1. Antigen
A substance on the surface of a pathogen that triggers an immune response is called an Antigen (Germ’s fingerprint)

2. Two Divisions of the Immune System
Humoral Immunity
Cell-mediated Immunity
Antibodies mark infected cells for death
Cells attack infected cells

3. Cells of the Immune System
Two types of cells recognize specific antigens:
B Lymphocytes and T Lymphocytes
B-Cell
T-Cell

4. Humoral Immunity
B-Cells - provides immunity against pathogens found in body fluids.

5. Humoral Immunity
Plasma Cell
Antibodies
B-Cell
Pathogens
(Bacteria, Virus, Fungi, Worms, Foreign Proteins)
3. B-cells become Plasma cells, which produce antibodies against the antigen
Antibodies bound to pathogen
2. B-cell recognizes antigen on pathogen
4. Antibodies bind to the pathogen, marking it for death
1. Pathogen invades the body

6. Antibody Plasma cells produce antibodies
Antibodies circulate in the bloodstream and attack the pathogen causing the infection

7. Antibody
Antibodies are proteins that recognize and bind to antigens

8. Antibody
Antigen-Binding Sites
The site that the antibody binds to the antigen is called the antigen-binding site

9. Memory Cells
Some B-cells become memory cells, which are the antibody factory pre-programmed to respond to a returning antigen (i.e. vaccination)

10. Stop Here

11. Cell-Mediated Immunity
T-Cells - provide a defense against abnormal cells and pathogens inside living cells

12. Cell-Mediated Immunity
T-Cell
Killer T Cell
Virus-infected cell
Pathogens
(Bacteria, Virus, Fungi, Worms, Foreign Proteins)
Helper T-Cell
Cell lysis & death
2. Helper T cells activate Killer T cells
1. Pathogen invades the body
3. Killer T cells attack infected cells and quickly kill them

13. Organ Transplant
Cell-mediated immunity makes the acceptance of organ transplants difficult
Your immune system recognizes the transplanted organ as foreign and attacks it - Rejection

14. Organ Transplant
To prevent organ rejection, doctors search for a donor with cell markers close to that of the recipient
Organ recipients take anti-rejection drugs to suppress cell-mediated immune response

15. Summary of the Specific Defenses
Humoral Immunity
Cell-Mediated Immunity
Mechanism
Antibodies
Immune Cells
Cell Type
B-cells
T-cells
Mode of Action
Circulating antibodies
Cell-to-Cell contact
Purpose
Defense against extracellular pathogens
Defense against intracellular pathogens

16. Bacteria-related diseases
Lyme Disease- Rash that leads to muscle aches
Strep Throat- Fever, sore throat, swollen glands
Tuberculosis- Fatigue, weight loss, chronic cough
Do not write, just listen

17. Virus-related diseases
Common cold/flu: Sneezing, sore throat, aches
Hepatitis A-C: Jaundice, fatigue, diarrhea
Chickenpox: Fever and weakness, rash
AIDS: Helper T- cells are destroyed
Do not write, just listen

18. What is immunity?
Immunity - Resistance to a disease-causing organism or harmful substance
Two types:
Active Immunity
Passive Immunity

19. Exposure to actual disease
Active Immunity
Your body produces its own antibodies
Plasma cell
Planned exposure to a form (weakened or killed) of the antigen = Vaccination
Exposure to actual disease

20. Passive Immunity
Antibody is produced by other animals and introduced into your body by injection into the bloodstream or naturally (mother’s milk).

21. How long does active immunity last?
Some disease-causing viruses mutate into new forms that our body doesn’t recognize, requiring annual vaccinations, like the flu shot
Booster shot - reminds the immune system of the antigen
Others last for a lifetime, such as chicken pox
Do not write, just listen

22. Stop Here

23. Antibiotics Compounds that kill bacteria without harming other cells
Prevents cell wall formation
Doesn’t affect viruses since they have no cell wall

24. Immune System Disorders - Allergies
Immune system sees harmless foreign particles as a threat and launches an immune response
Sneezing, runny nose and watery eyes

25. Immune System Disorders - Asthma
Chronic respiratory disease
Air passages become narrower
Wheezing, coughing, & difficulty breathing

26. Immune System Disorders - AIDS (Acquired Immune Deficiency Syndrome)
HIV (Human Immunodeficiency Virus) is the virus that causes AIDS
Specifically targets and kills Helper T-Cells

27. Immune System Disorders - AIDS
Host cell produces new viral particles, which infects new helper T cells
Virus enters the host cell and inserts it’s RNA into the host DNA

28. Tranmission of HIV Any form of sexual intercourse
Sharing needles or syringes
Contact with blood/body fluids
From an infected mother to her child during pregnancy, birth, or breast- feeding

29. AIDS - The Modern Plague
HIV cripples your immune system
Common diseases become life-threatening
Currently no cure, only treatment

30. AIDS - The Silent Spread
An estimated 34.2 million people worldwide have HIV (2011)
2.5 million new HIV infections in 2011
Sub-Saharan Africa is a largest region with HIV positive people
Do not write, just listen

31. Stop Here