Immunity Learning Targets 2-11

Disease Basics Disease Disease – any change that disrupts the normal function of an organism Caused by… – Bacteria – Viruses – Fungi – The environment Pathogen Pathogen – any disease causing agent LT 3

Disease Basics How are Diseases Spread: 1.Physical contact between members of the species 2.Contaminated food or water 3.Infected animals How to Fight Diseases: 1.Preventative Behaviors 1.Preventative Behaviors - hand washing, wastewater treatment plants, sewers 2.Drugs a.AntibioticsNOT VIRUSES, a.Antibiotics-destroy bacteria, NOT VIRUSES, without harming host cells…some are naturally occurring (penicillin) or man-made b.Antivirals- b.Antivirals- drugs made to inhibit or prevent viruses in cells or from entering cells (ex: flu vaccine) 3.Immunity 3.Immunity- an organism’s own natural defenses that recognize, attack, destroy and “remember” pathogens using specialized cells or barriers. LT 3

Immunity There are two kinds of immunity 1.Natural Immunity non-specific and specific 1.Natural Immunity- cells, tissues or products naturally occurring in an organism that fight against pathogens; non-specific and specific 2.Acquired Immunity active and passive 2.Acquired Immunity-developed by exposure to a vaccine or exposure to another animal’s antibodies; active and passive LT 4

Natural Immunity Non-Specific Defenses “Castle Wall” Physical or chemical barriers that attempt to keep pathogens out. First Line First Line – Includes the skin, mucous, sweat, tears or saliva Second Line -- White Blood Cells (WBC) Fever Interferons Specific Defenses “The Soldiers” Specialized cells that track down and attempt to destroy pathogens that have managed to get in Third Line - B Lymphocytes/Humoral Immunity- protection of body’s liquids T Lymphocytes/Cell-Mediated Immunity T Lymphocytes/Cell-Mediated Immunity – protects against abnormal cells or pathogens in cells

Non-Specific Natural Immunity Keeps most pathogens out Does not discriminate between one threat or another 1.First Line-Skin, mucous, sweat, tears Lysozyme -Contain a protein enzyme called Lysozyme that breaks down the cells of pathogens 2.Second Line-Inflammatory Response a.A response to injury or infection WBC called phagocytes b.If the pathogen does get in WBC are made in the millions and engulf and destroy the pathogen-called phagocytes called a fever c.The body will also release chemicals to increase the core body temperature-called a fever; high temperatures can kill most pathogens and increase heart rate to get WBC to site faster 3.Interferons- (watch this) (watch this)(watch this) virus-infected -proteins made by virus-infected cells -slow down the reproduction of viruses to allow the specific defenses time to respond. LT 5 & 6

White Blood Cells (WBC) Blood contains… 1.Red Blood Cells 1.Red Blood Cells-carry O 2 2.Platelets 2.Platelets-help with clotting 3.White Blood CellsIMMUNITY 3.White Blood Cells-involved in IMMUNITY Other Facts leukocytes Also called leukocytes Do not carry O x less common than RBC Produced from unspecialized cells in the bone marrow Can live for days or years Guard against infection, fight parasites, and attack bacteria Guard against infection, fight parasites, and attack bacteria A high number of WBC indicates some sort of infection Three kinds of WBC Three kinds of WBC 1.Phagocytes 1.Phagocytes – engulf and digest pathogens 2.Histamine Producers 2.Histamine Producers – increase blood flow as an inflammatory response 3.Lymphocytes 3.Lymphocytes – B and T-Cells LT 7

Phagocyte - type of cell capable of engulfing and absorbing bacteria, small cells and particles; EX: WBC Phagocytosis – ingestion of bacteria or other material by phagocytes Pseudopodia- a protrusion of the cell membrane caused by cytoplasmic streaming; used for movement or “feeding” Phagosome- a vacuole/sac in the cytoplasm of a cell containing any materials ingested during phagocytosis Lysosome - an organelle in eukaryotic cells that have enzymes that digest worn out organelles, cell parts or food particles

WBC Phagocyte Phagocytosis Pseudopodia Phagosome Lysosome

Specific Natural Immunity get past Utilized when pathogens get past the non-specific defenses The immune response is triggered Antigen(protein) Antigen- a substance (protein) that triggers an immune response (ex: virus, bacteria, protists) Cells in the Immune System that recognize antigens: 1.B-Lymphocytes (B-Cells) 2.T-Lymphocytes (T-Cells) LT 8

Humoral Immunity (B-Cells) 1.A pathogen enters the body antigens are recognized by B Cells lymphocytes 2.The pathogen’s antigens are recognized by B Cells (specialized cells-lymphocytes-that produce antibodies to attack pathogens) Plasma Memory cells 3.This prompts the B-Cells to start dividing rapidly into Plasma and Memory cells plasma cells Antibodies 4.The plasma cells make antibodies. Antibodies are special proteins that recognize and bind to the antigens to try to destroy them. The ends of the Y-shape of the antibody matches the shape of the antigen LT 8

Humoral Immunity (B-Cells) 5.Memory cells remember pathogens encountered and can quickly reproduce antibodies if exposed to that antigen again 5.Memory cells are also produced from the B- Cells. These cells remember pathogens encountered and can quickly reproduce antibodies if exposed to that antigen again. They are not active during the first exposure. plasma cells and more memory cells 6.If the antigen comes back the Memory cells will divide into plasma cells and more memory cells to produce the specific antibodies needed again.

Cell-Mediated Immunity (T-Cells) ! NOT ASSOCIATED WITH ANTIBODIES ! 1.T-Cells defend against our own bad cells (like cancer cells) or cells infected with viruses. 1.T-Cells are specialized cells that defend against our own bad cells (like cancer cells) or cells infected with viruses. 2.If a pathogen is in a cell, antibodies cannot get into the cell to fight it. 3.Infected cells will have antigens of the pathogen on their surface that T-Cells can recognize and bind to. four kinds 4.T-Cells will divide into four kinds of cells to do this a.Helper T-Cells a.Helper T-Cells-produce memory T- cells and activate B-Cells b.Killer T-Cells- b.Killer T-Cells-track down and destroy pathogens with antigens c.Memory T-Cells c.Memory T-Cells-if a second exposure to the same antigen occurs they are involved (like Memory B- Cells) d.Suppressor T-Cells d.Suppressor T-Cells-turn off Killer T- Cells LT 9

T-cells are also important because they activate B-Cells!! pathogen’s antigens on their cell surface 1.Phage cells can put can put the pathogen’s antigens on their cell surface to be recognized by T-Cells. 2.Helper T-Cells specifically bind to the antigens. Helper T-Cells to become killer T-cells and to activate B-Cells 3.Chemicals are sent out and signal Helper T-Cells to become killer T-cells and to activate B-Cells 4.Killer T-Cells 4.Killer T-Cells will bind to antigens and destroy the cell, thus destroying the pathogen. 5.B-Cells 5.B-Cells differentiate and make plasma cells with antibodies.

Cell-Mediated Immunity (T-Cells)

Acquired Immunity Active Acquire Immunity -immunity produced by a body’s response to a vaccination or natural exposure to an antigen Vaccine weakened form Vaccine – the injection of a weakened form of a pathogen to produce an immune response after Appears after an exposure to a pathogen Body produces antibodies against the pathogen Passive Acquire Immunity -immunity gained temporarily by being injected with another organisms antibodies Short lasting Short lasting because foreign antibodies are eventually destroyed naturally (from mother as a fetus or from breast-feeding) deliberately (injections) Developed naturally (from mother as a fetus or from breast-feeding) or deliberately (injections) LT 11

Acquired Immunity Questions Vaccinations 1.I got chicken pox as a child. Why haven’t I gotten it again. Explain. 2.Since I have had the chicken pox virus, I will be protected against the measles virus, right? Why or why not? 3.Why is a vaccine like a sneaky little trick to your immune system? 4.Why do I only need a tetanus virus every so often but a flu virus every year? I hate shots! Explain Mother to Baby 1.During which trimester of pregnancy are antibodies passed from mother to baby? 2.If a baby is born prematurely, how does this affect their immunity? Why? 3.A mother’s milk takes a few days to be produced. Should a mother even bother nursing her baby in the hospital or wait until she gets home? Why? 4.My doctor recommended my husband and I get the Pertussis or Whooping Cough vaccine before my baby was born. Why?