ニュージーランド産IgG含有ウシ生乳由来乳清タンパクに存在する新型コロナウイルスSARS-CoV-2スパイクタンパク抗体

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 Kirikaea^1,*

1. Department of Microbiology, Juntendo University School of Medicine, Tokyo, Japan
2. Tochigi Prefectural Institute of Public Health and Environmental Science, Utsunomiya, Tochigi, Japan
3. Microbiology Research Division, Kohjin Bio Co., Ltd., Saitama, Japan
4. Aotearoa Co., Ltd., Tokyo, Japan

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.