Antibody for 3′-isoLM1 and 3′,6′-iso-LD1 gangliosides

Inventors

Bigner, Darell • Kuan, Chien-Tsun • Pastan, Ira H. • Piao, Hailan

Assignees

UNITED STATES GOVERNMENT HEALTH AND HUMAN SERVICES (NIH), Secretary of, Department of • Duke University • US Department of Health and Human Services

Abstract

High affinity antibodies were made to gangliosides expressed on tumor cells. The antibodies can be used analytically, diagnostically, therapeutically, and theranostically. The antibodies may be used to target cytotoxic reagents to tumor cells, thus minimizing full-body toxicity. The antibodies may also be used with out added cytotoxin. The antibodies may be detectably labeled or labelable for analytic and diagnostic purposes. The combination of specificity and affinity of the antibodies render them particularly useful.

Core Innovation

The invention provides high-affinity antibodies to gangliosides expressed on tumor cells, specifically targeting 3′-isoLM1 and 3′,6′-isoLD1 gangliosides. These antibodies exhibit improved specificity and affinity, with some binding preferentially to 3′,6′-isoLD1 over 3′-isoLM1, and do not bind to a range of other gangliosides including isoLA1, Fuc3′-isoLM1, 3′-LM1, 3′,8′-LD1, and others. The antibodies may be monoclonal IgG, including IgG1, IgG2, IgG3, or IgG4, or isolated antibody constructs comprising specific complementarity determining regions (CDRs) such as VHCDR2 and VLCDR1. They can be produced by hybridoma technology or recombinant methods and may be used as single-chain variable fragments (scFv) or fused with cytotoxic moieties for therapeutic applications.

The antibodies are useful analytically, diagnostically, therapeutically, and theranostically, including as agents to target cytotoxic reagents to tumor cells while minimizing full-body toxicity. They can be detectably labeled for analytic and diagnostic purposes such as immunohistochemistry, ELISA, or flow cytometry. The antibodies demonstrate specificity for lacto-series gangliosides on glioblastoma and other tumor cell surfaces, overcoming prior difficulties in generating high-affinity IgG antibodies to such gangliosides because of poor immunogenicity and tolerance.

The problem solved is the difficulty in producing high-affinity IgG antibodies to major brain gangliosides, especially lacto-series gangliosides like 3′-isoLM1 and 3′,6′-isoLD1, which are expressed in human gliomas including glioblastoma. Previous monoclonal antibodies were predominantly low-affinity IgM subclass. Existing antibodies lacked sufficient specificity and affinity for effective therapeutic use. By immunizing β3Gn-T5 knockout mice, which lack complex gangliosides and are immunologically naive to them, and using efficient hybridoma production via Sendai virus, the invention achieves high-affinity IgG antibodies specifically recognizing these gangliosides with minimal cross-reactivity, enabling effective targeting and potential treatment of brain tumors.

Claims Coverage

The patent includes one independent claim defining an isolated antibody construct with specific binding properties and multiple dependent claims detailing related features.

The claims cover isolated antibody constructs with specific amino acid sequences binding 3′-isoLM1 and 3′,6′-isoLD1 gangliosides, including embodiments where these constructs are conjugated to cytotoxic moieties such as Pseudomonas exotoxin A or its truncated forms, enabling targeted therapeutic applications.

Stated Advantages

Documented Applications