Figure 6. REP 9 disrupts virus-receptor binding.

(A) REP 9 blocks α-DG binding of LCMV but not laminin: LCMV cl-13 (10⁷ PFU/ml) (top panel) and mouse EHS laminin (10 μg/ml) were pre-incubated with the indicated concentrations of REP 9 and then added to nitrocellulose blots of immobilized α-DG. After 4 hours of incubation, bound virus was detected using mAb 83.6 anti-LCMVGP2 and an HRP-coupled secondary antibody using ECL. Bound laminin was detected with a polyclonal Ab anti-laminin-1 and an HRP-coupled secondary antibody (B) Blocking of LCMV and laminin binding to immobilized α-DG in ELISA: LCMV cl-13 (10⁷ PFU/ml) and EHS laminin (10 μg/ml) were pre-incubated with the indicated concentrations of REP 9 and then added to microtiter plates containing immobilized α-DG from rabbit skeletal muscle. Bound virus and laminin were detected using the antibody concentrations in (A) in a color reaction with ABTS substrate. OD (405) was measured in an ELISA reader and background binding to BSA subtracted (n = 3 ± SD). (C) REP 9 dissociates the LCMVGP/receptor complex. LCMV cl-13 (10⁷ PFU/ml) was bound to immobilized α-DG for 16 hours at 6 °C. After brief washing, the indicated concentrations of REP 9 or laminin-1 were added for 2 hours at room temperature and bound virus was detected as in (B).