Final answer:
Lymphocytes are white blood cells that are key to the adaptive immune response, with B cells producing antibodies and T cells attacking infected cells. They also include NK cells of the innate immune system and can form a memory for quicker response upon re-exposure to pathogens.
Step-by-step explanation:
Lymphocytes are a specialized type of white blood cell that play a crucial role in the body's adaptive immune response. These cells come in different forms, such as B cells and T cells, each with specific functions within the immune system. B cells are responsible for producing antibodies that can recognize and bind to specific antigens, leading to the removal of pathogens. T cells, on the other hand, may directly destroy infected cells or aid in modulating the immune response. A subset of lymphocytes known as natural killer (NK) cells are part of the innate immune system and can kill cells infected with viruses or those that are cancerous.
Lymphocytes account for about a quarter of all white blood cells in the human body and are primarily found in lymphatic tissues such as the lymph nodes, spleen, and tonsils. They circulate in the blood but are more abundant in the lymphatic system. These cells can develop a memory of pathogens, which enables a faster and more effective immune response upon re-exposure to the same pathogen.