Abstract
The YP11mu strain of a plaque-selected canine herpesvirus (CHV) encoded a smaller molecular weight (MW) of gD than those of other strains including YP2 strain (Xuan et al., 1990). When nucleotide sequence of the mutated gD of YP11mu strain (gD(YP11mu)) was compared with that of gDs of other CHV strains, gD(YP11mu) lacked 12 nucleotides encoding 4 amino acids, NKTI, including one predicted potential N-linked glycosylation site and no other change was found in other regions. When the gD(YP11mu) and gD of YP2 strain (gD(YP2)) expressed in COS-7 and insect (Spodoptera frugiperda; Sf9) cells were compared each other, both gDs reacted with a panel of monoclonal antibodies (MAbs) against CHV gD by indirect immunofluorescence analysis and the gD(YP11mu) possessed an MW of approximately 47-51 and 39-44 kDa in COS-7 and Sf9 cells, respectively, which were smaller than the expressed gD(YP2) (approximately 51-55 and 41-46 kDa, respectively) by immunoblot analysis. After treatment with tunicamycin, the MW of both gDs in Sf9 cells became approximately 37 kDa. When hemagglutination (HA) test using canine red blood cells (RBC) were carried out, lysates of Sf9 cells expressing CHV gDs agglutinated canine RBC. Serum from mice inoculated with lysates of Sf9 cells expressing the gDs possessed a high titer of virus-neutralizing (VN) activities against CHV. These results indicated that the deletion of 4 amino acids possessing approximately 4 kDa of glyco-chain from gD of CHV in mammalian cells does not affect HA activity and VN antibody-inducing activity and that this deletion of gD(YP11mu) might be a good selective marker for development of recombinant viruses as a live vaccine.
