[Laboratory procedures in adenoviruses. II. Sensitivity of various cell cultures as determined by endpoint titration...

The sensitivity of human embryonic kidney (HEK), human amnion (HAm) and HeLa cells for human adenoviruses was investigated by means of endpoint titrations of 13 prototype strains and numerous original specimens from patients. Prototypes and original specimens showed the same behavior. Adenoviruses of subgrouppp III produced nearly identical titers in all 3 cell cultures, while for subgroup I HAm cells showed a 10- to 100-fold lower titer. On the other hand, HAm cells are nearly as sensitive as HEK cells for type 8, whereas HeLa cells are less sensitive. For other viruses of subgroup II and for subgrou IV, HAm (for type 12 also HeLa) cells are less sensitive than HEK cells. Out of three HeLa cell strains tested the Bristol strain was inferior to the other two in its sensitivity. Concerning the speed of the CPE development, HEK cells are superior for all types, the difference being greatest for subgroup I towards HAm and HeLa and for type 8 towards HeLa cells. The length of incubation necessary for the appearance of CPE even with minimal amounts of virus is 40 days for type 8 in all kinds of cell cultures, whereas for adenoviruses of sub-groups I and III, which are predominantly isolated in the routine laboratory, 25 days for HEK and 30 days for HAm and HeLa cells may suffice in most cases. When endpoint titrations are compared with titers obtained by immunofluorescence, it appears that this technique may be applied as a screening method; thus long incubation periods of negative specimens can be saved. The amounts of infectious virus present in original specimens are reported; the highest quantity was found in specimens containing subgroup I viruses.