The extracellular domain of the ovIFNAR2 subunit (R2E) has intrinsic AV
activity. (A) ovIFN-τ4 was diluted from left to right
in a 1:3 series. (B) Thrombin-cleaved GST-R2E was
diluted from top to bottom in a 1:3 series. (C) The
treatments were combined (ovIFN-τ4, left to right; R2E, top to
bottom). Protected cell monolayers take up the Gentian violet stain.
(D) A comparison of the effects of R2E, GST-R2e, R1e,
and ovIFN-τ4 on MDBK cells (Top), mouse L929 cells
(Middle), and L929 cells stably transfected with a
chimeric receptor (R2C) containing the extracellular domain of ovIFNAR2
(19) and the intracellular domain of huIFNAR2c (24)
(Bottom).