Protection of human ACE2 transgenic Syrian hamsters from SARS CoV-2 variants by human polyclonal IgG from hyper-immunized transchromosomic bovines

• Published in: bioRxiv
• Main Authors: Gilliland, Theron, Liu, Yanan, Li, Rong, Dunn, Matthew, Cottle, Emily, Terada, Yutaka, Ryckman, Zachary, Alcorn, Maria, Vasilatos, Shauna, Lundy, Jeneveve D, Larson, Deanna, Wu, Hua, Luke, Thomas, Bausch, Christoph, Egland, Kristi, Sullivan, Eddie, Wang, Zhongde, Klimstra, William
• Format: Paper Journal Article
• Language: English
• Published: Cold Spring Harbor Cold Spring Harbor Laboratory Press 26.07.2021; Cold Spring Harbor Laboratory
• Edition: 1.1
• Subjects: ACE2; Angiotensin-converting enzyme 2; Antibodies; Genotypes; Hyperimmunization; Immunoglobulin G; Lethality; Microbiology; Monoclonal antibodies; Pandemics; Patients; Plasmids; Proteins; Severe acute respiratory syndrome coronavirus 2; Spike protein; Strains (organisms); Virulence; United Kingdom > UK
• ISSN: 2692-8205; 2692-8205
• DOI: 10.1101/2021.07.26.453840

Pandemic SARS CoV-2 has been undergoing rapid evolution during spread throughout the world resulting in the emergence of many Spike protein variants, some of which appear to either evade antibody neutralization, transmit more efficiently, or potentially exhibit increased virulence. This raises significant concerns regarding the long-term efficacy of protection elicited after primary infection and/or from vaccines derived from single virus Spike (S) genotypes, as well as the efficacy of anti-S monoclonal antibody based therapeutics. Here, we used fully human polyclonal human IgG (SAB-185), derived from hyperimmunization of transchromosomic bovines with DNA plasmids encoding the SARS-CoV-2 Wa-1 strain S protein or purified ectodomain of S protein, to examine the neutralizing capacity of SAB-185 in vitro and the protective efficacy of passive SAB-185 antibody (Ab) transfer in vivo. The Ab preparation was tested for neutralization against five variant SARS-CoV-2 strains: Munich (Spike D614G), UK (B.1.1.7), Brazil (P.1) and SA (B.1.3.5) variants, and a variant isolated from a chronically infected immunocompromised patient (Spike del144-146). For the in vivo studies, we used a new human ACE2 (hACE2) transgenic Syrian hamster model that exhibits lethality after SARS-Cov-2 challenge and the Munich, UK, SA and del144-146 variants. SAB-185 neutralized each of the SARS-CoV-2 strains equivalently on Vero E6 cells, however, a control convalescent human serum sample was less effective at neutralizing the SA variant. In the hamster model, prophylactic SAB-185 treatment protected the hamsters from fatal disease and minimized clinical signs of infection. These results suggest that SAB-185 may be an effective treatment for patients infected with SARS CoV-2 variants. Competing Interest Statement Tom Luke, Hua Wu, Christoph Bausch, Kathi Egland and Eddie Sullivan are employees of SAB Biotherapeutics. The Klimstra laboratory has received contract support from SAB Biotherapeutics