Expression and purification of two anti-CD19 single chain Fv fragments for targeting of liposomes to CD19-expressing cells.
Antibody-targeted liposomal anticancer drugs combine the specificity of antibodies with large payloads of entrapped drugs. We previously showed that liposomal doxorubicin (DXR) targeted via anti-CD19 monoclonal antibodies (mAb) or their Fab' fragments against the B-cell antigen CD19 led to improved therapeutic effects in murine B-cell lymphoma models relative to non-targeted liposomal DXR. We now are examining the use of anti-CD19 single chain fragments of the antibody variable region (scFv) as a targeting moiety, to test the hypothesis that scFv have advantages over full-sized mAb or Fab' fragments. We expressed two different anti-CD19 scFv constructs, HD37-C and HD37-CCH in E. coli, and purified the scFvs using two different methods. The HD37-CCH construct was selected for coupling studies due to its relative stability and activity in comparison to HD37-C. When coupled to liposomes, the HD37-CCH scFv showed increased binding in vitro to CD19-positive Raji cells, compared to non-targeted liposomes. Cytotoxicity data showed that HD37-CCH scFv-targeted liposomes loaded with DXR were more cytotoxic than non-targeted liposomal DXR. Our results suggest that anti-CD19 scFv constructs should be explored further for their potential in treating B-lymphoid leukemias and lymphomas.
Cheng
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WW
Dept. of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada T6G 2H7.
Das
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Suresh
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Allen
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TM
D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D000911:Antibodies, Monoclonal / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D000915:Antibody Affinity; D018941:Antigens, CD19 / Q000276:immunology* / Q000378:metabolism; D000951:Antigens, Neoplasm / Q000276:immunology* / Q000378:metabolism; D001666:Binding Sites, Antibody; D002051:Burkitt Lymphoma / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002626:Chemistry, Pharmaceutical; D003001:Cloning, Molecular; D004317:Doxorubicin / Q000494:pharmacology*; D004339:Drug Compounding; D016503:Drug Delivery Systems; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology; D007135:Immunoglobulin Variable Region / Q000276:immunology* / Q000378:metabolism; D020128:Inhibitory Concentration 50; D008081:Liposomes
D000903:Antibiotics, Antineoplastic; D000911:Antibodies, Monoclonal; D018941:Antigens, CD19; D000951:Antigens, Neoplasm; D007140:Immunoglobulin Fab Fragments; D007135:Immunoglobulin Variable Region; D008081:Liposomes; D004317:Doxorubicin