA and ELISA.

CONCLUSION

The Ha-Ny beads can be applicable to the development of a new JEV antibody-detection kit, which does not require specific laboratory facilities.