Laboratory and Epidemiology Communications Difference of Poliovirus Isolation from Stool Specimens in Different Cell Lines

During the examination of stool specimens from countries where wild polioviruses still exist, we noted discrepancies among different cell lines. Table I shows virus isolation from stool speclmenS COllected in Cambodia during 1 996-97; three cell lines, RD, HEp-2, and Lα cells are.included (2)･ There were some differences in the poliovirus ISOlation results.As for the isolation of wild polioviruses, the number of isolates was 21, 25,and 23 in HEp-2, RD,and Lα cells, respectively. There were also some differences inthe number of vaccinestrain isolates among examinations of different cell lines, as shown in Table I (the total number of isolates was 13 in the case ofHEp-2 cells, 12 in RD cells, and 14 in Lα cells)･ Tb investigate the reason for this discrepancy, we measured poliovirus titers in stool extracts. Seven stool speclmensPOSitive for typel wild poliovirus were selected. Of the seven speclmenS, three were positive for wild poliovirus in all three cell lines; however, the other four speclmensWere negative as shown in Table 2. CamlO8, one of our specimen codes (Cam: Specimen from Cambodia; 108: the serial number in our laboratory), was negative for wild poliovirus in HEp-2 and La cells, but