Vaccine Derived from Cancer Stem Cells Induces Strong Antitumor Effect

A novel vaccine based on antibodies developed in mice that had been immunized with a preparation of concentrated cancer stem cells (CSCs) was found to be capable of targeting CSCs in vivo and of conferring antitumor immunity.

Investigators at the University of Michigan (Ann Arbor, USA) examined the vaccination effects produced by CSC-enriched populations from histologically distinct mouse tumors after their inoculation into different, but genetically identical immunocompetent hosts.

Results published in the April 1, 2012, issue of the journal Cancer Research revealed that enriched CSCs were immunogenic and more effective as an antigen source than unselected tumor cells in inducing protective antitumor immunity. Immune sera from CSC-vaccinated hosts contained high levels of IgG, which bound to CSCs, resulting in CSC lysis in the presence of complement. Cytotoxic T lymphocytes (CTLs) generated from peripheral blood mononuclear cells or splenocytes harvested from CSC-vaccinated hosts were capable of killing CSCs in vitro.

“This is a major breakthrough in immunotherapy research because we were able to use purified cancer stem cells to generate a vaccine, which strengthened the potency of antibodies and T cells that selectively targeted cancer stem cells,” said senior author Dr. Qiao Li, research assistant professor of surgery at the University of Michigan. “We found that these enriched cancer stem cells were immunogenic and far more effective as an antigen source compared with the unselected tumor cells normally used in previous immunotherapy trials. The mechanistic investigations found that when antibodies were primed with cancer stem cells, they were capable of targeting cancer stem cells and conferring antitumor immunity.”

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