Figure 2. 5 -A. Assessment of a preparation of an El~, replication deficient 
Ad5 -based adenovirus for contamination with Ad5 . The example shown is for 
the vector AvlCFl . Mixtures of Ad5 (WT) and AvlCFl from 1:1 to 1:10 -5 were 
evaluated by amplification with Ela specific primers followed by southern 
analysis using a 32 P-nested Ela probe. No Ela sequences are present in the 
H 2 0 control (lane 1) or AvlCFl alone (lane 2). Ela sequences are readily 
detectable in a mixture 1 of Ad5 and AvlCFl to at least a ratio of 1:10 -5 
(lanes 3-8). At the exposure shown the signal at 10 -5 (lane 8) is not seen; 
with longer exposures (not shown) a clear signal at 10 -5 is observed. The 
expected Ela fragment is 337 bp. See text (section 2.5) for further de- 
tails . 
Wild type 
Ad5 ^ f 
Recombinant 
AvlCFl 
AvlCFl 
alone 
WT/ AvlCFl 
1 1(T 2 KT* 
bp 
Amplification with 
Ela-specific 
primers 
Evaluate 
© Presence of Ela DNA by 
Southern analysis 
( 32 P-nested Ela probe) 
1 2 3 4 5 6 7 8 
Recombinant DNA Research, Volume 16 
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