LIVE POLIO IRUS VACCINES

102 Safety-Laboratory Evidence of Attenuation and Safety
TABLE 1. SELECTIVE ENRICHMENT OF 25 ° C. VARIANT BY SERIAL PROPAGATION AT PROGRESSIVELY
LOWER TEMPERATURES
Type 1 Poliovirus-Strain LSc,
2ab
CPE TITER (LOG 10 TCD 0/ML ) AT INDICATED TEMPERAIURE
EMPERATURE
PASSAGE 36 0 C 30 0 C 25°C
OF NO. 8 DAYS 14 DAYS
NO. 8 DAYS 8 DAYS L -
PROPAGATION COMPLETE PARTIAL COMPLETE PARTIAL
36 ° VACCINE + 1 8.2 8.2 0 0 0 2. Z light
330 7 8.2 0 1.Z 3.0 3.7
30 ° 5 8.1 7.9 0 1.4 5.0 5.3
10 7.7 7.3 0 4.1 5.4 5.7
250 5 6. Z 3.2 4.2 6.2 6.Z
10 7.4 4.2 6.4 7.7 7,7
20 7.3 5.Z2 7:3 7.7 7.7
Selective Enrichment of 25 0 C Variant by Serial Propagation at Progressively Lower Temperatures
Type 1 Attenuated Polioviruses
LSc , 2ab
36 36 2 362
25
V- I P 5 p 10 ,P 5 P IO P 20
36 o 30) 25"
P 2149
36 30
P2226
36° 30036 25
3s
25
25°
jCPE titer ct 36°C al 8doys, -ParliaI CPE titeral 25Co 14 doys
-_Complete " " " " "
FIG. 1