BVDV E(rns) Recombinant Rabbit mAb (SDT-4047-237)

BVDV E(rns) is a multifunctional envelope glycoprotein unique to pestiviruses, carrying intrinsic ribonuclease activity and serving as a core biomarker for bovine viral diarrhea virus diagnosis. Its relatively conserved sequence across BVDV genotypes and stable expression in persistently infected (PI) animals make E(rns) a preferred antigen for both antigen-capture and antibody ELISA platforms. E(rns)-based antigen assays are widely used for ear-notch screening of PI calves, which represent the major viral reservoir in cattle herds. Unlike some other viral antigens, E(rns) remains detectable even in pre-colostral samples, enabling early identification of PI newborns before maternal antibody interference develops.

As a serological antigen, recombinant E(rns) detects BVDV-specific antibodies and supports herd-level seroprevalence surveillance. However, cross-reactivity with other pestiviruses including classical swine fever virus restricts its standalone use for species differentiation. In addition, point mutations in the E(rns) coding region of field isolates may cause false-negative results when assays rely on limited monoclonal antibody panels. Compared with E2, E(rns) is less dominant for neutralizing antibody detection, so it is often combined with E2 or molecular assays to improve diagnostic confidence. Overall, E(rns) occupies an irreplaceable position in BVDV eradication programs, especially for large-scale PI animal screening, while combined testing strategies are recommended to mitigate specificity and mutation-related limitations.