All other proteins that do not fall into our antibodies and enzymes classes are considered antigens or recombinant proteins. These include positive controls and bacterial and viral antigens. 

CBP_0017.1 PtX™ SUPATag- Saving U Positive Antigen View Datasheet

CB_0001.2 SARS-CoV-2 Spike Protein Receptor Binding Domain (RBD), Rabbit IgG Fc Tag View Datasheet
CB_0002.5 SARS-CoV-2 Spike Protein S1, His Tag View Datasheet