The flaws of the immune system
Our immune system protects us from infections and harmful cells. It has two main parts. The innate immune system acts fast and forms the first barrier, using the skin and certain cells that immediately attack invaders. The adaptive immune system responds more slowly but is highly specific. Its T and B cells learn to recognize a particular threat and remember it, allowing faster responses in the future.Although the immune system is usually well‑regulated, it can make mistakes. Sometimes immune cells attack the body’s own tissues, causing autoimmune diseases. In other cases, the system’s signalling molecules — cytokines — become unbalanced, contributing to conditions such as infections, sepsis, and cancer.This thesis explores two examples of such failures.First, we study ANCA‑associated vasculitis, an autoimmune disease in which certain B cells escape removal and start attacking the body. We show how the bacterium Staphylococcus aureus may help trigger this loss of immune tolerance through two different mechanisms.Next, we examine GOLM1, a protein that influences how many cytokines immune cells produce. Changes in GOLM1 levels can disturb the immune balance and affect susceptibility to infections and inflammatory diseases.Finally, we introduce ProliSpot, a new method that can detect extremely rare dividing cells. This allows researchers to measure immune responses with much greater sensitivity than existing techniques.