Immunity Chapter 40 Section 2

Lymphatic System

Types of White Blood Cells Formed in Bone Marrow, Thymus, spleen, and / or lymph system –Lymphocytes (B and T Cells) –Monocytes –Neutrophils –Basophils: secret histamines –Eosinophils

White Blood Cells Neutrophils –phagocytic cells –Damaged cells release chemicals that neutrophils recognize (chemotaxis) –Use phagocytosis to destroy invading cells –Life span: few days

White Blood Cells Macrophages (Monocytes) –Largest phagocytic cells –Effective and long – lived –Engulfs invading cell and merges it with a lysosome. Needs helper T cells. –Some migrate and others are fixed.

Other White Blood Cells Eosinophils –Attacks larger parasitic invaders –Limited phagocytic activity –Attack by sending destructive enzymes to the cell wall of invader.

NK Cells Natural Killer Cells –Not phagocytic –Destroys virus infected cells and abnormal body cells –Causes cells to lyse by breaking down the membrane.

Antimicrobrial Proteins 20 serum protiens known as compliment system Leads to lysis of microbes Other protiens include interferons: Inhibit viruses from invading neighboring cells interupting replication (above 2 interferons)

The Inflammatory Response Localized Triggered by tissue damage Blood supply to area increases Chemical signals are released

The Inflammatory Response Basophils and mast cells secret histamine Prostaglandins released Neutrophils, then Macrophages arrive

The Inflammatory Response

Self VS. Nonself Immune system can recognize antigens of organism as well as foreign cells. During development if a lymphocyte has receptors for naturally occuring molecules, the cell will be destroyed.

Self VS. Nonself Only lymphocytes that recognize forgein antigens will be left. Leading to specific immunity. Failure to do this leads to autoimmune disease.

Specific Immunity: 3 rd line of Defense B lymphocytes and T lymphocytes: –Circulate through blood and lymph system –Concentrated in the spleen, lymph nodes, and lymph tissues

Specific Immunity: 3 rd line of Defense B lymphocytes – mature in bone marrow T lymphocytes – begin in bone marrow and mature in thymus

Specific Immunity: 3 rd line of Defense –Respond to specific microbes by their antigens (chemical markers on invading materials) –B cells secrete antibody proteins –T cells destroy infected cells

Specific Immunity: 3 rd line of Defense Both B and T cells can form: –Effector Cells – short lived cells to combat same antigen –Memory Cells – long lived cells containing receptors for same antigen

Primary Immune Response The first time the body is exposed to a specific antigen days are required from initial exposure until antigen specific lymphocytes can be produced.

Primary Immune Response While effector B cells and T cells are developed the individual may become ill. Memory Clone cells of both will form.

Secondary Immune Response When the same individual is exposed to the same antigen at a later date. Response is faster - 2 to 7 days. Greater magnitude and more prolonged Antibodies have a greater affinity for the antigen. Immunological memory.

Time of Antibody Production

Humoral Immunity B cell activation results from the production of antibodies that circulate in the blood plasma and lymph fluids. Defenses against: free bacteria, toxins, and viruses in body fluids.

Humoral Immunity Antigen specific B cell binds to antigen B cells grow and divide into: plasma cells which secret antibodies and memory B cells. With aid of Helper T cells.

Humoral Immunity Antibodies released in the blood stream destroy the pathogen. Once defeated plasma cells die out and antibodies are no longer produced.

Humoral Immunity Antibodies attach to membrane / cell wall of pathogen Can cause clumping of pathogen (agglutination) or neutrilization Macrophage will consume by phagocytosis. OR

Hummoral Immunity Antibodies attach to membrane / cell wall of pathogen Compliment protiens attach to two antibodies Compliment proteins are activated and attach to membrane forming a pore. Causes cell to lyse

Humoral Immunity

Cell Mediated Immunity Depends on the action of T Cells Defends against: viruses and bacteria in infected cells, fungi, protists, and parasitic worms. As well as transplanted tissue and and cancer cells.

Cell Mediated Immunity Types of T lymphocytes: –Killer (cytotoxic): Lysis infected cells –Helper : increase responses of B lymphocytes and killer T lymphocytes. –Suppressor: decrease responses of B lymphocytes and killer T lymphocytes

Cell Mediated Immunity Helper T Cells bind to a specific receptor site on a macrophage. A chemical message sent for the production of Killer T Cells and the plasma cells of hummoral immunity.

Cell Mediated Immunity Killer T cells attack infectes/abnormal cells or form memory T cells Killer T cells bind to infected / abnormal cell to a specific receptor.

Cell Mediated Immunity A specilized protien (perforin) is discharged from Killer T cell. Proteins form pores in the cell membrane. Water and ions enter through pores. Cell lyses

Cell Mediated Immunity –Suppressor T Cells: –Release chemicals that inhibit the active killer T cells. –They also inhibit the helper T cells. –Memory T cells last, other T cells die.

Both hummoral and cell mediated immunity occur at the same time.

Immunity Overview