Table of ContentsAdaptive Immune SystemLymphocytes: Lymphocytes BLymphocytes TAdaptive Immune SystemThis system can recognize and eliminate specific foreign microbes and molecules that enter the body. The adaptive immune system has four characteristics. Say no to plagiarism. Get a tailor-made essay on “Why violent video games should not be banned”? Get the original essay Antigen specificity Diversity Immunological memory Self and non-self recognition Antigen specificity of the immune system distinguishes between differences between antigens. Antibodies can differentiate two protein molecules that differ by only a single amino acid. The immune system is capable of generating diversity in its recognition molecules. This ability contributes to the recognition of the shapes of molecules of the innate system. Once the immune system has recognized and responded to an antigen, it exhibits immunological memory and then, for the second time, it induces a state of heightened reactivity. Thanks to this property, the immune system can provide lifelong immunity against many infections after the first encounter. The immune system responds only to foreign antigens, indicating that it is capable of recognizing self-non-self. Lymphocytes: Cells of the adaptive immune system are special types of leukocytes called lymphocytes. B cells and T cells make up the main type of lymphocytes. They are derived from hematopoietic stem cells in the bone marrow. Both lymphocytes contain receptor molecules that recognize a specific antigen. Lymphocytes leave the bone marrow after maturation and circulate in the bloodstream and lymphoid organs because they contain receptors. B Lymphocytes B lymphocytes mature in the bone marrow and, upon release, present antigen receptors on their membrane. Antigen receptors are a membrane-bound antibody molecule. These antibodies are glycoproteins made up of two identical polypeptides. When the antigen matches the antibody on the membrane, it results in division and the progeny differentiate into memory B cells and effector B cells called plasma cells. Memory B cells have a longer lifespan than naive cells; they also express antibodies similar to those of their parent B cell. In plasma cells, they produce antibodies as a secretion that does not contain any membrane-bound antibodies. The lifespan of plasma cells is a few days and they secrete more antibodies during this period. These secreted antibody molecules are major effectors of humoral immunity. T Lymphocytes T lymphocytes also appear in the bone marrow, but migrate to the thymus region for maturation. These mature T cells display a unique antigen-binding molecule, namely the T cell receptor on its membrane. T cells are subdivided into T helper cells (TH) and cytotoxic T cells (TC). These two elements can be differentiated from each other based on the presence of membrane glycoproteins CD8 or CD4. Keep in mind: this is just a sample. Get a personalized article from our expert writers now. Get a custom assay on T cells that exhibit CD4 functions as T helper cells and those that exhibit CD8 are cytotoxic T cells. Most of the time, T cell receptors can only recognize antigen bound to a cell membrane protein called major histocompatibility complex (MHC) molecules...