 Involves specificity & memory, increases effectiveness with each exposure to an antigen  Antigens: Substances that stiumulate adaptive immunity responses  2 types of Antigens  Foreign Antigens: From outside the body— bacteria, viruses, chemicals, foreign cells Allergies, Allergic reactions  Self-antigens  Molecules produced by a person’s body—tumors Autoimmune diseases Can be harmful attacking itself Rheumatoid arthritis

 Lymphocytes: (2) B-Cells & T-Cells  B-Cells produce antibodies found in plasma— antibody-mediated immunity  Released from red bone marrow  T-Cells produce cell-mediated immunity  Released from the thymus (several subpopulations of T Cells)  Both circulate through blood and lymph  5 T-cells for every 1 B-Cell, divide when stimulated for an immune response.

 B & T cells make clones that can react to different antigens (specificity)  Adaptive immune responses occur  Antigen recognition by lymphocytes  Proliferation of lymphocytes recognizing an antigen  Lymphocytes have antigen-binding receptors on their surfaces that activate the immune response

 B & T cells usually respond to antigen fragments presented by macrophages  Major histocompatibility complex (MHC) are molecules that hold antigens on the plasma membrane of macrophages--first signal to produce a response from B or T cells  Costimulation is a second signal by cytokines, regulates neighboring cells that also stimulates an immune response  Costimulation causes T cells to divide and the number greatly increases for a proper response

 Antigen recognition causes B cells to produce antibodies  Antibodies will bind to antigens and destroy them in multiple ways  Antibodies are found in body fluids to attack bacteria, viruses & toxins  Antibodies are a type of globulin plasma protein  Y in shape with a variable region that would bind to a specific antigen  Effect antigens directly or indirectly

 Direct effects of antibodies occur when a single antibody binds with an antigen or antigens-- agglutination of RBCs  Used to determine if immunity is present  Indirect effects happen when an antibody binds to an antigen and the constant region activates complement or allows macrophages to attach and phagocytize the cell  Stimulates inflammation, WBCs, chemotaxis & lyses

 Primary response: results from the first exposure of B cells to antigens  B cells form plasma cells (produce antibodies) & memory B cells  Primary response takes 3-14 days  Person develops disease symptoms due to antigen causing tissue damage

 Secondary or Memory Response: Primary response of immune system has already occurred, memory B cells quickly divide forming plasma cells that produce antibodies to attack the antigen  Time to produce antibodies is much less  More antibodies are produced  Antigen is quickly destroyed and no disease symptoms develop--person is immune  Additional memory B cells are produced

 Cell mediated immunity is most effective against microorganisms using T cells  Cytotoxic T cells: attach to MHC complex  Helper T cells: divide and activate other cells  Memory T cells: create the secondary response for long lasting immunity  Two effects of cytotoxic T cells  Release cytokines attract macrophages & more T cells  Bind to antigens on viral, tumor or foreign antigens (transplant) cause the cells to be ruptured

 Immunotherapy: treats diseases by altering immune system function or attacking harmful cells  Boost the immune system with cytokines trigger inflammation  Inhibiting the immune system  Vaccination  Radioactive isotopes, drugs, toxins, enzymes  The use of monoclonal antibodies to treat tumors is mostly in research stage of development.

 4 ways to develop adaptive immunity  Active natural  Active artificial  Passive natural  Passive artificial  “Natural” contact with antigen was not deliberate  “Artificial” means contact was deliberate  “Active” exposure is responded to by individual’s own immune system  “Passive” immunity is transferred from one organism to another

 Active Natural: person is exposed, immune system reacts, usually develops symptoms  Active Artificial: Antigen deliberately introduced to stimulate response  Active Artificial is known as vaccination  Vaccines use part of a microorganism, dead microorganism or live altered microorganism to cause immune response

 Passive Natural: transfer of antibodies from mother to child across the placenta or nursing  Mother’s antibodies protect the child for the first few months, eventually broken down and child’s immune system must take over  Passive Artificial: organism is vaccinated, antibodies are removed and administered to another organism, antiserum for venoms  Temporary immunity