Washington, May 28:Scientists
claim to have engineered a protein which allows the body`s immune cells
to get inside tumours and attack cancer cells.
The pioneering experiment, published in the `Proceedings of the
National Academy of Sciences` journal, was carried out by an
international team led by Prof Ruth Ganss at the Western Australian
Institute for Medical Research.
"Until now, immunotherapy has not been very successful in treating
cancer because tumours are very resistant to immune cells," said Dr Anna
Johansson, from The University of Western Australia, a team member.
"As a cancerous tumour grows, it forms a solid ball which is
difficult for immune cells to get into and even if they can penetrate
the tumour, the environment inside it either kills the cells or makes it
difficult for them to function.
"We engineered a protein called TNF-Alpha so that it went straight to
a pancreatic tumour and stayed there without toxic side effects outside
the tumour. TNF-Alpha affected the blood vessels in the tumour in a
surprising way which opened the solid ball so that immune cells could
get inside.
"We thought it might damage the blood vessels because TNF-Alpha can
be very toxic, but in low doses it actually improved them and increased
healthy blood flow, helping immune cells to get inside the cancer," she
said in a release.
TNF-Alpha has been shown to enhance the tumour`s response to
chemotherapy but until now researchers did not understand why. This
study provides insights on how low-dose TNF-Alpha works in tumour and
also shows for the first time that it can be combined with
immunotherapy.