Bispecific scfv immunofusion (bif)

Abstract

Certain embodiments are directed to a bispecific immunoglobulin that is capable of binding cell surface molecules on a target cell, such as cancer cells, and cell surface molecules on immune effector cell, such as cytotoxic T lymphocytes, resulting in the targeted killing of target cells.

1 . A polypeptide comprising a first target binding domain that specifically binds a cancer cell, a second effector binding domain that specifically binds an immunologic effector, and an immunoglobulin constant region linker operatively coupling the first and second binding domain. 
     
     
         2 . The polypeptide of  claim 1 , wherein the target binding domain binds a colorectal, lung, breast, kidney, brain, prostate, pancreas, or blood cancer cell or solid malignant tumor cell. 
     
     
         3 . The polypeptide of  claim 2 , wherein the target binding domain binds a leukemia cell. 
     
     
         4 . The polypeptide of  claim 3 , wherein the target binding domain specifically binds cells expressing CD123, prostate specific membrane antigen (PSMA), TEM8, or CD33. 
     
     
         5 . The polypeptide of  claim 4 , wherein the target binding domain specifically binds CD123. 
     
     
         6 . The polypeptide of  claim 5 , wherein the target binding domain comprises variable regions that are 95% identical to variable regions of SEQ ID NO:2. 
     
     
         7 . The polypeptide of  claim 5 , wherein the target binding domain comprises variable regions having an amino acid sequence of the variable regions of SEQ ID NO:2. 
     
     
         8 . The polypeptide of  claim 1 , wherein the target binding domain has the amino sequence of SEQ ID NO:2. 
     
     
         9 . The polypeptide of  claim 1 , wherein the immune effector is a lymphocyte. 
     
     
         10 . The polypeptide of  claim 9 , wherein the lymphocyte is a CD3+ cytotoxic T lymphocyte. 
     
     
         11 . The polypeptide of  claim 1 , wherein the effector binding domain specifically binds CD3. 
     
     
         12 . The polypeptide of  claim 11 , wherein the effector binding domain comprises hypervariable regions that are 95% identical to the hypervariable regions of SEQ ID NO:3. 
     
     
         13 . The polypeptide of  claim 11 , wherein the effector binding domain comprises hypervariable regions having an amino acid sequence identical to SEQ ID NO:3. 
     
     
         14 . The polypeptide of  claim 1 , wherein the immunoglobulin constant region is a human IgG constant region. 
     
     
         15 . The polypeptide of  claim 14 , wherein the human IgG constant region is a hinge-C H 2-C H 3 segment of human IgG1. 
     
     
         16 . The polypeptide of  claim 14 , wherein the immunoglobulin constant region has an amino acid sequence that is 95% identical to SEQ ID NO:4. 
     
     
         17 . The polypeptide of  claim 14 , wherein the immunoglobulin constant region has an amino acid sequence identical to SEQ ID NO:4. 
     
     
         18 . A polypeptide having an amino acid sequence that is 90% identical to SEQ ID NO:1. 
     
     
         19 . A method for treating cancer comprising providing an effective amount of the polypeptide of  claim 1  to a cancer patient.