The Immune System

Understand the inflammatory response, including the role of macrophages, mast cells, cytokines, histamine, monocytes, neutrophils, vasodilation, and phagocytosis.

1. Activation of macrophage --> phagocytosis, cytokines. Macrophages and mast cells hang out in tissue but can't eat everything right away so they release cytokines (communication molecules and they activate other responses and guide other cells to the area. 2. Histamine release from mast cells --> causes vasodilation and capillary permeability 3. Increased capillary permeability causes gaps in blood vessels and plasma proteins leave blood vessels and create a wall around damaged area to trap bacteria so it doesn't spread. This results in swelling!! 4. Leukocyte migration. Leukocytes leave blood vessels and are able to clean up damaged tissue and eat bacteria. 5. Phagocytosis of bacteria and debris. Pus is leukocytes and digested tissues.

Know the 5 ways in which antibodies can fight infections.

1. Agglutination: clumping together of cells joined by antibodies. A bunch of antibodies working together so macrophages can eat everything. 2. Opsonization: bacteria/virus made more prone to phagocytosis. Macrophage recognize that antibody's tail. Bind to the tail region. Makes it easier for the phagocyte to eat the bacteria. 3. Neutralization: poisons are made non-toxic. Bacteria is producing toxins. Antibodies bind to toxin and toxin can't enter cell. 4. Activation of complement system: C1 becomes activated and bind to tail region of antibody. 5. Stimulation of natural killer cells. Bind to tail region and activates them. Kill by lysis.

Which immune processes are categorized under innate immunity?

Inflammation Interferon Natural Killer Cells Complement System

Understand the difference between innate and adaptive immunity.

Innate: non specific, inherited, non-selectively defend against foreign invaders, first line of defense, limited response, quick but weak. Adaptive: specific immunity, organism adapts to defend against specific invaders, slow but powerful.

What is a memory cell?

Like a clown. They are more ready to activate if exposed to an antigen. Enhances ability to fight an antigen.

What role does MAC play? What is the MAC made up of?

Membrane Attack Complex. Made up on complement proteins. When C1 is activated a cascade of reactions results in MAC formation --> lysis of bacteria. Basically pokes holes in the membrane until the cell dies.

Understand the role of the complement system in immune function. How does the system right infection?

Non-specific defense system produced by the liver. System is made up of 9 proteins (normally inactive). When they are cut they become activated.

Understand the role of Natural Killer Cells in the immune system. What types of cells do they attack? How do they kill? How are they different from cytotoxic T-cells?

Non-specific they attack any virus infected or cancer cell. Rapidly activated. Limited in their response (fewer number than activated T-cells)

How does it destroy the infected or foreign cell?

Once activated, the T-cells undergo repeated mitosis, producing an "army" of T-cells specific for that viral infected or cancer cell. Cytotoxic T-cells then destroy targeted cells. Killer cell bind to target cell. Killer cells exocytosis perforin released. Perforin molecules are activated by calcium. Higher levels outside the cell. Perforin molecules change shape. Insert into membrane of target cell. Form a pore until it punched holes in membrane so the cell breaks. Once cells is destroyed the free virus is attacked by macrophages antibodies and the complement system.

What is the difference between primary and secondary immune response?

Primary: takes 1-2 weeks for antibodies to get fired up. Indicated that b cells have become activated and plasma cells are creating antibodies. Secondary: Antibodies levels shoot up really quickly. Doesn't given body time to feel sick. What we call immunity. You body becomes immune to a certain pathogen.

Understand the role of lymphocytes in immune function

Product of cell-mediated immunity. Directly attack unwanted cells.

What are major histocompatibility complex self-antigens? How does the cytotoxic T-cell recognize foreign or virally infected cells? How does it destroy the infected or foreign cell?

T cell receptor recognize foreign antigen only when complexed to a class 1 major histocompatibility complex molecule. When the virus gets inside the cell. It is going to be digested and produce antigens. Antigens are going to be recognized by class 1 MHC. recognizes proteins and antigens that aren't apart of you. They bind and they present them at the membrane. Exposed so cytotoxic T cells because they have antigen receptors. Only binds with the antigen is presented.

Understand how B-lymphocytes become activated. What is the difference between a b-lymphoctye and a plasma cell?

When an antigen is exposed to a B cell, the B cell has a receptor that recognizes the antigen. Plasma cells are when the B cell starts dividing. Plasma cells are to produce antibodies. They dispose of the antigen.

What is an antibody?

Y shaped. Able to bind only with the specific antigen that "fits" its antigen binding sites on the tips. The tail region binds with mediators.

What are NSAID's and how do they decrease inflammation?

non- steroidal anti-inflammatory drug Decrease inflammation by inhibiting the production of prostaglandins (which leads to fever) and histamine. Blocks Histamine. Inflammation is important so sometimes it shouldn't be block because immune system can't fight off infection.

Understand how interferon defends against viral infection. Where and why is it produced? What effect does it have? Where does it have its effect?

1. Virus enters a cell and replicates in invaded cell. 2. Cell release interferon 3. Interferon binds with receptors on uninvaded cells on cell membrane. Tell it to start producing enzyme. 4. Uninvaded cells produce inactive enzymes capable of breaking down viral messenger RNA and of Inhibiting protein synthesis. 5. Virus blocking enzymes are activated. 6. Virus is unable to multiple in newly invaded cell.

By what 2 methods is the complement system activated?

Alternate complement pathway: nonspecific binding to CHO chains on bacteria. Classical complement pathway: binding to antibodies specific to that bacteria. Once pathway is activated it will enhance inflammation, chemotaxis, opsonization (grabbing), mast cell activation, and vasodilation.

Which immune processes are categorized under adaptive immunity?

Antibody-mediated immunity cell-mediated immunity inflammation interferon Natural killer cell action complement system

Understand the role of B-lymphocytes in immune function. Where do they come from and what do they do?

B cells come from the bone marrow. Circulate in the blood but end up in the peripheral lymphoid tissues. When there is a foreign invasion it activates the B cells. B cells will do ANTIBODY mediated response.

What triggers the production of antibodies? What is clonal selection theory?

Clonal selection theory: millions of different lines of B cells are generated during fetal development. Each line of clones has cell-surface receptors specific for a certain antigen. These cells are naive or dormant until activated by a given antigen. Selected B-cells differentiate into plasma cells and memory cells.

What are 3 types of T-cells, and what are their general roles?

Cytotoxic T Cells: destroy cancer cells and virus infected cells- direct contact. Have specific "T-cell receptor" on plasma membrane Helper T cells: enhance activity of cytotoxic T cells, B cells, and macrophages by secreting cytokines. Coordinate the attack. Suppressor T cells: suppress B cell antibody production, cytotoxic T cell activity and helper T cells so they don't get immune system fired up.

Understand how vaccinations work. Why don't they normally make one sick?

Either dead or attenuated pathogen is injected. Attenuated means that the pathgoen can no longer cause disease but it still has its antigenic portions. The body mounts an immune response against the pathogen that leads to memory cell production. Then when exposure to the real pathogen occurs, the immune response is fast and powerful so that no symptoms occur.

Understand why and how fever occurs.

Endogenous pyrogen in the blood is released by cytokines, sends signal to hypothalamus, stimulates prostaglandin release, which increases body's thermostat.