1. Infectious Disease and the Immune System

2. Viruses Viruses are non-living.
Only characteristic of living organisms is ability to reproduce.
Obligate intracellular parasites.

3. Viruses Viruses are composed of; a nucleic acid- can be dna OR rna.
Protein coat called a capsid which can be different shapes; helical, polyhedral
Some viruses have an envelope of lipids that surround the capsid when they leave a host cell

4. Viruses
Virus types:
DNA viruses.
RNA viruses.

5. Viruses Retroviruses RNA core.
Must contain an enzyme called reverse transcriptase.
RNA + reverse transcriptase--DNA—inserts into host cell’s DNA—host cells ribsomes make mRNA—Proteins are part of new viruses

6. Viroids & Prions Viroids: Prions: Naked RNA that can replicate.
Infectious proteins.
Disrupt the cells activities.

7. Polio virus
Influenza Virus
Ebola
Rabies

8. Bacteria Prokaryotic cells. Always single cell. Composed of: Cell wall
Cell membrane
Cytoplasm.
DNA that is a single closed loop
NO membrane bound organelles

9. Plasmids Some bacteria have a secondary genome called a plasmid.
Small self replicating DNA that cause disease or make the bacteria resistant to antibiotics

10. Bacteria Some bacteria have a capsule.
Composed of polysaccharides.
Protects bacteria from WBCs.
Bacteria have short hair like structures called pili for connecting to each other and to hosts.

11. Nonspecific Defenses

12. Nonspecific Defenses Pathogens are disease causing agents.
Resistance is your bodies ability to defend against pathogens.
Your immune system gives you resistance.

13. Identifying Pathogens
Koch’s Postulates
Pathogen must occur in body of organism with the disease.
Pathogen should be isolated and grown in culture.
Inoculated animal should develop the disease.
Same pathogen should be grown in culture.

14. Physical Barriers to Disease
Nonspecific defense.
Sweat, oils, & waxes.
Mucous membranes.
HCL of stomach.

15. Fever Pathogens that attack human body like 98.6 f. best.
Hypothalamus raising temperature of body increases effectiveness of WBC’s.
Decreases effectiveness of pathogen.

16. Proteins Interferons Complement Proteins
Chemical released by cells infected by viruses.
Causes surrounding cells to resist infection.
Complement Proteins
Circulate in your blood and become active when they encounter certain pathogens

17. Inflammatory Response
Inflammatory response occurs when pathogen penetrates the skin.
Nonspecific- any pathogen causes an inflammatory response if your skin is broken

18. Inflammatory Response
Symptoms:
Redness
Heat
Swelling pain

19. Inflammatory Response
What occurs:
Damaged cells release histamines.
Causes increase in permeability.
Causes vasodialation (swelling)
Allows phagocytes to digest and destroy foreign matter.
Phagocytes are drawn towards histamine

20. Non specific Cellular Defense
Neutrophils
Most common phagocyte
Kill pathogens using phagocytosis.
Circulate in blood stream.
Migrate towards site of infection. (chemotaxis)
Move out of the blood stream (emmigration)

21. Non specific Cellular Defense
Macrophages- another type of phagocyte
Stationed in certain tissues.
Destroy by phagocytosis.
Rid the body of debris and damaged cells.

22. Non specific Cellular Defense
Natural Killer Cells
Cytotoxic T Cells
Attack cells which have been infected by pathogen.
Kills cancer cells.
Kills by puncturing cell membrane.

23. Day 3
Immune system and recognition of pathogens

24. How WBCs Recognize Pathogens
All of your cells are marked as “self” by proteins in your cell membrane.
Nonspecific WBCs recognize your proteins.
They leave these cells alone.
Any cell that does not have “self” markers are attacked.

25. Summary of Immune System To Date:
Body has different “lines of defense”.
Barriers
Skin, mucous membranes, secretions.
Non specific defenses.
Macrophages, neutrophils, natural killer cells.
Interferon, compliment proteins.
Specific defenses.

26. RBC of different blood type has antigens
Specific Defenses
If pathogens enter the body, the immune system responds.
Response is to specific pathogens. (Single type)
RBC of different blood type has antigens

27. Immune System Organs Thymus gland Spleen Bone marrow Lymph nodes
Lymphocytes
B cells
T cells (helper, cytotoxic)

28. Immune Response how antigens are 1st recognized by lymphocytes- cell mediated response
Pathogen has proteins (antigens) on its surface.
Macrophages destroy pathogen.
Macrophages present parts of the pathogen (antigen) to helper T cells.
Macrophages release interleukins
Interleukins cause
Cytotoxic Killer T cells to destroy infected cell
Creation of B cells

29. How Antigens are Recognized
Lymphocytes then remember the antigen.
Attack and destroy if in body.
Cell mediated immune response.
Antibody and cell mediated immune response are happening at the same time in the body.

30. Cell Mediated Immune System
Macrophages present portion of pathogen to B Lymphocyte cells.
B cells learn pathogen structure and divide into plasma cells and memory cells
Antibodies are made
Bacteria adhering to T lymphocyte.

32. Antibody Mediated Immune System
Plasma cells produce proteins called antibodies.
Antibodies recognize and attach to pathogen.
Antibodies are Y-shaped proteins.

33. Antibody Mediated Immune System
The two arms of the antibody are identical.
Antibodies match proteins of pathogen.
Actions of antibodies.

34. Antibody Mediated Immune System
Primary response occurs the first time exposure to pathogen occurs.
Secondary response occurs when pathogen invades again.
Faster reaction.
Stronger reaction.
Memory B cells.

35. Immunity & Vaccination
Naturally acquired active immunity.
Your are exposed to pathogen in everyday life.
Naturally acquired passive immunity.
Breast milk.
Mom’s antibodies prior to to birth.
Artificially acquired active immunity.
Vaccination.
Artificially acquired passive immunity.
You are given a shot of antibodies.

36. Brain Pop
Immune System ↑
Bacteria ↑