Weizmann team finds immune memory cells that recognise ovarian tumours

Researchers at the Weizmann Institute of Science in Rehovot reported on 26 May 2026 that memory B cells, the immune cells that let the body respond quickly to a virus or bacterium it has met before, can also recognise ovarian cancer. The study, published in the journal Immunity, was carried out in the laboratory of Prof. Ziv Shulman in the Department of Systems Immunology and was led by Dr. Nachum Nathan, working with surgeons and pathologists at Rabin Medical Center.

The team examined tumour tissue and nearby lymph nodes from 11 women with high-grade serous ovarian cancer, the most common form of the disease. In the lymph nodes they found memory B cells whose genes encoded antibodies aimed at the tumour, even though no active immune attack was under way. When the scientists produced those antibodies in the laboratory, more than a third of them bound strongly to ovarian cancer cells and much less to healthy cells. Some targeted a protein that helps the cancer spread, which the tumour may find hard to change without harming itself.

The researchers also looked at why these cells stay quiet. They found that scavenger cells called macrophages in the lymph nodes suppress the formation of germinal centres, the structures where B cells are normally switched on and refined. That suggests a possible point of intervention: if the brake can be released, the body's existing memory against the tumour might be put to work.

Until now, memory B cells were generally thought to respond mainly to outside invaders. Showing that patients already carry a reservoir of tumour-recognising memory cells opens a new line of research for immunotherapy, alongside the T-cell approaches that dominate the field today. The work was covered by the Times of Israel and reprinted in Jewish community papers abroad as a world first.