Prevention of influenza by targeting host receptors using engineered proteins

Abstract

Significance We have developed a new class of host-targeted biologics to prevent influenza by engineering multivalent carbohydrate-binding modules that bind with high affinity to sialic acid, the critical component of the influenza virus cell surface receptor. Mouse studies reveal a remarkable efficacy: a single 1-μg dose of the lead biologic given 7 d before a lethal challenge with 2009 pandemic H1N1 influenza virus provides complete protection. This new approach has the potential to be a front-line defense against any current and future influenza virus, overcoming viral escape to vaccines and antivirals. In addition, the biologics may have broader application against other respiratory pathogens.

Sialic Acid-Binding Protein Sp 2CBMTD Protects Mice against Lethal Challenge with Emerging Influenza A (H7N9) Virus

“…Therefore, Sp2CBMTD, which was designed to mask SA-containing host cell receptors, is a promising candidate. Unlike the investigational antiviral biologic DAS181, Sp2CBMTD does not remove cellular receptors; instead it masks them and prevents viral attachment (21). Glycan array screening shows that SpCBM recognizes glycans containing terminal ␣2,3-or ␣2,6-linked SA (20), emphasizing the feasibility of a biologic that can bind to receptors in the upper and lower respiratory tract of humans.…”

“…Madin-Darby canine kidney (MDCK) cells were obtained from the American Type Culture Collection and maintained as described previously (22). Sp2CBMTD was generated by PCR-based cloning techniques, using genes encoding the carbohydrate-binding module 40 (CBM40) domain from Streptococcus pneumoniae NanA sialidase and the trimerization domain from Pseudomonas aeruginosa pseudaminidase (21). The experiments with the H7N9 and H5N1 influenza viruses were conducted in an animal biosafety level 3ϩ containment facility approved by the U.S. Department of Agriculture.…”

“…Serum samples were obtained 21 days after H7N9 or H5N1 virus infection, treated with receptor-destroying enzyme (Denka Seiken Co.), heat inactivated at 56°C for 1 h, and tested for the presence of antihemagglutinin (HA) antibodies by the HA inhibition assay with 0.5% turkey red blood cells (Rockland Immunochemicals). The presence of anti-SpCBM antibodies in the serum samples was measured in an enzyme-linked immunosorbent assay (ELISA), using purified protein (1 g/well) immobilized on 96-well plates (Corning) (21).…”

“…By using structural information, Connaris, Crocker, and Taylor (20) and Connaris et al (21) recently developed multivalent proteins based on SA-recognizing carbohydrate-binding modules (mCBMs) derived from bacterial sialidases with high affinity to SA receptors (Vc2CBMTD and Sp2CBMTD) (20,21 (21). The biologics appear to stimulate inflammatory mediators that confer protective ability in mice (21).…”

“…The biologics appear to stimulate inflammatory mediators that confer protective ability in mice (21). Human infections with zoonotic viruses circulating in natural reservoirs are introducing additional challenges for controlling infection because of the uncertainty about virus pathogenicity to humans and disease severity.…”