Three antibodies directed against the DIII-lr neutralized infection of both populations of RVPs with relatively similar potency (Fig. 3a–c; 0.9-, 1.5-, and 4.5-fold reduction in neutralization sensitivity of furin-RVPs for mAbs E16 (p = 0.67), E24 (p = 0.06), and E49 (p = 0.01), respectively). Here, FURIN is linked to infection.