Chimeric CLL-1 antibody fusion proteins containing granulocyte-macrophage colony-stimulating factor or interleukin-2 with specificity for B-cell malignancies exhibit enhanced effector functions while retaining tumor targeting properties.
Although monoclonal antibody (MoAb) therapy of the human malignant lymphomas has shown success in clinical trials, its full potential for the treatment of hematologic malignancies has yet to be realized. To expand the clinical potential of a promising human-mouse chimeric antihuman B-cell MoAb (chCLL-1) constructed using the variable domains cloned from the murine Lym-2 (muLym-2) hybridoma, fusion proteins containing granulocyte-macrophage colony-stimulating factor (GM-CSF) (chCLL-1/GM-CSF) or interleukin (IL)-2 (chCLL-1/IL-2) were generated and evaluated for in vitro cytotoxicity and in vivo tumor targeting. The glutamine synthetase gene amplification system was employed for high level expression of the recombinant fusion proteins. Antigenic specificity was confirmed by a competition radioimmunoassay against ARH-77 human myeloma cells. The activity of chCLL-1/GM-CSF was established by a colony formation assay, and the bioactivity of chCLL-1/IL-2 was confirmed by supporting the growth of an IL-2-dependent T-cell line. Antibody-dependent cellular cytotoxicity against ARH-77 target cells demonstrated that both fusion proteins mediate enhanced tumor cell lysis by human mononuclear cells. Finally, biodistribution and imaging studies in nude mice bearing ARH-77 xenografts indicated that the fusion proteins specifically target the tumors. These in vitro and in vivo data suggest that chCLL-1/GM-CSF and chCLL-1/IL-2 have potential as immunotherapeutic reagents for the treatment of B-cell malignancies.
Hornick
J L
JL
Department of Pathology, University of Southern California School of Medicine, Los Angeles 90033, USA.
Khawli
L A
LA
Hu
P
P
Lynch
M
M
Anderson
P M
PM
Epstein
A L
AL
D000818:Animals; D000911:Antibodies, Monoclonal / Q000235:genetics / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D000918:Antibody Specificity; D000920:Antibody-Dependent Cell Cytotoxicity; D005822:Genetic Vectors; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D006825:Hybridomas / Q000276:immunology; D007376:Interleukin-2 / Q000235:genetics / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D015448:Leukemia, B-Cell / Q000276:immunology* / Q000628:therapy; D016393:Lymphoma, B-Cell / Q000276:immunology* / Q000628:therapy; D051379:Mice; D008819:Mice, Nude; D009101:Multiple Myeloma / Q000000981:diagnostic imaging / Q000276:immunology / Q000473:pathology; D016719:Radioimmunodetection; D011993:Recombinant Fusion Proteins / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D014018:Tissue Distribution; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured; D014410:Tumor Stem Cell Assay
D000911:Antibodies, Monoclonal; D007376:Interleukin-2; D011993:Recombinant Fusion Proteins; D016178:Granulocyte-Macrophage Colony-Stimulating Factor