Abstract: Provided herein are antibodies that are useful for treating SARS-CoV-2 infections in a subject. Also provided herein are compositions comprising one or more antibodies, methods of treatment comprising administering one or more antibodies, and kits comprising one or more antibodies.

Abstract: This invention relates to the incorporation of one, or more, heterologous antibody epitopes into the AB, EF, or CD structural loops of the constant heavy domain 3 (“CH3 domain”) of an engineered antibody or Fc-linked therapeutic agent. The heterologous epitopes serve as “epitope tags” that are specifically detectable by epitope tag-specific detector antibodies, irrespective of the tagged agent's target specificity. Therefore, the epitope tags are useful for the rapid detection of any tagged antibody or Fc-linked agent in biological samples, including samples, which also contain endogenous antibodies.