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Immunology and Cancer

Jianzhu Chen: June 8, 2006; Running Time: 59:46

About the Lecture

About the Lecture

Jianzhu Chen lays out the thorny challenges of harnessing the immune system to fight cancer. He starts with the basics: how the body employs two levels of defense against pathogens: native and adaptive immunity. The latter type of protection specifically interests Chen, because it can recognize and remember “an almost unending number” of specific pathogens, both inside and outside cells.

B cells, produced in the bone marrow, can generate antibodies for clearing out bacteria, and T cells, originating in the thymus, go after viruses and other intracellular threats. They work by identifying an antigen (foreign substance) and expressing receptors -- cell surface proteins -- that bind to those antigens.

Early on, the immune system learns to distinguish between what is self and what is a pathogen. It develops, says Chen, “layers of self-tolerance,” without which the body might launch an assault on itself. But cancers can manipulate this useful feature of the immune system. Some tumors express chemicals, or summon naturally occurring suppressor cells in order to prevent T-cells from attacking them. So, says Chen, to mount an immune response against cancer, says Chen, you “need to induce a response against the self—you have to overcome the built-in tolerance mechanism of the immune system.”

Chen sees evidence of the possibility of overcoming “tumor-induced tolerance.” For instance, some tumors spontaneously shrink, and there’s an accumulation of immune cells at tumor sites. Researchers are focusing on three areas: using antibodies or T cells in cancer therapy; developing a therapeutic vaccine that would induce cancer specific antibodies or T-cells; and designing a vaccine to prevent cancer that would induce the memory of B or T cells for a specific cancer. Much hard work remains: identifying tumor associated antigens, most of which, says Chen, the body sees as “normal self proteins;” and then coming up with T or B cells specifically targeting these tumor associated antigens.

Lecture Details

Location: 46-3002

“Someday we should be able to harness the power of T cells to directly kill tumor cells, but we need a better understanding of T cell-tumor interaction, how to overcome self-tolerance mechanisms, and tumor induced tolerance too. ”

Jianzhu Chen

About the Speaker

Jianzhu Chen

Cottrell Professor of Biology;
Professor of Immunology

Jianzhu Chen is also an adjunct professor and co-director of the Center for Infection and Immunity, the Chinese Academy of Sciences. He received a Ph.D. in Genetics from Stanford University and was an instructor at Harvard Medical School before joining the faculty at MIT.

The Chen lab is interested in understanding immune response and memory to respiratory virus infection at molecular, cellular, and organismal levels. The lab uses influenza virus infection in mice as a model system. Researchers follow immune cell responses to the virus during the entire course of infection, their subsequent development into memory lymphocytes, and the effect of specific gene mutation on the processes. Chen's lab is also using new molecular technologies to develop therapies that could be relevant for other infectious respiratory diseases such as SARS.