Effect of Trypsin on Viral Susceptibility of Vero Cell Cultures-Cercopithecus Kidney Line

Serial Passages of Parainfluenza Type 1 (Ha-2) Virus in the Continuous Cell Lines From Porcine, Rabbit and Green Monkey Kidneys Using the Trypsin-Added Systems

“…Identity of the strain was confirmed repeatedly (Itoh et al, 1968;Morimoto et al, 1970;Okawa et al, 1970). Cell lines GMK-2 (from Dr. M. Nakano of the National Institute of Health, Tokyo), PS (from Dr. Y. Inoue of Kyoto University) and RK-13 (from Dr. Y. Akao of the National Institute of Health, Tokyo) were used after many passages in our laboratory.…”

“…The addition of a small quantity of trypsin to the maintenance medium of Vero cell cultures converted incomplete reproduction cycles of certain parainfluenza and influenza viruses to complete cycles (Morimoto, Doi and Itoh, 1970 ;Okawa et al, 1970;Itoh et al, 1970). It was considered by us that viral susceptibility of Vero cell cultures may have been widened, so they can be used for cultivation, antigen preparation, inf ectivity titration and serological procedures of more kinds of viruses.…”

“…All cell lines were maintained in serum-free medium 199 containing sodiumm bicarbonate in 0.11 % for the former two and in 0.05 % for RK-13. For the trypsinadded cell culture system (t-system), the technique employed for Vero cell cultures (Morimoto et al, 1970) was followed.…”

“…The final concentration of trypsin in the maintenance medium was 1.5-1.8 ,cog/ml and incubation of the inoculated tube cultures was made in the stationary rack at 33-36 C. Titration of virus inf ectivity was made by our routine method (Itoh et al, 1970) using tube cultures. Calculation of TCD5a was based on the results of hemadsorption tests using guinea pig erythrocytes performed during the 5th to the 7th day after inoculation.…”

Physical and chemical methods for enhancing rapid detection of viruses and other agents

“…Heat shock enhanced HIV type 1 replication in peripheral blood lymphocyte cultures (76,232 (28,74,122,131,145,154,155,185,201,249,262,278 (6) found that yields of bovine rotavirus were increased up to 3 log1o when trypsin was incorporated into cell culture medium. The proteolytic enzymes trypsin and elastase have been shown to enhance the growth of simian, porcine, and bovine rotaviruses (105).…”