Characterization of chemokine-anttbody fusion proteins for cancer immunotherapy

The successful eradication of cancer cells during minimal residual disease may require the targeting of widely scattered tumor deposits, that may be sheltered from T cell or NK cell immune recognition by various adaptation pathways (downewgulation of Class I or II expression) and effector cell inhibitors such as TGF beta and interleukin-10 secretion. We describe here the construction of antibody fusion molecules with variable domains directed against her2neu, linked to sequences encoding the chemokine RANTES The latter was chosen because of its wide spectrum of biologic activity in recruiting T cells, NK cells monocytes and dendritic cells Moreover, RANTES has been shown to promote anti-tumor immune responses and abolish tumor establishment in syngeneic murine tumor models RANTES cDNA was amplified by PCR and cloned at the 5'-end of human her2ne heavy chain via (Gly4-Ser)3 flexible linker The expression vector of the light chain and heavy chain anti-her2ne fusion protein were transfected into Sp2/0 myeloma cells, and recombinant proteins purified. Fusion of RANTES to the antibody sequences did not alter antigen binding properties to her2neu transfectants and SKBR3 breast cancer cell line The chemokine avtivity of RANTES in these engineered fusion products was demonstrated using several assays: 1) F-actin polymerization of THP-1 cells treated with dBcAMP (1. 5 fold increase), 2) transwell and transendothelial migration of primary CD34+ cells and T lymphocytes Antibody fusion proteins may overcome limitations of standard antibody therapy and represents a novel and promising approach to the problem of minimal residual disease.