International Dairy Journal 2021 Jun;117:105002
Presence of antibodies against SARS-CoV-2 spike protein in bovine whey IgG enriched fraction
Satoshi Oshiro1, Tatsuya Tada1, Naeko Mizutani1, Keiji Funatogawa2, Jun-ichiro Sekiguchi3, Masao Takahashi4, Teruo Kirikaea1,*
Bovine whey IgG enriched fraction contains antibodies against various human bacterial pathogens. It contains antibodies against some viral antigens, including human respiratory syncytial virus and influenza virus. We investigated whether the IgG enriched fraction has cross-reactivity with IgG antibodies against SARS-CoV-2 spike (S) and nucleocapsid (N) proteins. The full-length and partial-length SARS-CoV-2 S, N, a recombinant protein of the receptor binding domain (RBD) and nine peptides covering the receptor binding motif (RBM) of S were prepared. Direct enzyme-linked immunosorbent assays were conducted using these recombinant proteins and peptides as coating antigens and revealed the IgG enriched fraction contained antibodies against partial-length S [amino acids (aa) 177-512, 288-512, 348-578, 387-516 and 408-664], full-length N (aa 1-419) and partial-length N (aa 1-120, 111-220, 1-220 and 210-419), two RBD peptides, covering aa 427-446 and 502-520 of S, and recombinant RBD of S. These results indicate IgG enriched fraction contains antibodies against SARS-CoV-2.