Recombinant SARS-CoV-2 Spike protein in its homotrimeric form, containing S1+S2 subunits and encompassing amino acids 16-1213. This protein corresponds to SARS-CoV-2 Variant B.1.617.2, also known as variant Delta, originally discovered in India. It contains the eight Delta variant mutations indicated below in addition to deletion 156/157. The construct also contains mutations 682RRAR685>A, K986P and V987P, and a T4 trimerization domain followed by a His-tag (6xHis) in C-terminal. The recombinant protein was affinity purified.