STUDIES ON THE EFFICIENCY OF MEASLES-VIRUS ANTIGEN PRODUCTION USING VERO CELL-CULTURE IN A MICROCARRIER SYSTEM

1. A large amount of antigen is required to conduct seroepidemiologic surveys of measles. Thus, a process to obtain measles virus antigen us ing a bioreactor was standardized. 2. The virus was grown in a 3.7-l c ulture of VERO cells using a Celligen cell culture system containing 2 mg/ml of microcarriers (cytodex I) at 37-degrees-C and 60 rpm. The cu ltures infected with 0.5 m.o.i. of measles virus were harvested after the appearance of the cytopathic effect. The virus suspension was clar ified and concentrated by ultracentrifugation. Intracellular and extra cellular virus titers were determined by hemagglutination (HA) and by induction of a cytopathic effect in cell culture (TCID50). 3. Intracel lular virus presented 5-7 x 10(6) TCID50/0.1 ml, HA activity per 50 mu l equal to 32, with a total HA activity of 4,480 HA units (HAU) and sp ecific activity of 116 HAU/mg. In the concentrated supernatants, the H A titer of extracellular virus was 64, with a total HA activity of 1,0 24 HAU and a specific activity of 1,600 HAU/mg. 4. The antigen obtaine d was suitable for the detection of antibodies against measles virus i n assays such as ELISA and DOT-ELISA (using 1 mug/well to ELISA and 2 mug/DOT). 5. The microcarrier system produced antigen sufficient for 2 6 ELISAs/ml compared to 5.7 ELISAs/ml obtained for the static culture system.