Therapy of human non-small-cell lung carcinoma using antibody targeting of a modified superantigen.
Superantigens activate T-cells by linking the T-cell receptor to MHC class II on antigen-presenting cells, and novel reactivity can be introduced by fusing the superantigen to a targeting molecule. Thus, an antibody-targeted superantigen, which activates T cells to destroy tumour cells, might be used as cancer therapy. A suitable target is the 5T4 oncofetal antigen, which is expressed on many carcinomas. We constructed a fusion protein from a Fab of a monoclonal antibody recognizing the 5T4 antigen, and an engineered superantigen. The recombinant product 5T4FabV13-SEA(D227A)bound the 5T4 antigen expressed on the human non-small-cell lung cancer cell line Calu-1 with a Kd of 1.2 nM while the substitution of Asp227 to Ala in the superantigen moiety reduced binding activity to MHC class II. 5T4FabV13-SEA(D227A)tumour reactivity was demonstrated in 7/7 NSCLC samples by immunohistochemistry, while normal tissue reactivity was low to moderate. 5T4FabV13-SEA(D227A)induced significant T-cell-dependent in vitro killing of sensitive 5T4 bearing Calu-1 cells, with maximum lysis at 10(-10)M, while the capacity to lyse MHC class II expressing cells was approximately 1000 times less effective. Immunotherapy of 5T4FabV13-SEA(D227A)against human NSCLC was investigated in SCID mice reconstituted with human peripheral blood mononuclear cells. Mice carrying intreperitoneally growing Calu-1 cells showed significant reduction in tumour mass and number after intravenous therapy with 5T4FabV13-SEA(D227A). Thus, 5T4FabV13-SEA(D227A)has highly attractive properties for therapy of human NSCLC.
Forsberg
G
G
Active Biotech Research AB, Box 724, 220 07 Lund, Sweden.
Ohlsson
L
L
Brodin
T
T
Björk
P
P
Lando
P A
PA
Shaw
D
D
Stern
P L
PL
Dohlsten
M
M
D000818:Animals; D000937:Antigen-Antibody Reactions / Q000276:immunology; D000951:Antigens, Neoplasm / Q000276:immunology; D002289:Carcinoma, Non-Small-Cell Lung / Q000276:immunology / Q000628:therapy*; D003001:Cloning, Molecular; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007128:Immunoglobulin Fragments / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D007150:Immunohistochemistry; D007167:Immunotherapy / Q000379:methods*; D008175:Lung Neoplasms / Q000276:immunology / Q000628:therapy*; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D016513:Mice, SCID; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D018089:Superantigens / Q000276:immunology* / Q000494:pharmacology; D023041:Xenograft Model Antitumor Assays
D000951:Antigens, Neoplasm; D016207:Cytokines; D000949:Histocompatibility Antigens Class II; D007128:Immunoglobulin Fragments; D008562:Membrane Glycoproteins; D011993:Recombinant Fusion Proteins; D018089:Superantigens; C063709:trophoblastic glycoprotein 5T4, human