Objective—To determine whether infectious retrovirus
was inactivated in bones from FeLV-infected cats after
ethylene oxide (ETO) sterilization or preservation in a
98% solution of glycerol in an in vitro cell culture system.
Sample Population—Metatarsal bones obtained
from 5 FeLV-infected cats and cultured with feline
Procedure—Metatarsal bones were treated with
100% ETO, a 98% solution of glycerol, or left untreated.
Twenty-five flasks of feline fibroblast cells were
assigned to 5 groups: negative control, positive control,
ETO-treated bone, glycerol-treated bone, and
untreated bone with 5 replicates/group for 4 passages.
Media and cell samples were harvested from
every flask at each passage to measure FeLV p27 antigen
and the number of copies of provirus per 100 ng
of DNA, respectively.
Results—All negative control and ETO-treated group
replicates were negative for FeLV p27 antigen and
provirus throughout the study. All positive control
group replicates were positive for FeLV p27 antigen
and provirus at passages 1 to 4. Untreated bone group
replicates were positive for FeLV p27 antigen at passages
3 and 4 and provirus beginning at passage 2.
Glycerol-treated group replicates had delayed cell replication
and were negative for FeLV p27 antigen and
provirus at passages 1 to 4 and 2 to 4, respectively.
Conclusions and Clinical Relevance—Ethylene
oxide sterilization of bone from FeLV-infected cats
appeared to abrogate transmission of infectious retrovirus
and effectively sterilized bone allografts.
Impact for Human Medicine—Additional studies to
confirm effectiveness of ETO treatment of allograft
tissues for prevention of pathogen transmission via
transplantation are warranted. (Am J Vet Res
Objectives—To compare virucidal effects and bone
incorporation properties of cortical bone allografts transplanted
into specific-pathogen-free (SPF) cats.
Allografts consisted of untreated bone from a SPF cat
(negative-control group) and bone from 5 FeLV-infected
cats that was subjected to sterilization with ethylene
oxide (ETO), preservation with glycerol, or no treatment
Sample Population—Bones from the aforementioned
groups and twenty 8-week-old SPF cats (5
cats/group) implanted with an allograft from 1 of the
Procedure—After implantation, blood samples were
collected weekly to monitor FeLV p27 antigen and antibody
titers. Quantification of FeLV provirus was performed
on blood samples at weeks 0, 4, and 8 and
donor bone samples at time of implantation. Cats were
euthanatized 8 weeks after transplantation, and graft
sites were evaluated.
Results—All results for negative-control cats were negative.
All ETO group cats had negative results for antigen
and provirus in blood, whereas 1 cat had a low antibody
titer. Although 3 ETO-treated allografts were positive for
provirus, the DNA appeared denatured. One cat in the
glycerol group had positive results for all tests in blood
samples. All glycerol-preserved allografts were positive
when tested for provirus. All results for positive-control
group cats were positive. Differences in incorporation of
bone grafts were not observed.
Conclusions and Clinical Relevance—Glycerol
preservation of FeLV-infected bone allografts did not
eliminate transmission of retrovirus to recipients. In
contrast, ETO sterilization appeared to denature DNA
and prevent infection. Treatments did not affect incorporation
of bone grafts in young cats. (Am J Vet Res 2000;61:665–671)