GMab-1, a high-affinity anti-3′-isoLM1/3′,6′-isoLD1 IgG monoclonal antibody, raised in lacto-series ganglioside-defective knockout mice

The lacto-series gangliosides 3′-isoLM1 and 3′,6′-isoLD1 have been identified as tumor-associated antigens whose formation is initiated by the Lc3-synthase. Until now, high-affinity IgG monoclonal antibodies (mAbs) against 3′-isoLM1 and 3′,6′-isoLD1, which are highly expressed in gliomas, have not been developed, although mAbs against lacto-series gangliosides are powerful tools for functional studies. We previously produced the Lc3-synthase gene β3Gn-T5 knockout mice. In this study, we immunized β3Gn-T5 knockout mice with 3′-isoLM1/3′,6′-isoLD1 and produced the anti-3′-isoLM1/3′,6′-isoLD1 mAb GMab-1, of the IgG₃ subclass, which should be useful for functional analysis of lacto-series gangliosides and for antibody-based therapy of gliomas.