Lenfositler (lymphocytes) are a type of white blood cell that play a crucial role in the immune system. They help the body fight infections and diseases by identifying and attacking harmful pathogens, such as bacteria and viruses. There are three main types of lymphocytes: T hücreleri (T cells), B hücreleri (B cells), and natural killer hücreleri (natural killer cells), each with specific functions in immune response. Lymphocytes are produced in the bone marrow and mature in different parts of the body, including the thymus for T cells and the spleen for B cells. When the body encounters an infection, lymphocytes are activated and multiply to help eliminate the threat. Their ability to remember past infections also allows for a quicker response to future attacks by the same pathogen.