Immune System, Vaccines, and Antibiotics Part 2

1. Immune System, Vaccines, and Antibiotics Part 2 Biology EOC Review SC.912.L14.52 By M. Donohue

2. What is Immunity??? • Brainstorm! • Raise Your Hand!

3. The Immune System What is homeostasis? Why do you think the immune system plays a role in homeostasis? Your Body Fighting Against Evil Invaders! • Disease disrupts stability of an organisms STABLE INTERNAL environment • Immune systems helps MAINTAIN stability…AKA HOMEOSTASIS • Immune System: • The organ system that protects the body from disease • Made up of specialized cells and organs that work together to protect you from pathogens • Infection- the multiplication of a pathogen in body tissue • Three different lines of defense…we will get to these in a bit…

4. How Do We Build Immunity? Your body marks the attackers, herds them together, and DESTROYS them! • You have to make ANTIBODIES!!! • Remember those? • Definition: protein produced by white blood cells (WBCS) • Attaches to antigens of invaders using ”lock and key” mechanism • Antigens are proteins on the surface of call cells and viruses…their id card • Antibodies cause antigens to clump together=easier for your body to attack and destroy • Antibodies in a nutshell Mark invader and herd them together so they can be easily destroyed by other WBCs (white blood cells) • Well how does our body do that? • Two different ways…. • Active Immunity • Passive Immunity

6. Two Major Types of Immune Responses • Passive Immunity • Created by transferring antibodies made by one organism into another organism • Ex. Rabies • Often acquired before birth during fetal development • Newborns receive antibodies through their mother’s milk • Active Immunity • Results from exposure to pathogen • Can occur naturally… • Pathogen enters body • immune system makes antibodies…AKA you get sick • Can occur by VACCINATION • Weakened or deactivated virus introduced to body to make antigens • Doesn’t usually make you sick • Next time a person gets infected, their body rapidly makes antibodies to destroy pathogen

7. Overview of Vertebrate Defenses against pathogens

8. Introducing Your Immune Systems 3 Lines of Defense!

9. The Immune Systems 3 Lines of Defense #1: Barriers! Non-specific #2: Inflammatory Response! #3: Immune response! SPECIFIC

10. The Immune Systems 3 Lines of Defense • #1: Barriers to Infection (nonspecific) • Function-keep invaders (pathogens) OUT of your body • Skin • Mucous membranes (respiratory tract) • mucus traps pathogens • cilia moves it out of your throat and nose or into stomach (sneeze, cough, swallow) • Mucus, Saliva and tears • contain enzyme lysozyme (enzyme that breaks down cell walls of bacteria) • Perspiring (sweat and oil) • liquid waste secreted from pores that contains acids, salts and enzymes that kill bacteria on surface of skin

11. The Immune Systems 3 Lines of Defense • #2 Inflammatory Response (nonspecific) • Function- respond to the invaders that have entered the body and have started to damage precious tissue • White Blood Cells WBCs • Several different types specialized to fight disease • Blood vessels near injury WIDEN(dilate) to let more blood flow to area of injury • Plasma fills spaces between cells • Plasma carries WBCs called MACROPHAGES to injury site • MACROPHAGES- large WBCs that engulf and destroy pathogens and alert other immune cells • Area is swollen b/c of increased blood flow • Fever- increase in temp. makes more less suitable for growth of bacteria and MACROPHAGES work more efficiently

12. The Immune Systems 3 Lines of Defense • #3: Immune Response (specific) • Function-specialized attack on SPECIFIC pathogens that have invaded the body • Many WBCs involved • Macrophages, T cells, and B cells • WBCs secrete antibodies, a protein that attaches to specific region of foreign substance called the antigen

13. Meet the Troops • Who are the warriors saving our bodies? • Phagocytes • cells specialized in finding and "eating" bacteria, viruses, and dead or injured body cells. • There are three main types • the granulocyte • the macrophage • the dendritic cell • Lymphocytes • migrate to parts of the lymphatic system • T cells and B cells

14. Phagocytes • The granulocytes often take the first stand during an infection. • Sacrifice them selves in battle…gobble up invaders until they die  (thank you brave warriors…) • The macrophages ("big eaters") • slower to respond to invaders than the granulocyte but they are larger, live longer, and have far greater capacities • ALERT the rest of the immune system of invaders. • The dendritic cells are "eater" cells and devour intruders • Helps ACTIVATE rest of immune system • filter body fluids

15. Lymphocytes (specialized attackers) • On the surface of each lymphatic cell are receptors that enable them to recognize foreign substances. • very specialized receptors- each can match only one specific Antigen- • protein on the surface of a cell (good or bad) that signals to other cells what it is • T cells • T cells come in two different types, helper cells and killer cells. • B cells • JOB: search for antigens matching its receptors, connect and become PRATIALLY ACTIVATED • FULL ACTIVATION require proteins from helper T cells • Once FULLY ACTIVATED: • the B cell starts to divide to produce clones of itself called plasma cells and B memory cells.

16. T Cells • Two types • Helper T cells main regulators of the immune defense • JOB: activate B cells and killer T cells. • must be activated by antigen presentation • ACTIVATED Helper divides and to produces PROTEINS that activate B and T cells • Killer T cells • specialized in attacking cells of the body infected by viruses and by bacteria (and sometimes cancer cells) • Recognize antigens on invaders and swiftly kill the EVIL invader

20. B Cells (2 types) • The plasma cell • Job: Make antibodies that search for other similar invaders • Antibody finds invader, attaches to it and attracts macrophages to come over and gobble up the invader • Some Antibodies also neutralize toxins and incapacitate viruses, preventing them from infecting new cells. • The Memory Cells • Prolonged life span and can thereby "remember" specific intruders (T cells produce even better ones) • The next time the same invader comes into body, B and T memory cells help the immune system to activate much faster • Invaders are wiped out before the infected human feels any symptoms • Immunity against the invader has been achieved

24. Once the battle is done, the T-suppressor cell calls off the troops so they can rest up for the next battle!

25. Nonspecific vs. specific defenses • Nonspecific defenses do not distinguish one infectious microbe from another • Specificdefenses recognize and defend against invading microbes and cancer cells • Involves presence of an antigen

26. Nonspecific defenses • Skin • Mucus • Macrophages • Inflammatory Response • Interferons and complement proteins • attack microbes either directly or indirectly by impeding their reproduction • Interferons are produced by infected cells • Diffuse to healthy cells where they cause the cell to inhibit viral production • Complementproteins are activated by microbes or immune system • Coat infected cells –easier to eat • Can amplify inflammatory response

27. Nonspecific defenses: inflammatory response

28. Nonspecific defenses: inflammatory response • Redness, heat, and swelling caused by • Increase in blood flow, fluid, and cells • Inflammatory response disinfects and cleans injured tissues • Pus = dead white cells and fluid • Systemic response is widespread • Toxins or microorganisms released in bloodstream • Circulates through body • Inflammatory weapons • increase white blood cells, • Fever • Low-grade fever can stimulate phagocytosis and inhibit growth of many microorganisms

29. Specific immunity • Often more effective than nonspecific response • It also amplifies nonspecific response • Specific response begins due to presence of an antigen • Can either increase # of cells that attack invader directly OR • Produce antibodies • Immune system “remembers” antigens it has previously encountered • Responds immediately and vigorously • Is adaptive

30. Antibiotics • What happens when your body can’t fight off infection? • Must call for extra help…Medicine/drugs called ANTIBIOTICS • Drugs used to either kill bacterial or prevent reproduction • Penicillin-1st antibiotic • 1928 • Used to be effective against many bacterial infections • Today, it is the least effective antibiotic against many of the infections it fought • Why??? • See next slide….

31. Bacterial Resistance to Antibiotics • Why do some antibiotics stop working??? • Antibiotic usually kills entire colony of bacteria • Sometimes a few little suckers survive • They develop their own immunity/resistance to the antibiotic (it’s in their simple DNA)…EVOLUTION! • These resistant bacteria reproduce ASEXUALLY and pass off instructions for resistance to offspring • Their little super army of resistant bacterial clones grows quickly over time and occurs every time antibiotic is used • Eventually there may be so many resistant bacteria that the antibiotic won’t work…BIG PROBLEMS! • Need to find a new strategy of attack • SOOOOO…do NOT use antibiotics every time you feel sick…only use when they are prescribed by your Doc!

33. Explain why this is true…

34. Let's see exactly how this all works...CLICK ME!!!!

35. Summary (What you need to know) • Nonspecific vs. specific Immunity • As organisms have become more evolved, SPECIFIC Immunity has developed (helps in survival and reproduction) • Active vs. passive immunity • Antibodies • Protein that attaches to the antigens of invaders and signals to immune cells that it needs to be destroyed • Antigens • Proteins on the surface of cells that indicate to other cells what it is • Macrophages • First ones to Gobble up invaders • T Cells • Attack specific invaders and kill them • B Cells • Produces Antibodies against the invader