Nguyen Thu Van, Hoang Thuy Nguyen, Hoang Quynh Tran, Nguyen Tuyet Nga
National
The hepatitis A virus strain HM-175 was adapted to primary monkey kidney cell culture Maccaca mulatta for the study of development of an inactivated purified hepatitis A vaccine derived from cell culture. Using immuno-fluorescent method, it was detected that the hepatitis A viruses replicated very well inside cytoplasma and induced a typical cytophatic effect. After 10 days of inoculation, about 10% of cells were infected. Hepatitis A viruses replicate very slowly. This study found that the time for complet inducing CPE was 21 days and titers of released viruses and cell associated viruses are similar, therefore the procedure for preparation of hepatitis A vaccine should include the step of cell sonication for separation of all cell associated viruses. 10 days after inoculation was the best time to have high titer. A serial passages of HAV HM-175 on primary monkey kidney cell culture was not successfull in getting higher titer and shoter time of inoculation, so it was not neccesary to conduct a serial passages. The optimmal infectious dose was determinated as 0.03 pfu/cell.