IgM is the most evolutionary conserved antibody isotype that presents in all vertebrates, which is also the earliest isotype expressed during immune development. IgM is known to be the first line of defense against various antigens which is mainly responsible for recognizing and eliminating infectious particles as well as removing transformed cells. In the field of tumor biology, native IgM has a direct cytotoxic effect on tumor cells mainly by recognizing tumor-modified cell surfaces that develop during tumorigenesis and activating complement system to destroy nascent transformed cells. In addition, IgM antibodies can target some cancer cell markers more efficiently than IgG class antibodies with higher avidity. Screening antibodies isolated from cancer patients revealed that almost all of the identified tumor-specific antibodies belong to the IgM class. And these isolated tumor-specific IgM antibodies have been shown to induce tumor cells apoptosis, suggesting that IgM antibody can be used as a therapeutic antibody for the treatment of cancers.
Learn more: IgM Antibody Targets Tumors