Figure 1

Plaque forming assay of VN1194-W, VN1194-P and other variants isolated from VN1194. Confluent monolayer of MDCK cells were inoculated with 10-fold serial dilutions of H5N1 virus and overlaid with 1% hypo-Tm-solved agarose. After two d inoculation at 35°C, cells were stained with neutral red and plaque morphology was evaluated. The larger plaques were discriminated from smaller plaques when their size was two times larger than smaller ones. A: VN1194-W; B: VN1194-P; C: 1194-SP; D: 1194-LP; E: 1194-ML; F: 1194-MB.