Assay of arbovirus neutralizing antibody by micro methods

Abstract

Efficient, reproducible and specific neutralizing antibody assays are needed, particularly for use in arboviral studies in areas where antigenic cross reactions make serological interpretation difficult. Accordingly, 2 methods were developed for this purpose. A micrometabolic inhibition (MMI) test with BHK-21 cells in disposable “U”-bottomed microtitre plates was used with Japanese encephalitis, Wesselsbron, Sindbis, chikungunya and Batai viruses. The MMI test was highly specific, of efficiency comparable with the haemagglutination-inhibition (HI) test, and was very sparing of reagents and sera. Although equal to or better in sensitivity than conventional cell culture neutralization tests, it was not as sensitive as HI or plaque-reduction neutralization (PRN) tests. The LLC-MK2 cell microculture PRN test was devised for use with the dengue viruses or for use when a combination of precision of antibody measurement and efficiency of testing was required. The microculture and 1 oz. bottle culture PRN tests were of equal specificity. Although not as precise as the bottle PRN test, the microculture PRN test is suitable for routine serology and has the added advantages that it is more efficient and requires less serum and reagents.