1. Nonspecific Immunity

2. What is non specific immunity? Protects regardless of pathogen Includes first and second line of defense –We’ll discuss third line in another lecture!

3. First line of defense

4. What is the first line of defense? Physical barriers Chemical barriers Normal Microbiota

5. What are physical barriers? Skin –Epidermis Many cells packed tightly Keratin Arid Benign microbes sloughing –Dermis Infections most likely from –Subcutaneous staphylococci

6. What are chemical barriers? Lysozyme Mucous membranes Lacrimal apparatus Saliva Mucociliary escalator Epiglottis Urine Vaginal secretions Lactic acid mantle

7. Normal Microbiota Microbial antagonism/competitive exclusion: Normal microbiota compete with pathogens. –Candida albicans –E.coli –Salmonella –Shigella

8. Second line of defense

9. What constitutes the second line of defense? Phagocytosis Inflammation Complement Interferons

10. What are phagocytes? Literally means ___________ All are leukocytes Neutrophils Leukocytes Monocytes –Macrophages Eosinophils Basophils

11. How do phagocytes work? Adherence Phagosome Phagolysosome

12. Does phagocytosis always work? Nope! Adherence inhibition –Streptococcus pyogenes M protein –Capsules also H pylori, Streptococcus pneumoniae Ingested but still alive –Staphylococcus leukocidins –Streptococcus streptolysin Staphylococcus

13. Does phagocytosis always work? Mycobacterium tuberculosis, HIV, Chlamydia, Plasmodium –Prevents fusion and acidification of enzymes –Multiply within phagocyte Chlamydia inclusion on pap smear cell

14. How do leukocytes get to a wound? Diapedesis Chemotaxis

15. What about inflammation? Pain Redness Swelling Heat Acute inflammation –Boil: S. aureus Chronic inflammation –M. tuberculosis

16. What is fever? Pyrogens –Exogenous Some viruses, endotoxins –Endogenous Interleukin I Inhibits pathogens Reduces iron availability Stimulates immune response

17. The Complement System Serum proteins activated in a cascade. Figure 16.9

18. Effects of Complement Activation Opsonization or immune adherence: Enhanced phagocytosis. Membrane attack complex: Cytolysis. Attract phagocytes. Figure 16.10

19. Effects of Complement Activation Figure 16.11

20. What happens with complement? –20 subunits –Cascade reaction –Classic pathway Binding to mannan stimulates –AnimationAnimation

21. What happens with complement? –20 subunits –Cascade reaction –Lectin pathway Binding to mannan stimulates –AnimationAnimation

22. What are interferons? Antiviral –Induce antiviral protein production –Causes neutrophils and macrophages to phagocytize bacteria. –animationanimation