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SPECIALITY

A stealthy way to

combat tumors

Biologists show that helper immune cells disguised as cancer cells can help
rejuvenate T cells that attack tumors

nder the right circumstances,
the body’s T cells can detect
Uand destroy cancer cells.
However, in most cancer patients,
T cells become disarmed once they
enter the environment surrounding
a tumor.
Scientists are now trying to find
ways to help treat patients by
jumpstarting those lackluster
T cells. Much of the research
in this field, known as cancer
immunotherapy, has focused on
finding ways to stimulate those T
cells directly. MIT researchers have
now uncovered a possible new way
to indirectly activate those T cells, Image source: news.mit.edu
by recruiting a population of helper
immune cells called dendritic cells.
help to enhance the effectiveness Dendritic cells are known to help
In a new study, the researchers of cancer immunotherapy, she says. activate tumor-fighting T cells, but
identified a specific subset of In a study of mice, the researchers there are many different subtypes of
dendritic cells that have a unique showed that stimulating these dendritic cells, and their individual
way of activating T cells. These dendritic cells slowed the growth of roles in T cell activation are not fully
dendritic cells can cloak themselves melanoma and colon tumors. characterized. In this study, the MIT
in tumor proteins, allowing them team wanted to investigate which
to impersonate cancer cells and Spranger is the senior author of the types of dendritic cells are involved
trigger a strong T cell response. study, which appears today in the in T cell responses that successfully
journal Immunity. The lead author of eliminate tumors.
“We knew that dendritic cells the paper is MIT graduate student
are incredibly important for the Ellen Duong. To do that, they found a tumor
antitumor immune response, but we cell line, from a type of muscle
didn’t know what really constitutes Spontaneous regression tumor, that has been shown to
the optimal dendritic cell response spontaneously regress in mice.
to a tumor,” says Stefani Spranger, When tumors begin to form, they Such cell lines are difficult to find
the Howard S. and Linda B. Stern produce cancerous proteins that because researchers usually don’t
Career Development Professor at T cells recognize as foreign. keep them around if they can’t form
MIT and a member of MIT’s Koch This sometimes allows T cells to tumors, Spranger says.
Institute for Integrative Cancer eliminate tumors before they get
Research. very large. In other cases, tumors Studying mice, they compared
are able to secrete chemical signals tumors produced by that regressive
The results suggest that finding that deactivate T cells, allowing
ways to stimulate that specific the tumors to continue growing 8
population of dendritic cells could unchecked.

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