Establishment of latency associated with glycoprotein E (gE) seroconversion after bovine herpesvirus 1 infection in calves with high levels of passive antibodies lacking gE antibodies.
This study was conducted to investigate the glycoprotein E (gE) antibody response raised after inoculation with a low infectious dose of bovine herpesvirus 1 (BHV-1) in six calves possessing high levels of passive immunity from cows repeatedly vaccinated with gE deleted marker vaccine. Four out of the six calves developed gE antibodies 3-5 weeks after infection, whereas the two other ones remained seronegative to gE. After 5 months of infection, the six calves were treated with dexamethasone. Virus was only re-excreted by the four calves which previously seroconverted against gE. The two other calves became seronegative against BHV-1, 30-32 weeks after infection. A second dexamethasone treatment performed 11 months after infection failed to demonstrate a latent infection in these two calves. Moreover, the lack of identification of a cell-mediated immune response, after the two dexamethasone treatments, and the failure to detect BHV-1 DNA sequences in trigeminal ganglia strongly suggest that these two calves were not latently infected. In conclusion, the presence of high levels of maternal immunity lacking gE antibodies does not prevent latency after infection with a low titre of BHV-1. Moreover, latency is associated with a serological response to gE. These results confirm that the gE deletion is a good marker to identify young calves latently infected with a field virus.
Schynts
F
F
Laboratory of Virology, Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, University of Liège, B43bis, B-4000, Liège, Belgium.
Lemaire
M
M
Ros
C
C
Belak
S
S
Thiry
E
E
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D000914:Antibodies, Viral / Q000097:blood*; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy / Q000276:immunology / Q000517:prevention & control*; D003126:Colostrum / Q000276:immunology; D004279:DNA, Viral / Q000032:analysis; D003907:Dexamethasone / Q000627:therapeutic use; D005260:Female; D006566:Herpesviridae Infections / Q000188:drug therapy / Q000517:prevention & control / Q000662:veterinary*; D007242:Herpesvirus 1, Bovine / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D007112:Immunity, Maternally-Acquired; D012668:Trigeminal Ganglion / Q000821:virology; D015164:Vaccines, Inactivated; D014759:Viral Envelope Proteins / Q000276:immunology*; D014764:Viral Proteins; D017735:Virus Latency; D017201:Virus Shedding
D000893:Anti-Inflammatory Agents; D000914:Antibodies, Viral; D004279:DNA, Viral; D015164:Vaccines, Inactivated; D014759:Viral Envelope Proteins; D014764:Viral Proteins; C046998:bovine herpesvirus type-1 glycoproteins; D003907:Dexamethasone