The adaptive immune system is the subsystem of an entire immune system. Characteristically, the adaptive immune system is comprised highly systematic and specialized cells and processes whose main purposes are to eliminate or inhibit the growth of pathogens within specific hosts. The adaptive immune system is infamous for its ability to place the body in better states to fight similar pathogens in subsequent infections. Nonetheless, both the cell-meditated and humoral immunity of the adaptive immune systems lacks the desirable ability to distinguish between harmful and harmless invading pathogens.
Primary Cell Type
Lymphocytes are the primary cell type in the composition of the adaptive immune systems. Specifically, the T cells and the B cells are the major sub-set lymphocytes that are critical to the activities of the entire adaptive immune system. Lymphocytes in the adaptive immune system are morphologically similar to each other until after their activation and are derived from multipotent hematopoietic stem cells. Together, both the sub-sets of B cells and the T cells are intimately involved in humoral immune responses as well as cell-meditated immune responses. With the exclusion of agnatha, all the vertebrates derive their lymphocytes from the bone marrow. Notably still, lymphocytes move within the lymphatic systems and the tissues with only less than 2% of its total volume let out in the peripheral blood circulation units.
Impacts of the Ageing Process on the Lymphocytes
Predictably, lymphocytes, just like other body systems are susceptible to regression due to ageing. Regression of the thymus due to age subsequently leads to a decline in the output of the lymphocytes; most often the output of the T cells. Underproduction of lymphocytic components triggers an increased susceptibility to infections as witnessed in numerous ageing individuals.
Work Cited
Janeway, Charles A, Paul, Travers, MJ. Walport, andMark, Schlomchik J. Immunobiology: Immune System in Health and Disease. Edinburg: Churchill Livingstone, 2001. Internet Resource
