The immune system primarily consists of which types of cells?

The immune system is fundamentally composed of various types of white blood cells, which play crucial roles in defending the body against pathogens. T cells and B cells are two of the primary components of the adaptive immune response.

T cells, including helper T cells and cytotoxic T cells, are vital for identifying and responding to infected or malignant cells. They help regulate the immune response and directly attack infected cells. B cells, on the other hand, are responsible for producing antibodies, which are proteins that specifically target and neutralize pathogens such as viruses and bacteria. This antibody production is a critical function in the immune response that provides long-term immunity.

While neutrophils and macrophages are also important immune cells that contribute to the innate immune response, they do not fulfill the same specific roles as T and B cells in adaptive immunity. Red blood cells and platelets are crucial for oxygen transport and blood clotting, respectively, but they are not involved in immune defense. Similarly, pancreatic cells and liver cells function in metabolism and digestion, rather than in immune processes. Therefore, T cells and B cells are rightly recognized as central to the immune system's function.