We propose to purify SARS-CoV-2 proteins to build a plate or filter-based array for rapid assessment of antibody responses. Proteins will be expressed in E. coli and purified as recombinant proteins. The arrays will initially be constructed manually using a vacuum blot system or ELISA plates. If arrays prove useful, a robotic system will be retooled. In addition to proteins already under study, we would expand our library to include all of the smaller open reading frames, especially proteins E and M, which are 100% conserved with SARS. The SARS-CoV-2 proteome can be covered in a 30 protein array. These arrays would then be used to ask novel questions about the development of the immune response in different patient cohorts, including cancer patients.