Study on adaptation of hepatitis A virus strain HM-175 to primary monkey kidney cell culture for preparation of an inactivated hepatitis A vaccine

ABSTRACT

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 50% of cells were infected. Hepatitis A viruses replicated 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 cells associated viruses. 10 days after inoculation was the best time to have high titer. A serial passage of HAV HM-175 on primary cell culture of monkey kidney was not successful in getting higher titer and shorter time of inoculation, so it was not necessary to conduct serial passages. The optimal infectious dose was determinated as 0.03 pfu/cell