Establishment and application of micro-neutralization test to determine neutralizing antibody against ZIKA virus in sera

Objective To develop a micro-neutralization test for determination of neutralizing antibody against ZIKA virus (ZIKV) in human sera and to verify the acute and convalescent serum samples of 10 ZIKA virus-infected cases diagnosed by nucleic acid detection and/or virus isolation. Methods ZIKV isolated from ZIKA cases was used to determine micro-neutralization antibody. The virus solution was prepared by infecting BHK21, VERO and VERO-E6 cell lines and viral titer was tested; 100 TCID50 viral solution and 4 times diluted sera which were inactivated at 56 ℃ for 30 min were neutralized, then added the cell suspension and incubated in 5% CO2 incubator at 37 ℃ for 7 d. The CPE was observed every day. Results The sensitivity of BHK21, VERO and VERO-E6 was different after infection with ZIKA virus. VERO cell line was the most sensitive and showed typical CPE. VERO cell line was used to establish a micro-neutralization test for determination of neutralizing antibody against ZIKA virus in sera. Conclusions The neutralizing antibody test for zika virus in sera is a special and usefulmethod to diagnose human infection of ZIKV and to conduct population based epidemiological investigation. Key words: Neutralizing antibody; ZIKA virus; VERO cell line