virus (1) substitution (1) protéine (1) infection (1) acide aminé (1) champ (1) comparaison (1) ligne (1) Comparison (1) Propagation (1) Continuous cell lines (1) Viruses--Isolation (1) Will (1) Volumetric analysis (1) Tonsils (1) Tissues (1) Proteins (1) Nose (1) Macrophages (1) Lungs (1) Infection (1) Growth (1) Expression (1) Cells (1) Cell lines (1) Porcine reproductive and respiratory syndrome (1) Receptors (1) Residues (1) Will (1) Susceptibility (1)