Transmissible gastroenteritis (TGE) of swine: survivor selection of TGE virus mutants in stomach juice of adult pigs.
Two transmissible gastroenteritis (TGE) virus mutants (188-SG and 152-SG) were obtained from a low-passage virus strain (D-52) by 188 and 152 cycles of stomach juice treatment and multiplication in cell culture. Compared to the high-passage Purdue-115 and the original D-52 strains, these mutants were more stable at pH 2.0, more resistant to pepsin and trypsin, and characterized by a small plaque phenotype. In vivo, the two mutants were not found to be virulent for 4-day-old piglets and sows after oral inoculation. To test induction of lactogenic immunity, the 188-SG mutant was administered orally to pregnant sows (6 or 7 weeks before parturition) followed by one intramuscular booster (1 week before parturition). After challenge with virulent TGE virus, piglet mortality 7 days after exposure was reduced (to 22%) as compared to the death rate in piglets from control sows (91%).
Aynaud
J M
JM
Nguyen
T D
TD
Bottreau
E
E
Brun
A
A
Vannier
P
P
D000818:Animals; D002460:Cell Line; D003332:Coronaviridae / Q000235:genetics*; D005750:Gastric Juice / Q000382:microbiology*; D005761:Gastroenteritis, Transmissible, of Swine / Q000635:transmission; D006863:Hydrogen-Ion Concentration; D007668:Kidney; D009154:Mutation; D012641:Selection, Genetic; D013045:Species Specificity; D013552:Swine; D005760:Transmissible gastroenteritis virus / Q000235:genetics* / Q000302:isolation & purification