Researchers from the Okayama University have developed a group of immune cells that can infiltrate tumors and deliver viral vectors, destroying them from the inside out. The team’s work was published in the journal Scientific Reports.

The team developed the tumor-targeting technique using a human T-cell line known as HOZOT, which naturally targets human cancer cells. HOZOT cell lines are established by co-cultivating human umbilical cord blood cells and mouse stromal cells, according to the researchers. The HOZOT cells are toxic to tumors, but do not target healthy tissue.

The scientists hypothesized that the HOZOT cells could be used to carry an adenovirus that kills the tumor from the inside. They conducted trials with the targeted therapy against a variety of human cancer cells, including colon cancer, and found that the HOZOT carriers significantly reduced the viability of human cancer cells.

Additional trials in mice showed increased survival rates in those treated with the immune cells. The team noted that the HOZOT carriers appeared to stop the immune system from reacting to the adenovirus.

Many cancer patients have developed a degree of immunity to viral vectors, because cancer treatments have already been developed using viral-based drugs that target harmful tumor tissue. However, because the virus is protected by the HOZOT cells, the host’s immune system is not triggered to release neutralizing antibodies to target the virus.

“The unique cell-in-cell property of virus-loaded HOZOT cells provides a platform for selective delivery of biologics into human cancer cells, an outcome that has important implications for the treatment of human cancers,” the team wrote.