id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-333264-jdvb8px4	Hanke, Leo	An alpaca nanobody neutralizes SARS-CoV-2 by blocking receptor interaction	2020-09-04		.txt	text/plain	6380	380	51	Here, we report the isolation and characterization of an alpaca-derived single domain antibody fragment, Ty1, that specifically targets the receptor binding domain (RBD) of the SARS-CoV-2 spike, directly preventing ACE2 engagement. While fusion to an Fc domain renders Ty1 extremely potent, Ty1 neutralizes SARS-CoV-2 spike pseudovirus as a 12.8 kDa nanobody, which can be expressed in high quantities in bacteria, presenting opportunities for manufacturing at scale. The S ectodomain was purified from filtered supernatant on Streptactin XT resin (IBA Lifesciences), followed by size-exclusion chromatography on a Superdex 200 in 5 mM Tris pH 8, 200 mM NaCl. The RBD domain (RVQ-VNF) of SARS-CoV-2 was cloned upstream of an enterokinase cleavage site and a human IgG1 Fc. This plasmid was used to transiently transfect FreeStyle 293F cells using the FreeStyle MAX reagent. Neutralizing nanobodies bind SARS-CoV-2 spike RBD and block interaction with ACE2	./cache/cord-333264-jdvb8px4.txt	./txt/cord-333264-jdvb8px4.txt