Abstract: This disclosure relates generally to human ACE2 polypeptides that exhibit enhanced binding to the S protein of SARS-CoV-2, or increased affinity, that can be used as therapeutic agents in combination with monoclonal antibodies for the prophylaxis (pre- or post-exposure prophylaxis), or treatment of COVID-19, or disease caused by any coronavirus that utilizes ACE2 as a cellular receptor.

Abstract: The modified polypeptides include at least one amino acid substitution that allows the polypeptide to bind better to the S surface glycoprotein of coronaviruses that use ACE2 as a cell entry receptor, either through direct increases in affinity or through improved folding and expression of ACE2. Use of the modified ACE2 polypeptides for inhibiting CoV entry, replication and/or spread, for pre-exposure and post-exposure CoV prophylaxis, and for treating a CoV infection (e.g. COVTD-19), is also described.

Abstract: Isolated polypeptides having enhanced affinity for a PDGF receptor and/or a VEGF receptor are provided. Compositions comprising the polypeptides and methods of use thereof are also provided.

Abstract: Modified platelet-derived growth factor receptor alpha (PDGFR?) polypeptides are described. The modified polypeptides include at least one amino acid substitution that allows the polypeptide to retain the capacity to bind a cytomegalovirus (CMV) trimer comprised of glycoprotein H (gH), gL and gO, but leads to reduced binding to one or more platelet-derived growth factor (PDGF) ligands. Use of the modified PDGFR? polypeptides for inhibiting CMV replication and/or spread, or treating a CMV infection, is also described.

Abstract: Provided herein are HIV-1 Env proteins or fragments thereof comprising one or more amino acid mutations; and nucleic acid molecule encoding the same. Further provided is a method of screening a compound for binding to one or more mutant HIV-1 Env proteins; and methods for eliciting an immune response against an HIV-1 infected cell, comprising administering to a subject an amount of a mutant HIV-1 Env protein, a fragment thereof a mutant HIV-1 Env trimeric complex, or portion thereof, effective to elicit an immune response in the subject. Further provided is a pharmaceutical composition, such as a vaccine, comprising the mutant HIV-1 Env protein or fragment thereof.

Abstract: The present invention provides designed polypeptides that selectively bind to and inhibit Epstein Barr protein BHFR1, and B cell lymphoma family proteins, and are thus useful for treating Epstein Barr-related diseases and cancer.