Revolutionary immune research: New findings about T cells discovered!

Revolutionary immune research: New findings about T cells discovered!

A new study by the Max Planck Research Group for Systems Immunology at the University of Würzburg has published remarkable findings about the immune response. The results could have significant implications for vaccination strategies and cellular immunotherapies. The team led by Wolfgang Kastenmüller and Georg Gasteiger discovered that the T cells – central defense cells of the immune system – are activated in a previously unknown phase that is crucial for the targeted fight against pathogens. These findings were published on April 11, 2025 in the journal *Science*.

T cells play an indispensable role in the immune system as they must proliferate and specialize in order to effectively destroy infected cells. T cell priming begins when T cells encounter dendritic cells (DCs) in the lymph nodes. These present antigens and activate the T cells. During this activation, which lasts about 24 hours, the T cells remain in contact with the DCs and receive crucial instructions. After activation, the T cells continue to migrate, multiply and develop into either effector cells or memory cells.

The phases of T cell activation

The study shows that the process of T cell activation consists of two clear phases. In the first phase, many specific T cells are activated, while in the second phase, those T cells that recognize the pathogen most effectively are selected and expanded. This finding could provide the basis for improving immunotherapies, particularly in the treatment of cancer.

Chronic infections and cancers show similar phases of activation and even desensitization of the immune response. CAR T cells are currently used in various therapies to combat cancer cells. The innovations from the Würzburg research work could enable important progress here.

The adaptive immune response is usually activated when innate immunity fails. Sensor cells of innate immunity are crucial to trigger the adaptive immune response by recognizing antigens. In most cases, the innate defense mechanisms are not sufficient, which is why an activated adaptive immune response is necessary to successfully fight the infection. It is expected that the new insights into how naïve T cells recognize and differentiate their specific antigens could promote the development of future therapies.

The mechanism of T cell activation

Naïve T cells circulate through blood and lymphoid tissue to recognize potential antigens. These require specific antigens in the form of peptide:MHC complexes to be activated. The process is complex and requires both antigen presentation and costimulatory signals. Dendritic cells, which are considered the most important antigen-presenting cells, are emblematic of this activation mechanism. Activated dendritic cells not only present antigens but also express costimulatory molecules that are essential for T cell activation.

In addition, secondary lymphatic organs such as lymph nodes and spleen are crucial for the adaptive immune response. Chemokines direct T and B cells to specific zones within these organs to ensure an effective response to pathogens. T effector cells, which arise from activated naïve T cells, display altered surface molecules and are able to respond rapidly to target cells by killing infected cells and releasing immunomodulators.

These new findings provide broad context for our understanding of immune responses, particularly in relation to the development of sustainable vaccination strategies. Vaccinations aim to exploit the principle of immunological memory by preparing the organism for new encounters with pathogens, thus enabling faster protection. Ongoing research could revolutionize the immunotherapy paradigm and reveal new ways to combat disease. University of Würzburg reports that..., PMC notes that…, and According to PMC it shows that...