The mouse monoclonal antibody is produced from a hybridoma resulting from fusion of SP2/0 myeloma and B-lymphocytes obtained from a mouse immunized with Spike RBD. The antibody is specific against the Beta (B.1.351) and Gamma (P.1) variant of SARS-CoV-2, and has no binding with the spike RBD of the wild type virus, the Alpha (B.1.1.7) variant, the Delta (B.1.617.2) variant and the Omicron (B.1.1.529, BA.2) variant.