Cancer vaccine could be in the pipeline

May 25 2008

Cancer researchers in the UK say they are one step closer to producing a specific targeted vaccine for killing cancer cells.

The researchers have pinpointed a protein on immune cells which they hope will help them harness the body's defences to attack a tumour.

They say the protein is unique to a type of immune cell called a dendritic cell which is responsible for triggering the body's defence system and a vaccine designed to "home in" on the protein would deliver a message to the immune system to attack the invading cancer.

The team at the UK Cancer Research London's Institute say scientists have been searching for proteins or "tags" on dendritic cells for over 30 years - dendritic cells were first discovered in 1973.

This is because they believe a vaccine carrying a foreign molecule from a cancer cell could be targeted to the dendritic cells, which would then prompt the immune system to attack the "invading" cancer and explains why finding a unique tag on dendritic cells was such an important project.

They say the results of their research are an important step towards understanding how to create targeted cancer vaccines in the future.

The role of the dendritic cell is to present pathogens or foreign molecules to other cells of the immune system, which in turn eliminate them.

So in theory a vaccine carrying a foreign molecule from a cancer cell could be targeted to the dendritic cells, which would then prompt the immune system to attack the "invading" cancer.

The researchers say the same approach could be used for treating HIV or malaria.

According to the study leader Dr. Caetano Reis e Sousa, the team discovered a unique protein called DNGR-1, which could be used to deliver such a vaccine to the dendritic cell.

Dr. Reis e Sousa says vaccines work by triggering an army of immune cells, called T cells, to attack potentially dangerous foreign molecules, like those found on pathogens, and dendritic cells are the messengers, telling the T cells who to attack.

Dr. Reis e Sousa says the vaccines will carry a sample of the offending molecule and deliver it to DNGR-1 on the dendritic cells, which in turn will present the molecule to the armies of T cells and instruct them to attack.

Dr. Lesley Walker, director of cancer information for Cancer Research UK, says developing treatments that accurately target cancer and have few serious side-effects is one of Cancer Research UK's top goals and the results of the research are an important step towards understanding how to create targeted cancer vaccines in the future.

There are two main types of cancer vaccines, vaccines to prevent cancer and vaccines to treat cancer - dendritic cell vaccines treat cancer and vaccine therapy is one of the most exciting areas of cancer research.

Such research is currently at an early stage and to date, only a very small number of people have benefited from vaccines - most vaccine therapy research has been as a treatment for melanoma because of the lack of successful treatments for advanced melanoma.

The research is published in the Journal of Clinical Investigation.