Equine herpesvirus 1 mutants devoid of glycoprotein B or M are apathogenic for mice but induce protection against challenge infection.
Equine herpesvirus 1 (EHV-1) mutants devoid of the open reading frames (ORFs) of either glycoprotein (g) B or M were constructed and tested for their immunogenic potential in a murine model of EHV-1 infection. The mutant viruses were engineered using the virulent EHV-1 strain RacL11 or the modified live vaccine strain RacH by inserting the Escherichia coli LacZ gene into the viral ORFs. RacL11-infected mice showed signs typical of an EHV-1 infection, whereas mice infected with the EHV-1 gB- or gM-negative mutants or with RacH did not develop disease. No difference in the pathogenic potential of RacL11 gB- and gM-negative viruses was observed after application of either phenotypically completed or negative viruses. However, revertant RacL11 viruses in which the gB or gM gene had been restored caused EHV-1-related symptoms that were indistinguishable from those induced by RacL11. Mice that had been immunized with phenotypically negative gB- and gM-deficient EHV-1 were challenged with the RacL11 virus 25 days after immunization. Mock-immunized mice developed EHV-1 disease and high virus loads in their lungs were observed. In contrast, mice developed not exhibit EHV-1-caused disease. It was concluded (i) that deletion of either gB or gM abolished the virulence of strain RacL11 and (ii) that immunization with gB- or gM-negative EHV-1 elicited a protective immunity that was reflected by both virus-neutralizing antibodies and EHV-1-specific T-cells in spleens of immunized mice.
Neubauer
A
A
Institute for Medical Microbiology, Infectious and Epidemic Diseases, Ludwig-Maximillians-Universität München, Germany.
Beer
M
M
Brandmüller
C
C
Kaaden
O R
OR
Osterrieder
N
N
D000818:Animals; D006566:Herpesviridae Infections / Q000276:immunology / Q000821:virology*; D004861:Herpesvirus 1, Equid / Q000235:genetics* / Q000276:immunology / Q000472:pathogenicity; D051379:Mice; D008807:Mice, Inbred BALB C; D009154:Mutation; D016366:Open Reading Frames / Q000235:genetics; D014759:Viral Envelope Proteins / Q000235:genetics*; D014765:Viral Vaccines
D014759:Viral Envelope Proteins; D014765:Viral Vaccines; C040495:glycoprotein B, Simplexvirus