A human-mouse chimeric Lym-1 monoclonal antibody with specificity for human lymphomas expressed in a baculovirus system.

Abstract

A murine anti-human B-cell monoclonal antibody, Lym-1, has shown considerable promise for the treatment of human malignant lymphomas and has been utilized as a new radioimmunotherapy for refractory lymphoma. In order to enhance its clinical potential, a genetically engineered chimeric Lym-1 (chLym-1) with murine variable regions and human gamma 1 and kappa constant regions was constructed and expressed. The goal of this study was to generate a Lym-1 reagent with decreased immunogenicity and improved effector functions. Murine Lym-1 variable region cDNAs were isolated from the murine Lym-1 hybridoma cell line, fused to gamma 1 and kappa constant region cDNAs, and expressed in an insect cell expression system with the baculovirus transfer vector pAcUW31. The chLym-1 antibody expressed in this system was correctly processed and assembled into the expected immunoglobulin monomer. Chimeric Lym-1 bound to both target antigen-bearing Raji cells and a Lym-1 anti-idiotype antibody and had a similar binding affinity as murine Lym-1. The chimeric and murine versions of Lym-1 were assayed for their ability to mediate antibody-dependent cellular cytotoxicity (ADCC) and to induce complement-mediated cytotoxicity (CMC) against Raji targets. Chimeric Lym-1 mediated a two-fold higher level of ADCC than murine Lym-1 and slightly lower levels of CMC than murine Lym-1. In addition, in Raji lymphoma-bearing nude mice, chLym-1 localized to the tumor with approximately equal uptake at 24 and 72 hours. Chimeric Lym-1, however, cleared from the blood of nontumor-bearing mice approximately 5 times faster than murine Lym-1 (20 h vs. 5 days), as expected for a xenogeneic protein. The improved in vitro and in vivo activities of this genetically engineered monoclonal antibody render it a new potential immunotherapeutic reagent for the treatment of human malignant lymphomas.

• Authors: P Hu, M S Glasky, A Yun, M M Alauddin, J L Hornick, L A Khawli, A L Epstein
• Journal: Human antibodies and hybridomas (Hum Antibodies Hybridomas) Vol. 6 Issue 2 Pg. 57-67 ( 1995) ISSN: 0956-960X [Print] United States
• PMID: 7492752 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Antibodies, Anti-Idiotypic
• Antibodies, Monoclonal
• Antibodies, Neoplasm
• DNA Primers
• Immunoglobulin Idiotypes
• Recombinant Fusion Proteins
• Recombinant Proteins

Topics

• Animals
• Antibodies, Anti-Idiotypic (immunology)
• Antibodies, Monoclonal (immunology)
• Antibodies, Neoplasm (immunology, metabolism)
• Antibody Affinity
• Antibody-Dependent Cell Cytotoxicity
• Base Sequence
• DNA Primers (chemistry)
• Genetic Vectors
• Humans
• Immunoglobulin Idiotypes (immunology)
• Lymphoma (immunology)
• Mice
• Mice, Nude
• Molecular Sequence Data
• Neoplasm Transplantation
• Nucleopolyhedroviruses (genetics)
• Recombinant Fusion Proteins (pharmacokinetics)
• Recombinant Proteins (pharmacokinetics)
• Spodoptera