Final answer:
T cells, or T lymphocytes, are the lymphocytes that are primarily in charge of cellular immunity, attacking infected or abnormal cells directly. While B cells also belong to the lymphocyte family, they are responsible for humoral immunity, producing antibodies against pathogens. NK cells also contribute to the defense against infections and tumors but are part of the innate immune system.
Step-by-step explanation:
Lymphocytes and Cellular Immunity
The lymphocytes responsible for cellular immunity are known as T cells or T lymphocytes. T cells are a type of white blood cell that plays a critical role in the adaptive immune system. They actively participate in the body's defense against pathogens by directly attacking infected cells or abnormal cells, such as those that are cancerous. These cells are particularly effective against viral infections and also play a role in defending against fungi, parasites, and some bacteria.
T cells mature in the thymus gland, which contributes to their name. There are different types of T cells, each with unique functions in the immune response. For example, cytotoxic T cells (CD8+ T cells) kill infected cells, whereas helper T cells (CD4+ T cells) assist other cells in the immune system with their functions.
B cells, or B lymphocytes, are also a critical component of the adaptive immune system by providing humoral immunity through the production of antibodies that bind to specific antigens. However, they are not primarily involved in cellular immunity but are more responsible for producing antibodies in response to pathogens, which is known as humoral immunity.
Another type of lymphocyte involved in the immune response is the natural killer (NK) cell which plays a role in controlling various types of infections and tumors by directly attacking those cells that do not properly display MHC I molecules. While these cells are part of the innate immune system, they share some characteristics with T cells.