4.4 Is Respiratory Administration of the Vector Associated Vith Damage to 
the Lung? 
From what is known about adenoviruses in general, it is possible that the 
vector will damage the respiratory epithelium (or other lung components). 
This might take place through: (1) direct injury mediated by structural 
components of the virus [e.g., by penton "injury" to the cells as occurs 
with high MO I in culture (Everett, 1958; Pereira, 1958; Petterson, 1984)]; 
(2) injury mediated by replication of the virus, expression of viral genes, 
or expression of the CFTR cDNA; and (3) injury mediated via the inflammato- 
ry/ immune system. 
To evaluate the possibility of damage by an E1“E3“ recombinant adenovirus 
vector (through whatever mechanism), a series of studies have been carried 
out in cotton rats and nonhuman primates. 
One time intratracheal administration of AvlCFl (10 9 pfu/kg) to cotton rats 
(experiment CRC.002) resulted in no deaths over a 10 day period of observa- 
tion (AvlCFl n=17 , vehicle n=15 , naive n=ll) . Animals were sacrificed at 
day 3 (AvlCFl n=6 , vehicle n=5 , naive n=5) , or at day 10 (AvlCFl n=3 , 
vehicle n=2 , naive n=5) . Morphologic assessment at day 3 showed the AvlCFl 
group had a patchy lymphocyte -dominated inflammatory reaction in the 
bronchoalveolar area. There was increased intensity at day 10, with in- 
flammation localized around the vasculature, and, to a lesser extent, the 
airways. There were no morphologic abnormalities observed in the cells of 
the airway or alveolar epithelium. The vehicle group showed a very mild 
inflammatory reaction at day 3 which disappeared by day 10. The naive 
animals showed no changes . 
A similar study with one time intra-nasal administration of AvlCFl (10 10 
pfu/kg) (experiment CRCW.003) demonstrated a similar pattern over a 7 day 
period of observation (AvlCFl n=26, vehicle n=22, naive n=12) . There was 
one death in the AvlCFl group (day 4) and one death in the vehicle group 
(day 5). The animals were sacrificed at day 3 (AvlCFl n=3 , vehicle n=3 , 
naive n=3) and day 7 (AvlCFl n=3 , vehicle n=2 , naive n=3) . Morphologic 
assessment was similar to the first group of animals (experiment CRC.002) 
with the exception that some of the AvlCFl infected animals also showed a 
very mild increase in the size of type II alveolar epithelial cells. 
In another study (CRC.008), single nasal administration of AvlCFl to cotton 
rats (4.3xl0 10 pfu/kg) is being compared to Ad5 (1.6xl0 10 pfu/kg). Animals 
will be evaluated at 1 hour and 3, 7, 14, and 28 days after infection and 
the two infected groups compared to naive animals in the same cages ("ca- 
nary" group) as well as to animals receiving vehicle alone. After 4 weeks, 
there were no deaths in the AvlCFl group (0/4 evaluated at 3 days, 0/4 
evaluated at 7 days, and 0/4 evaluated at 14 days, 0/4 evaluated at 28 
days). In contrast, there were 5/16 deaths in the Ad5 group. There were no 
deaths in the "canary" group (0/3 of the 3 day group, 0/3 of the 7 day 
group, 0/3 of the 14 day group, 0/3 of the 28 day group) or the vehicle 
group (0/2 of the 3 day group, 0/2 of the 7 day group, 0/2 of the 14 day 
group, 0/2 of the 28 day group). By 7 to 14 days, the animals receiving 
AvlCFl showed a mild to moderate inflammatory reaction in the airways and 
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Recombinant DNA Research, Volume 16 
