Y. Gao et al., TRUNCATED BOVINE HERPESVIRUS-1 GLYCOPROTEIN I (GPI) INITIATES A PROTECTIVE LOCAL IMMUNE-RESPONSE IN ITS NATURAL HOST, Vaccine, 12(2), 1994, pp. 145-152
Current modified live and killed BHV-1 vaccines have not reduced the i
ncidence of bovine herpesvirus-1 (BHV-1), the principal viral agent in
bovine respiratory disease complex. The requirement for production of
viral proteins for immune study has resulted in the establishment of
a cell line which constitutively expresses BHV-1 gpI. A truncated BHV-
1 envelope gpI protein was secreted into the culture supernatant of D1
7 cells transfected with the gpI gene lacking the coding sequence for
the transmembrane region (TMR). The transmembrane domain is essential
for gpl stability in the envelope, virus infectivity and, most probabl
y, natural killer cell recognition; however, we have tested the possib
ility that this domain is not required for inducing an adaptive, prote
ctive immune response. Immunization of calves with this truncated gpl
protein induced gpI-specific nasal IgA, IgG1, serum neutralizing antib
odies and gpI-specific peripheral lymphocyte proliferation. All immuni
zed calves were protected from clinical disease after BHV-1 challenge.
Further, nine of ten immunized calves had no intranasal viral sheddin
g. One animal shed a minimal amount of virus following challenge, but
produced no antibodies to other viral proteins as evidenced by immunop
recipitation of S-35-labelled viral proteins by sera from virus-challe
nged animals. This study represents the first evidence that a recombin
ant truncated gpI subunit vaccine can confer local mucosal immunity an
d establish a strong protective barrier against disease caused by BHV-
1 in the natural host. Also, these data demonstrate the feasibility of
preventing initial viral replication in the host and distinguishing v
accinated from wild-type virus-infected animals.