Protein serves as a natural boost for immune system fight against tumors

Substances called adjuvants that enhance the body's immune response are critical to getting the most out of vaccines. These boosters stimulate the regular production of antibodies—caused by foreign substances in the body—toxins, bacteria, foreign blood cells, and the cells of transplanted organs.

But, biologists think that adjuvants could be much better: The currently available licensed adjuvants are poor inducers of T and even worse at inciting killer T that clear viruses, as well as eradicate cancer cells.

The lab of David Weiner, PhD, professor of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, identifies new adjuvants that can produce the desired T-cell response. "Different molecular adjuvants, such as cytokines, are being studied as a way to increase the efficacy of vaccines," explains Weiner. "The development of DNA-based vaccines with cytokine adjuvants has emerged as particularly promising for inducing antiviral and anti-tumor, cell-mediated immune responses."

Daniel Villarreal, a graduate student in the Weiner lab, and colleagues report in Cancer Research this week that the protein IL-33 boosts the immune system of a human papilloma virus of cancer. IL-33 is a cytokine, a small protein that signals such as T cells to travel to a site of infection or injury.

Although still experimental, DNA vaccines are a conceptual leap forward over standard vaccines, as they are not live and never expose the person being vaccinated to a true pathogen or infectious agent. They are transient and do their job by fooling the host's immune system into believing there is an infectious agent invading their cells so that the host responds by producing protective levels of T cells, in particular CD8 killer T cells. DNA vaccines have been studied in animal models of viral, bacterial, and parasitic disease, as well as animal models of tumors. Due to major advances in their immune potency DNA vaccines are being studied in human clinical trials for treating cancer and infectious diseases.

The team showed that IL-33 can further enhance the response of memory T cells, the long-lived cells that can patrol and protect the body from infections and cancers, when given with a DNA vaccine compared to a vaccine without IL-33. What's more, IL-33 and the DNA vaccine augmented immunological responses in both CD4 helper T cells and CD8 killer T cells, with a large proportion of CD8 killer T cells demonstrating a further improvement in the ability of DNA vaccines to drive the to kill tumor cells in animals.

"Our results support the further study and possible development of IL-33 as adjuvants in vaccinations against pathogens, including in the context of antitumor immunotherapy," says Weiner. Additional cancer and infectious diseases studies in diverse animal models are in progress.

add to favorites email to friend print save as pdf

Related Stories

Explainer: What is the immune system?

Jan 08, 2014

The immune system is an integral part of our body, keeping us safe from diseases – from the common cold to more severe illnesses such as cancer.

Vaccine adjuvant uses host DNA to boost pathogen recognition

Apr 05, 2013

Aluminum salts, or alum, have been injected into billions of people as an adjuvant to make vaccines more effective. No one knows, however, how they boost the immune response. In the March 19, 2013, issue of the Proceedings of ...

Adjuvant combo shows potential for universal influenza vaccine

Jun 08, 2011

Researchers at National Jewish Health have discovered how to prime a second arm of the immune system to potentially boost influenza vaccine effectiveness. A combination of two adjuvants, chemicals used to boost the effectiveness ...

Recommended for you

Unraveling the 'black ribbon' around lung cancer

Apr 17, 2014

It's not uncommon these days to find a colored ribbon representing a disease. A pink ribbon is well known to signify breast cancer. But what color ribbon does one think of with lung cancer?

User comments