Test Methods and Kits for Identifying Resistance or Susceptibility to Bovine Leukemia Virus (BLV)-Induced Persistent Lymphocytosis (PL)
This technology provides an accurate means for determining whether a cow is resistant to or susceptible to persistent lymphocytosis (PL). By determining this resistance, dairy and beef farmers may substantially improve the health and production of their herds as well as better protect consumers from potentially harmful food products. This technology consists of three major parts: A method for obtaining a DNA sample that includes the DRB3 gene exon 2 A method for identifying the specific polymorphism of the DRB3 gene A method for determining whether the polymorphism indicates resistance or susceptibility to PL, a subclinical stage of bovine leukemia virus (BLV)
Description/Details
Approximately 50% of cattle in the U.S. are infected with the bovine leukemia virus, an exogenous type C retrovirus. Approximately 5% of cattle infected with BLV go on to develop malignant lymphoma.
No treatment or vaccine for BLV exists. Successful elimination of BLV from herds has been achieved through testing and subsequent slaughtering of infected animals. While this is expensive, it is currently the only method for eliminating the virus. The technology described in this listing is a method and test kit for identifying bovines that are susceptible or resistant to BLV infections. It achieves this goal by determining whether an animal is resistant or susceptible to persistent lymphocytosis, a subclinical stage of BLV infection in cattle. PL is characterized by polyclonal expansion of BLV-infected B cells. PL occurs in approximately 30% of BLV-infected cattle and is controlled by the host's genetics.
This technology uses a unique technique called polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) typing. PCR-RFLP typing takes DNA samples that include a DRB3 gene exon 2, identifies the nucleotide of the gene, and determines whether the nucleotides contain codons that indicate those characteristics. It was found that PCR-RFLP was a rapid and sensitive method for detecting polymorphism in a particularly relevant part of the bovine lymphocyte antigen (BoLA) DRB3 gene.
It also uses a motif discrimination by product length (MDPL) technique that simplifies the identification of PL-resistant genes. Since polymorphism in the BoLA-DRB3 gene correlates to resistance or susceptibility of various bovine diseases, it is an excellent predictor of those characteristics. By determining resistance or susceptibility to PL at a genetic level, farmers can successfully eliminate BLV from their herds.
Applications
- Bovine breeders (e.g., genotypic selection and breeding cows with traits showing resistance to BLV)
- Beef farmers
- Dairy farmers
- Lab testing services (e.g., using the ELISA test kits for BLV)
Benefits
This method for determining resistance to PL can help farmers eliminate BLV from their herds. BLV is responsible for decreased milk production as well as poor reproductive performance. Simply and accurately determining resistance or susceptibility to PL can provide the following benefits: Improved dairy production Improved reproduction performance Healthier herds Safer products for human consumption (e.g., potential connection between consumption of BLV-contaminated food products and human breast cancer) Lower bovine death rate due to the BLV This technology also can be used to identify higher milk production qualities in dairy cows.