Directed Engagement Of Activating Fc Receptors

Abstract

The present invention features engineered proteins that include a first polypeptide that specifically binds a first target (e.g., a cellular target, such as a cell-surface antigen) and a second polypeptide that selectively binds an activating FcR.

1 - 50 . (canceled) 
     
     
         51 . An isolated nucleic acid comprising a sequence encoding a protein comprising a variant fibronectin 3 (Fn3) domain amino acid sequence that is at least 70% identical to SEQ ID NO:1 and specifically binds an activating Fc gamma receptor IIA or IIIA, wherein the variant Fn3 domain comprises the amino acid sequence of the BC domain, the DE domain, and the FG domain of any one of any one of SEQ ID NOs: 2-35. 
     
     
         52 . An expression vector comprising the nucleic acid of  claim 51 . 
     
     
         53 . The expression vector of  claim 52 , further comprising a regulatory sequence. 
     
     
         54 . A host cell comprising the expression vector of  claim 53 . 
     
     
         55 . (canceled) 
     
     
         56 . A method of treating a patient diagnosed as having cancer, the method comprising administering to the patient the engineered protein encoded by the nucleic acid of  claim 59 , wherein the polypeptide that specifically binds a cellular target is a part of an immunoglobulin that specifically binds a cancer antigen expressed in the patient. 
     
     
         57 - 58 . (canceled) 
     
     
         59 . The nucleic acid of  claim 51 , wherein the protein is an engineered protein comprising the variant Fn3 domain and a polypeptide that specifically binds a cellular target. 
     
     
         60 . The nucleic acid of  claim 59 , wherein the polypeptide that specifically binds a cellular target is selected from a mutant lipocalin or cellular-target-binding fragment thereof; a Knottin; a peptide aptamer; a target derived from a Kunitz-type inhibitor; or an immunoglobulin, or an antigen-binding fragment thereof. 
     
     
         61 . The nucleic acid of  claim 60 , wherein the polypeptide that specifically binds a cellular target is an immunoglobulin, or an antigen-binding fragment thereof, wherein the immunoglobulin is an IgG1. 
     
     
         62 . The nucleic acid of  claim 61 , wherein the immunoglobulin or antigen-binding fragment is abciximab, adalimumab, alemtuzumab, basiliximab, bevacizumab, certuximab, certolizumab pegol, daclizumab, eculizumab, efalizumab, gentuzumab, ibritumomab tiuxetan, infliximab, muromonab-CD3, natalizumab, omalizumab, palivisumab, panitumumab, ranibizumab, rituximab, tositumomab, or trastuzumab. 
     
     
         63 . The nucleic acid of  claim 51 , wherein the variant Fn3 domain specifically binds an activating Fc receptor IIA or IIIA and comprises the amino acid sequence of the BC domain, the DE domain, and the FG domain of any one of SEQ ID NOs: 2, 3, 4, or 5. 
     
     
         64 . The nucleic acid of  claim 63 , wherein the variant Fn3 domain comprises the amino acid sequence of any one of SEQ ID NOs: 2, 3, 4, or 5. 
     
     
         65 . The nucleic acid of  claim 63 , wherein the protein is an engineered protein comprising the variant Fn3 domain and a polypeptide that specifically binds a cellular target. 
     
     
         66 . The nucleic acid of  claim 51 , wherein the variant Fn3 domain specifically binds an activating Fc receptor IIA or IIIA and comprises the amino acid sequence of the BC domain, the DE domain, and the FG domain of any one of SEQ ID NOs: 6-15. 
     
     
         67 . The nucleic acid of  claim 66 , wherein the variant Fn3 domain comprises the amino acid sequence of any one of SEQ ID NOs: 6-15. 
     
     
         68 . The nucleic acid of  claim 66 , wherein the protein is an engineered protein comprising the variant Fn3 domain and a polypeptide that specifically binds a cellular target. 
     
     
         69 . The nucleic acid of  claim 51  wherein the variant Fn3 domain specifically binds an activating Fc receptor IIA or IIIA and comprises the amino acid sequence of the BC domain, the DE domain, and the FG domain of any one of SEQ ID NOs: 16-35. 
     
     
         70 . The nucleic acid of  claim 69 , wherein the variant Fn3 domain comprises the amino acid sequence of any one of SEQ ID NOs: 16-35. 
     
     
         71 . The nucleic acid of  claim 69 , wherein the protein is an engineered protein comprising the variant Fn3 domain and a polypeptide that specifically binds a cellular target. 
     
     
         72 . An isolated protein comprising a variant fibronectin 3 (Fn3) domain amino acid sequence that is at least 70% identical to SEQ ID NO:1 and specifically binds an activating Fc gamma receptor IIA or IIIA, wherein the variant Fn3 domain comprises the amino acid sequence of the BC domain, the DE domain, and the FG domain of any one of any one of SEQ ID NOs: 2-35. 
     
     
         73 . The isolated protein of  claim 72 , wherein the protein is an engineered protein comprising the variant fibronectin 3 (Fn3) domain linked to the C-terminus of a heterologous amino acid sequence that specifically binds a cellular target other than activating Fc gamma receptor IIA or IIIA.