Immune System Mr. Karns Biology Chapter 40 Immune System Mr. Karns Biology

Color Coding Red – most important Orange – next most important Yellow – it is o.k. to write it down White – you likely do not need to write it down Taking notes is about deciding what is important and deciding if you can look it up later or not

Infectious diseases Pathogenic (disease-causing) Methods of transmission Airborne droplets: chicken pox, flu, influenza Direct contact: cold sores, Hepatitis B, C Exchange of bodily fluids: STD’s – HIV/AIDS, syphillis, gonorrhea Objects Contaminated H2O: polio, cholera Contaminated food: botulism, E. coli (some strains only) Vectors: Lyme disease (ticks), malaria (mosquitoes), bubonic plague (fleas)

SNEEZE VIDEO Just Watch and Enjoy 

Determining cause of a disease Koch’s Postulates

SCIENTIFIC METHOD - Koch’s Postulates 1. Identify pathogen every time 2. Isolate & grow 3. Infect healthy organism 4. Isolate from new host (and grow it again if you need to) [Note: This method doesn’t work with syphilis organisms nor viruses.] (Viruses can’t be grown outside of a living cell, so #2 above won’t work)

Reservoirs of infectious organisms Human beings Carriers: people who contain pathogens and pass them on to others before any symptoms show in themselves. Incubation period = time during which organisms are multiplying and before any symptoms show up. Animals Birds, insects, mammals Soil Botulism and tetanus bacteria, anthrax (or in poorly processed canned food)

What do pathogens do to cause disease? Bacteria produce toxins Cause fever, inhibit protein production, destroy RBCs and blood vessels, cause spasms (by disrupting nervous system impulses) Ex. tetanus toxin: causes uncontrolled muscle contractions -- eventually paralysis and death Viruses multiply in cells, lyse (burst) some cells as they multiply and thereby injure tissues.

Spread of disease know these three terms Endemic disease: low-level of infection which is constantly present in a population Epidemic: a localized outbreak of a disease Polio outbreak during 1950s Pandemic: world-wide outbreak of a disease Influenza of the early 1900s

How to treat infections Antibiotic: chemical substance produced by a microorganism which can inhibit the growth and reproduction of other microorganisms. Produced by many bacteria and fungi, sponges Work on gram positive bacteria Cause the cell wall to breakdown (lysis) Nothing good available to inhibit viruses (AZT is a reverse transcriptase inhibitor used to treat HIV infections with AIDS)

A Potential Problem The overuse of antibiotics kills off all the sensitive pathogens -- only the mutant resistant pathogens remain to repopulate. Penicillin-resistant syphillis organisms (produce penicillinase) Drug-resistant strains of tuberculosis bacteria already exist

Non-Specific Immunity Skin Inflammation Phagocytosis (Innate Immunity) Macrophages (1st line phagocytic defense) Neutrophils (2nd line of phagocytic defense) Monocytes (3rd line of phagocytic defense)

Nonspecific immunity Innate immunity: “inborn” immunity 1. Skin Physical barrier Secretions (skin, nose, lungs, etc.) Mucus Sweat (some enzyme lysozyme) Tears (much enzyme lysozyme) (Alexander Flemming discovered) Saliva (some enzyme lysozyme) Gastric juice (HCl and other chemicals kill lots of bacteria) the skin has a pH between 3 and 5, which is acidic enough to prevent colonization of many microbes

2. Inflammation process Caused by Histamine release! a. Reddening of area because blood vessels dilate b. Swelling c. Pain d. Heat

Phagocytes Phagocytes are white blood cells that ingest and destroy pathogens. What are the three phagocytes? Phagocytosis is the process by which phagocytes ingest and destroy pathogens

3. Some White blood cells are phagocytes (“eating” cells) Microbes MACROPHAGE Vacuole Lysosome containing enzymes 3. Some White blood cells are phagocytes (“eating” cells) Tissue macrophages (“big eaters”) – Neutrophils (WBC) can phagocytose bacteria – Monocytes (large WBC which become macrophages) – Macrophages and neutrophils die after “eating” pathogens; along with dead tissue cells and plasma, they make pus!

Phagocytosis Video

Puncture Wound Video Be prepared to draw a diagram of the process!

Lymphatic system Lymph capillaries Lymph vessels Lymph Nodes Thymus T cells mature Spleen Storage of WBC & RBC Tonsils

Purpose of Lymph System Return tissue fluid (previously blood plasma) back to heart and into circulation Tissue fluid is called lymph once it enters lymphatic vessels

General arrangement of capillaries and lymphatic vessels (green)

Lymph nodes Contain lymphocytes (WBCs) which... Defend body against foreign substances Filter lymph of most bacteria

White Blood Cells = Leukocytes Phagocytes: Macrophage Neutrophil Monocytes Lymphocytes T cells (Helper, Cytotoxic and Memory T-cells) Mature in the thymus B cells (Memory B cells and plasma cells) RED and WHITE blood cells are produced in bone marrow

Specific Immunity Acquired Immunity Passive Active Antibody Immunity (Humoral Immunity) Cellular Immunity (for viruses, cancer cells, tumors)

Antibodies react with antigens and do several things

Antibody (humoral) Immunity Be prepared to draw the process of humoral immunity.

.Helper T cells are important !

.Cytotoxic T cells are Killer T cells

Steps of Antibody Immunity Displayed antigens

Cellular Immunity for Viral Defense Be prepared to draw the process of cellular immunity

Draw a diagram of the cellular immune response. You may work in groups of three, but everyone needs to draw the diagram.

Cellular Immunity (Cytotoxic = Killer) Lesion = opening Perforin = cluster of proteins which make a Lesion (hole).

Interferon Proteins Produced by virus-infected cells Interferons are host-specific (human proteins only work for humans, etc.) Interferon act as an “alarm” molecule to uninfected cells Uninfected cells produce antiviral proteins which prevent viruses from entering them. [Summary note: cells of innate (nonspecific) immune system constantly monitor tissues for foreign invaders and attempt to suppress the “invasion”.]

Allergy (can be specific or non-specific) Is an exaggerated reaction to antigens A 2nd exposure to an environmental Ag causes the typical allergic reaction Histamines affect tissues throughout whole body similar to an inflammatory reaction. (pollen grain)

1983: HIV -- is a retrovirus (RNA virus; 1983: HIV -- is a retrovirus (RNA virus; contains reverse transcriptase to reproduce itself in a host cell) HIV infects and kills helper T cells Nearly all HIV carriers will have AIDS and will die from cancers or opportunistic infections.

HIV structure and infection of helper T cell

HIV / AIDS / Immune System 1981: rare types of pneumonia and skin cancer (Karposi’s sarcoma) noticed in San Francisco Nonfunctioning immune systems in patients Purple splotches common in Karposi’s sarcoma

HIV budding from helper T cell

HIV

End It’s time for TEST Review

1. A general type of “eating” cell is called a __________ . phagocyte 2. A specialized type of big “eating” cell in the immune sytesm is called a ________ and is usually considered to be part of nonspecific immunity. macrophage

3. AIDS is a disease of the immune system because HIV infects and kills the ___________ cells which are important in developing an immune response. Helper T 4. Organ transplants procedures require the patient’s immune system to be suppressed before the procedure begins? Why? To prevent cellular immunity methods from rejecting the donated organ.

Easy questions

Question 1 Diseases that are constantly present in the population are called _____ A. endemic diseases B. epidemic diseases C. immunity diseases D. resistant diseases

Question 2 Who first proved that a specific microbe caused a particular disease? Jenner B. Mendel C. Darwin D. Koch

Question 3 While in the lymphatic vessels, tissue fluid passes through structures called _____ that filter the fluid. A. lymphocytes B. lymph nodes C. thymus glands D. mucus traps

Question 4 Which of the following are part of the nonspecific defense (innate immune system) against diseases? A. B cells B. T cells C. plasma cells D. macrophages

Question 5 Which cells are attacked by HIV? B cells B. T cells C. plasma cells D. macrophages

Medium Difficulty questions

Question 1 A baby is born lacking a thymus gland. What cells are missing in the child? B cells B. T cells C. plasma cells D. macrophages

Question 2 What is the relationship between tissue fluid and lymph? A. Tissue fluid leaks out of blood vessels and is called lymph when it enters lymphatic vessels. B. Tissue fluid surrounds the body cells, and lymph circulates throughout the body in the lymphatic system. C. Lymph leaks out of the blood. It is then called tissue fluid. D. Tissue fluid is the liquid portion of the blood. When it leaks out of the capillaries, it is called lymph.

Question 3 What is the function of a booster shot? A. Some individuals are allergic to the first shot, so they need more than one shot. B. The booster vaccines contain different materials. C. When the body is re-exposed to a disease agent, it forms more memory cells for immunity. D. A booster shot will activate different cells of the immune system from those activated by the first vaccine.

Question 4 Why do patients with AIDS continually battle infectious diseases? A. AIDS patients are infected with the HIV virus. B. AIDS causes the production of interferon. C. AIDS destroys the plasma cell response to infectious diseases. D. AIDS weakens a patient's immune response to infectious diseases.

Question 5 Why does a vaccination give long-lasting protection against a disease? A. Vaccines increase the level of antibodies in the bloodstream. B. Vaccines contain dead or weakened disease agents. C. Vaccines prevent the body from responding to disease agents. D. Vaccines cause the body to create memory cells that are prepared to fight any future encounters with the disease organism.

Difficult questions

Question 1 (analogy) Virus-infected cells are to interferon as plasma cells are to _____ A. complement B. lysozyme C. antibody D. helper T cells

Question 2 When a patient receives a kidney transplant, the patient's immune system is suppressed by the use of prescribed drugs. Why would this be important and necessary? A. Without this suppression, the immune system would attack the foreign transplanted tissue. B. The suppression will stimulate the immune system to work more efficiently. C. The suppression will stimulate the bone marrow to produce more white blood cells. D. Without the suppression, the body will secrete too many hormones.

Question 3 Why might a physician recommend against taking a fever-reducing medication when you have an abnormally high temperature? A. A high temperature activates the immune system. B. A high temperature inhibits the growth of some disease-causing bacteria. C. A high temperature decreases blood flow, so the disease will spread more slowly. D. A high temperature inhibits the body's repair.

Do well on your test :) That’s all . . .

A bit of a review and some detail follows. Watch carefully I will move quickly.

Cellular immunity, cancer, & organ transplants Cytotoxic (Tc) cells will “lock onto” any cell which presents a “foreign” molecule Virus-infected cells present an Ag in the midst of their own self marker molecules (new markers are made continuously) Malignant cancer cells present unusual molecules which attract Tc cells; Tc usually keep cancer cells “in check” Some types of cancer lose their ability to continue making self marker molecules and don’t present the unusual molecules which ordinarily attract Tc cells. Transplanted organs may contain slightly different self markers and attract Tc cells Immunosuppressant drugs such as cyclosporin A are used before, during, and after the transplant procedure to avoid activation of helper T cells.

Acquired immune response Self components of a person’s own body Self marker is a cluster of proteins on plasma membrane surface; cluster is a “protein fingerprint” -- unique for each person (real term = major histocompatiblity complex) Foreign substances are nonself. Nonself molecules are called antigens Pollens, dust particles, animal dander, bacteria, viral proteins, etc. Acquired immune response is a process of producing specific antibodies against specific antigens Acquiring immunity takes time (up to 2 weeks)

Thymus gland Immature lymphocytes mature into T cells Gland declines in size by adolescence

The Spleen Contains lymphocytes Filters and destroys bacteria Removes old RBCs from circulation; liver converts them into bile

Antigen-Antibody binding is specific

Two kinds of acquired immunity Antibody (humoral) immunity Antibodies circulate in the blood (humor) Cellular immunity Antibodies remain attached to immune cells (lymphocytes) Acquired immunity is SPECIFIC and occurs simultaneously with Innate or non-specific immunity.

B T Lymphocyte: basic cell of immune system Made in red bone marrow from stem cells T B

Specific immunity Occurs simultaneously with innate immune cells Certain white blood cells (lymphocytes) “learn” to recognize foreign substances and react specifically to them. These cells can eventually inactivate/destroy pathogens This takes time (from days up to 2 weeks). Immunity which results is called acquired immunity.

Two categories of lymphocytes B cells -- have only been exposed to bone marrow T cells -- spend time in and mature in thymus gland; receive additional attributes beyond B cells May circulate in the blood or reside in lymphoid tissues/organs

T cells M T T B B Plasma cells Helper T cells interacts with Antigen-presenting macrophages or Antigen-presenting B cells M a. Macrophage with ingested pathogen, b. In a food vacuole, c. Presenting pathogen d. Helper T cell binds to macrophage self markers; T cells become stimulated by binding to the antigens on macrophages T e. Activated T cells bind to B cells; f. B cells divide rapidly into plasma cells and memory cells B B T Memory B Cells Clone Plasma cells Y Antibodies in blood and tissue fluid

B cells can bind antigens directly Helper T cell releases chemical (interleukin) which activates B cell to divide. Memory B Cells Clone Y Plasma cells Y

From nonspecific defense to production of antibodies

Summary Many B cells to select from Only one kind of B cell becomes activated by a specific antigen Most memory cells last our whole life.

Primary/Secondary Responses

The complement cascade Complement = about 20 proteins in blood Complement proteins self-assemble to make a lesion in plasma membrane; cell lyses

Examples of perforin lesions Cancer cells

Two types of acquired immunity 1. Passive: receive antibodies from another source -- person, animal, genetically- engineered antibodies from bacteria Ex. Antibodies from mother -- through the placenta; through breast milk Ex. Injection of pooled serum (from many donors) and its diversity of antibodies from donors.

2. Active: antibodies obtained naturally by having an infection of a pathogen OR Receiving a Vaccine of . . . Dead or weakened pathogens (viruses, bacteria) Edward Jenner (1798): use cowpox virus to vaccinate against smallpox -- cowpox protein shapes are similar enough to smallpox to give immunity Which type of immunity is longer-lasting -- passive or active?