According to a recent study conducted by the researchers at Uppsala University in Sweden have discovered lymph node-like structures close to the tumour in brain cancer patients where immune cells can be activated to attack the tumour.
The study has been published in the journal Nature Communications where the researchers found that immunotherapy improved the formation of these structures in a mouse model. New opportunities have been suggested in this discovery to regulate the anti-tumour response of the immune system.
Glioma is a deadly brain tumour with a dismal prognosis. Due to our immune system which is designed to detect and destroy foreign cells including cancer cells that cannot easily reach the tumour site due to the barriers that surround the brain and this is one of the reasons why brain tumours are very hard to treat.
The discovery of structures similar to lymph nodes in the brain where T lymphocytes could be activated described the researchers.
To fight a developing tumour, killer immune cells such as T lymphocytes must be activated and primed in our lymph nodes, before travelling to the tumour site to effectively kill the cancer cells. It is a challenging process for T lymphocytes to reach the tumour because of the barriers around the brain.
Alessandra Vaccaro, PhD student at the Department of Immunology, Genetics and Pathology said, “It was extremely exciting to discover for the first time the presence of lymph node-like structures in glioma patients. These structures are known as tertiary lymphoid structures (TLS) and they are not found in healthy individuals. They have all the components needed to support lymphocyte activation on-site which means that they could have a positive effect on the anti-tumour immune response.”
The formation of TLS in the brain can be induced by a type of immunotherapy in glioma-bearing mice were shown by the researchers. Indeed, when they treated the mice with immunostimulatory antibodies called aCD40, the formation of TLS was enhanced and always occurred in proximity to tumours.
“Learning that immunotherapies can modulate the formation of tertiary lymphoid structures in the brain offers exciting opportunities to find new ways of regulating the anti-tumour immune response in glioma,” said Anna Dimberg.
aCD40 is now being tested to treat brain tumours in a number of clinical trials. The study has therefore provided important insights into the multifaceted effects of aCD40 therapy.The researchers found in the study that while aCD40 boosted TLS formation, it also counterproductively inhibited the tumour-killing ability of the T lymphocytes.