Submission Number: AND-4-25-21

Abstract Number: 361

ANTIVIRAL ACTIVITIES OF VARIOUS INTERFERON-TAU FORMS IN OVINE AND BOVINE CELL LINES.

Andrei P Alexenko, Alan D Ealy* and R Michael Roberts*

Departments of Animal Sciences and Biochemistry, University of Missouri, Columbia, MO ¹

Abstract:
Inteferon tau (IFN-) is expressed by the trophectoderm of ruminant conceptuses and acts on the endometrium during early pregnancy in such a way that allows for continuation of luteal function, thereby promoting maintenance of a pregnant state. The IFN-, like other IFN classes, are also potent antiviral (AV) agents. The AV of three ovine (ov)IFN- (4, 6d, 11), and one bovine (bo)IFN- (1a) were compared to determine whether activities differed across species (bovine vs ovine) and according to target cell type (epithelial, stromal). Cell lines chosen were MDBK (bovine epithelial kidney), BEND (bovine epithelial endometrium), BHFTE (ovine epithelial tongue) and SCP (ovine nonepithelial choroid plexus). Antiviral potency was defined as the lowest concentration of protein required to protect 50% of the cells in a monolayer from vesicular stomatitis virus-induced cytolysis. Individual IFN showed comparable activities across species, although individual potencies varied more than 10-fold. The potency of IFN-4 on the three epithelial lines, for example, was 0.28 pM on BEND, 0.74 pM on MDBK, 0.23 pM on BHFTE. Such cell line-dependent differences are likely due to differences in IFN receptor abundance. The relative potencies of AV on epithelial-derived cell lines differed over a 20-fold range with ovIFN-4ovIFN-6dboIFN-1a>ovIFN-11, while the order on choroid plexus cells was different (ovIFN-4>boIFN-1aovIFN-11>ovIFN-6d). The ability of these to extend estrous cycle length in ewes correlated best with AV activity on BEND cells. Therefore, absolute antiviral potencies of IFN are cell line-specific but the relative antiviral potencies of these IFN are similar across epithelial-derived cells and between bovine and ovine cells. Supported by USDA/NRI grant 96-35205-3766.

Keywords: Pregnancy Recognition, Embyo, Cattle, Sheep

This abstract is being presented at: 8:00 AM in session:
Preimplantation Embryo/Fetus