Cloning of a bovine interferon-alpha gene subfamily and comparisons between genetically engineered and leukocyte bovine interferons.

Bovine peripheral leukocytes were virally induced for interferon production, and an acid stable, SDS stable, antiviral activity was detected in the preparation. This bovine interferon (BoIFN) was tested for its ability to induce an antiviral state in various mammalian cells and was found to be specific to cells from bovine origin. The BoIFN cross reacts with antibodies against human IFN-alpha but these antibodies do not neutralize the bovine IFN activity. Leukocyte BoIFN exhibits polymorphism upon Affi-Gel Blue chromatography and SDS-PAGE (16k and 24K). The virally induced leukocytes produce a 13S mRNA which upon translation in oocytes yields an active IFN molecule. Bovine genomic library was constructed and screened for BoIFN-alpha sequences, using human IFN-alpha probes. From the clones isolated, five were found to represent distinct genes. Sequence analysis indicate that these genes are closely related (94% homology). One of these genes was expressed in E. coli under the control of trp promoter operator. The physicochemical and biological properties of the bacterial BoIFN-alpha product resemble those of a subpopulation of natural BoIFN.