In vitro differentiation and pH sensitivity of field and cell culture-attentuated strains of transmissible gastroenteritis virus

Abstract

Characteristics of four transmissible gastroenteritis (TGE) virus field strains (Miller, Purdue, Bl, and V203) and four cell culture-attenuated strains (Purdue, SH, CKp, and Bl) were studied to find methods of differentiation between the two groups of viruses. TGE field virus strains did not replicate as well as attenuated strains at 37 C and could not be passaged serially for more than four to six passages at 33 C. There were clear differences in plaque size when the strains were compared. Field strains had average plaque sizes ranging from 3.59 to 3.15 mm, whereas attenuated strains induced plaques that were larger than 4.2 mm. Variations were observed in stability of strains at pH 3.0. Field strains and cell culture-attenuated strains CKp-270 and SH-114 were reduced in titer by about 1 log10. A reduction of about 3 log1o, however, was obtained with cell culture strains B1-300 and Purdue-113.

Monoclonal antibodies to a virulent strain of transmissible gastroenteritis virus: comparison of reactivity with virulent and attenuated virus

“…Biochemical and biophysical differences among field isolates and cell cultureattenuated TGEV have been reported [4,7], but serologic differences were not identified [13,14]. Using MAbs to Purdue TGEV in competitive assays, Delmas et al [3] demonstrated that the neutralization mediating determinants were highly conserved among TGEV strains.…”

Physico-chemical properties of murine hepatitis virus, strain A59

“…However, this virus showed marked instability at pH above its optimum pH of 6.5, when incubated for 24 hours (21). Similar to IBV, TGEV strains showed great variability in their stabilities to an acidic environment (12). Moreover, TGEV strains were generally heat-labile since they were inactivated in a few days at 37°C and in 10 minutes at 56°C (3,15,18).…”

Étude comparée de trois souches du coronavirus de la gastroentérite transmissible: Conditions de la réplicationvirale et de la synthèse des antigènes structuraux

“…La gastroenterite transmissible (GET) est une enterite neonatale mortelle, hautement contagieuse, causee par un coronavirus specifique de l'espece porcine; Ia GET est responsable de lourdes pertes economiques en production porcine. La relation entre Ie pouvoir pathogene du virus et d'eventuels marqueurs in vitro lies par exemple aux conditions de sa replication, fait encore l'objet de controverse [9,11,14,17]. Apres un certain nombre de passages en serie sur culture cellulaire, le virus OET perd une grande partie de son pouvoir pathogene.…”

“…Au-dela de cette dose (7 ug/ml) le metaperiodate affecte I'antigenicite non seulement de deux glycoproteines (E1 et E2) mais aussi de la nucleoproteine (NP) qui n'est pas glycosylee (fig. 7).DISCUSSIONLa thermosensibilite de la replication a ete proposee dans le passe comme marqueur de la virulence du virus de la OET[9,11]. Pourtant, recemment, a partir de huit souches du virus, Laude et coll [14].…”