A lumpy skin disease virus deficient of an IL-10 gene homologue provides protective immunity against virulent capripoxvirus challenge in sheep and goats.
Sheep and goat pox continue to be important livestock diseases that pose a major threat to the livestock industry in many regions in Africa and Asia. Currently, several live attenuated vaccines are available and used in endemic countries to control these diseases. One of these is a partially attenuated strain of lumpy skin disease virus (LSDV), KS-1, which provides cross-protection against both sheep pox and goat pox. However, when used in highly stressed dairy cattle to protect against lumpy skin disease (LSD) the vaccine can cause clinical disease. In order to develop safer vaccines effective against all three diseases, a pathogenic strain of LSDV (Warmbaths [WB], South Africa) was attenuated by removing a putative virulence factor gene (IL-10-like) using gene knockout (KO) technology. This construct (LSDV WB005KO) was then evaluated as a vaccine for sheep and goats against virulent capripoxvirus challenge. Sheep and goats were vaccinated with the construct and the animals were observed for 21days. The vaccine appeared to be safe, and did not cause disease, although it induced minor inflammation at the injection site similar to that caused by other attenuated sheep and goat pox vaccines. In addition, no virus replication was detected in blood, oral or nasal swabs using real-time PCR following vaccination and low levels of neutralising antibodies were detected in both sheep and goats. Leukocytes isolated from vaccinated animals following vaccination elicited capripoxvirus-specific IFN-γ secretion, suggesting that immunity was also T-cell mediated. Following challenge with virulent capripoxvirus, vaccinated sheep and goats were found to be completely protected and exhibited no clinical disease. Furthermore, real-time PCR of blood samples at various time points suggested that viremia was absent in both groups of vaccinated animals, as opposed to capripoxvirus-related clinical disease and viremia observed in the unvaccinated animals. These findings suggest that this novel knockout strain of LSDV has potential as a vaccine to protect livestock against sheep pox and goat pox.
National Centre for Foreign Animal Disease, Canadian Food Inspection Agency, Winnipeg, MB, Canada.
Hani
H
Boshra
National Centre for Foreign Animal Disease, Canadian Food Inspection Agency, Winnipeg, MB, Canada.
Thang
T
Truong
National Centre for Foreign Animal Disease, Canadian Food Inspection Agency, Winnipeg, MB, Canada.
Charles
C
Nfon
CSIRO Biosecurity Flagship, Australian Animal Health Laboratory, Geelong, Australia.
Timothy R
TR
Bowden
Vaccine & Infectious Disease Organization, University of Saskatchewan, Saskatoon, SK, Canada.
Volker
V
Gerdts
Vaccine & Infectious Disease Organization, University of Saskatchewan, Saskatoon, SK, Canada; School of Public Health, University of Saskatchewan, Saskatoon, SK, Canada.
Suresh
S
Tikoo
University of Alberta, Edmonton, AB, Canada.
Lorne A
LA
Babiuk
ARC-Onderstepoort Veterinary Institute, Onderstepoort, South Africa.
Pravesh
P
Kara
ARC-Onderstepoort Veterinary Institute, Onderstepoort, South Africa.
Arshad
A
Mather
ARC-Onderstepoort Veterinary Institute, Onderstepoort, South Africa; Department Veterinary Tropical Diseases, Faculty Veterinary Science, University of Pretoria, South Africa.
David B
DB
Wallace
National Centre for Foreign Animal Disease, Canadian Food Inspection Agency, Winnipeg, MB, Canada; University of Manitoba, Winnipeg, MB, Canada. Electronic address: shawn.babiuk@inspection.gc.ca.
Shawn
S
Babiuk
D000818:Animals; D055786:Gene Knockout Techniques; D015511:Goat Diseases / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D006041:Goats; D007371:Interferon-gamma / Q000378:metabolism; D016753:Interleukin-10 / Q000172:deficiency*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008167:Lumpy skin disease virus / Q000235:genetics / Q000276:immunology*; D011213:Poxviridae Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D016019:Survival Analysis; D016896:Treatment Outcome; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014764:Viral Proteins / Q000235:genetics*; D014765:Viral Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D037521:Virulence Factors / Q000172:deficiency
D014613:Vaccines, Attenuated; D014764:Viral Proteins; D014765:Viral Vaccines; D037521:Virulence Factors; D016753:Interleukin-10; D007371:Interferon-gamma
Goat pox; Lumpy skin disease; Sheep pox; Vaccine