Figure 1

Plaque latitude and penetration depth underneath the basement membrane (BM) of PRV(89V87) plaques at 20 h pi in mock-treated (white bars) and protease inhibitor-treated (marked bars) porcine nasal respiratory mucosa explants. Explants were treated with a broad-spectrum protease inhibitor cocktail (complete Mini), inhibiting serine, cysteine and metalloproteases, or with an aspartyl protease inhibitor, pepstatin A, at 1 h pi until sampling. Data are represented as means of 10 plaques of duplicate independent experiments + SD (error bars).