A reverse passive haemagglutination test for detection of Japanese encephalitis virus antigens in cerebrospinal fluid

A rapid sensitive and specific reverse passive haemagglutination test (RPHA) was developed for the detection of Japanese encephalitis virus (JEV) antigens in human cerebrospinal fluid (CSF). Sheep red cells were sensitized with five monoclonal antibodies (109, 112, 203, 204 and 301) reactive with envelope glycoprotein of JEV. Viral antigens were detected in CSF from 35 of 58 (60%) clinical cases of JE when the five MAb coated cells were used in combination. An IgM capture ELISA detected JEV specific antibodies in CSF among 52 of these 58 cases (90%). While 29 specimens contained both antigen and IgM antibodies, 23 had only IgM antibodies and 6 had only antigen. RPHA proved valuable for detection of viral antigens in CSF samples obtained within 10 days after onset of clinical symptoms. Amongst the five MAbs used, the individual antigen detection rates were 44, 12, 43, 12 and 36%, for MAbs 109, 112, 203, 204 and 301, respectively.