Figure 1.

Antigen design. Schematic diagrams of the expression cassette for the fusion proteins (left panel). The antigens of interest were fused downstream of the mouse Ig heavy chain signal peptide (=SP) MGWSCIILFLVATATGVQC via a Gly4Ser linker (= G₄S) to a murine IgG2a Fc fragment with the mutations affecting binding to FcγRs indicated. HIV gp120 and SARS-CoV-2 RBD were cloned as antigens of interest and the expected quaternary structures of the expressed fusion proteins are shown (right panel).