Our SARS Coronavirus Pseudoviral Particles are replication-deficient Maloneymurine Leukemia Virus (MLV or MuLV) pseudotyped with the SARS-CoV/BJ02 virus spike protein (Genbank Accession # AY278487). MLV-based virus system is a better choice than HIV-based lentivirus system for making pseudoviral particles in regards of lab safety and product quality. Gag-Pol is the only component from MLV.