Advances in understanding immune response in dairy cattle

From the beginning, cattle have made important contributions to the field of immunology, including the development of the first Mycobacterium bovis BCG vaccine for human tuberculosis in 1921. In 1981 the first report of a biosynthesized polypeptide vaccine against Foot and Mouth Disease Virus (FMDV) using the VP3 protein expressed in Escherichia coli (E. coli) was made for cattle. Cattle also possess a substantial proportion of T cells expressing the γδ T-cell receptor which helped to elucidate the role of these unique cells in host defence. More recently, it was discovered that cattle produce antibodies with ultra-long Complementarity Determining Region (CDR) - 3. This seminal finding has allowed the production of bovine therapeutic broadly neutralizing antibodies with ultra-long CDRs to passively treat various virial infections in humans and play a key role in protecting cattle. This chapter will review advances in bovine immunology, particularly as it relates to dairy cattle.