First gene-edited calf with reduced susceptibility to a major viral pathogen

Abstract

Bovine viral diarrhea virus (BVDV) is one of the most important viruses affecting the health and well-being of bovine species throughout the world. Here, we used CRISPR-mediated homology-directed repair and somatic cell nuclear transfer to produce a live calf with a six amino acid substitution in the BVDV binding domain of bovine CD46. The result was a gene-edited calf with dramatically reduced susceptibility to infection as measured by reduced clinical signs and the lack of viral infection in white blood cells. The edited calf has no off-target edits and appears normal and healthy at 20 months of age without obvious adverse effects from the on-target edit. This precision bred, proof-of-concept animal provides the first evidence that intentional genome alterations in the CD46 gene may reduce the burden of BVDV-associated diseases in cattle and is consistent with our stepwise, in vitro and ex vivo experiments with cell lines and matched fetal clones.

Current status and future of gene engineering in livestock

“…Recently, the first gene-edited calf with resistance to a major viral pathogen, Bovine Viral Diarrhea Virus (BVDV), was successfully produced. BVDV is one of the significant viruses affecting the health and growth of cattle worldwide, ultimately leading to substantial economic losses ( 76 ).…”

Structure of Bovine CD46 Ectodomain

“…Pestiviruses are species-specific, and this has been shown to extend to CD46, with the expression of bovCD46 conferring increased susceptibility of porcine cells to BVDV [ 8 ]. It was shown that the deletion of the BVDV binding site on bovCD46 results in a vast reduction in BVDV cell entry events, but has little effect on cell surface motility [ 14 ], and that substituting six amino acids in the same domain dramatically reduced susceptibility to infection in a live calf [ 15 ].…”

New Genomic Techniques (NGT) in animals and their agri/food/feed products

“…In collaboration with two US universities and the USDA, Acceligen has produced a cloned NGT cow with reduced susceptibility to Bovine Viral Diarrhoea virus (BVDV). An SDN-3 18 bp substitution in the BVDV 'binding domain' gene (CD46) reduced susceptibility to infection, as measured by clinical signs and the lack of viral infection in white blood cells (Workman et al, 2023). Acceligen has additionally produced 'Thamani' Holsteins that have three stacked mutations: the slick coat mutation in the PRLR gene, in addition to targeted mutations in two candidate genes (FDX2, DHRS4) that are hypothesised to result in resistance to African Trypanosomiasis.…”

“…Tuli breeds into the Holstein breed (Laible et al, 2021), interspecies allele substitutions e.g. African warthog allele into domestic pig (Lillico et al, 2016), in addition to the substitution of an 18 bp sequence coding 6 amino acids that does not exist in the species or in a sexually compatible species (Workman et al, 2023). Likewise, the production of polled cattle necessitates the replacement of a 10 bp sequence in the horned allele of the polled gene with a 212 bp repeat sequence to mimic the naturally-occurring polled allele found in Celtic beef breeds.…”