Israeli Researchers Find "Immune-Memory" B Lymphocytes in Ovarian Cancer Patients
According to Xinhua, the Weizmann Institute of Science in Israel recently issued a statement saying that researchers analyzed tumor samples from 11 patients with high-grade serous ovarian cancer (one of the most common and aggressive types of ovarian cancer) as well as immune cells in nearby lymph nodes. They found B cells bearing immune memory in these lymph nodes, carrying genetic information for antibodies that recognize the tumor. The relevant paper has been published in the American academic journal Immunity. The discovery offers new ideas for developing cancer immunotherapies and preventing cancer recurrence.
Experiments showed that more than one-third of the antibodies produced by these B cells bound strongly to ovarian cancer cells but weakly to the body's own healthy cells, indicating strong targeting.
The study found that these memory B cells may persist long-term in lymph nodes near the tumor, though they do not show an active immune response within the node. When needed, they can migrate from the lymph node to the tumor site and become activated, thereby continuously participating in the immune response against the cancer.
The study also showed that the antibodies produced by some of these memory B cells target key proteins on which ovarian cancer spread depends. Because cancer cells cannot easily shed these key proteins through mutation, the corresponding antibodies may provide long-term immune protection.
As to why the immune-memory B cells are not activated in the lymph nodes, the study confirmed that macrophages suppress the activation of B cells within the nodes.
For most ovarian cancer patients, existing immunotherapies are generally not very effective. The researchers say this new discovery may offer a new direction for improving related treatment.
The study points out that the human body may possess the ability to form long-term immune memory against cancer. Not only may this enable the development of new cancer immunotherapies, it may also help extend cancer immunotherapy from treatment into the prevention of recurrence. In future, if the activity of these B cells can be regulated, it might also be used to suppress overactive immune responses in autoimmune diseases.
Note: Ovarian cancer is a gynecologic tumor that is very hard to treat; current treatments such as bevacizumab, PD-1, PD-L1, and CAR-T are not very effective against it. This new study from the Weizmann Institute may open a new direction for ovarian cancer immunotherapy, but it is still a long way from clinical practice.