Sequencing of a 15-kb Ehrlichia ruminantium clone and evaluation of the cpg1 open reading frame for protection against heartwater.
A 1.2 kb polymorphic fragment from the Gardel isolate of Ehrlichia (formerly Cowdria) ruminantium was used to isolate a 15kb clone from the E. ruminantium Welgevonden LambdaGEM-11 library. This clone, WL2EL1, was subcloned and sequenced. Eight open reading frames (ORFs) were identified. The ORF in WL2EL1 which contained the Welgevonden homologue of the 1.2 kb polymorphic fragment was designated Cowdria polymorphic gene 1 (cpg1). The cpg1 ORF was cloned into pCMViUB, a genetic vaccine vector. Mice and sheep were immunized with pCMViUB/cpg1 by intramuscular injection and gene gun inoculation. Although all of the immunized mice died, there was a trend for mice that received larger amounts of pCMViUB/cpg1 DNA to survive longer. Four out of five sheep immunized with the construct survived lethal challenge.
Louw
Elmarié
E
Molecular Biology Section, Onderstepoort Veterinary Institute, Pretoria, South Africa. elmarie@moon.ovi.ac.za
Brayton
K A
KA
Collins
N E
NE
Pretorius
A
A
Van Strijp
F
F
Allsopp
B A
BA
D000818:Animals; D001428:Bacterial Vaccines; D003001:Cloning, Molecular; D004306:Dose-Response Relationship, Immunologic; D016995:Ehrlichia ruminantium / Q000235:genetics* / Q000276:immunology*; D005798:Genes, Bacterial; D005822:Genetic Vectors; D006357:Heartwater Disease / Q000276:immunology / Q000517:prevention & control*; D051379:Mice; D008810:Mice, Inbred C57BL; D016366:Open Reading Frames / Q000235:genetics / Q000276:immunology*; D011110:Polymorphism, Genetic; D017385:Sequence Homology; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology / Q000517:prevention & control*; D014611:Vaccination / Q000662:veterinary
D001428:Bacterial Vaccines