The Fish Immune System

1. The Fish Immune System

2. What does the immune system do? War Fish vs. Everything

3. Enemy Pathogens Front Lines Home

4. Foreign Vs. Self The good bits that are supposed to be there The bad stuff: bacteria, fungi, viruses, cancer

5. Planes, Ships Tanks, and Ammunition • (Planes, Ships, Tanks) White blood cells • Lymphocytes • Neutrophils • Macrophages • Eosinophils • (Mines and Booby Traps) Blood Proteins • Complement • Lysozyme • Antibodies • Many more

6. Mines

7. Inside the Liver

8. Complement “Gee Adjwoa, I really like the bling on your cell phone”

9. Complement A defensive protein made by the liver and secreted into the blood. Primary target: Gram negative bacteria.

10. Gram Neg Gram Pos Membrane bi-layer Peptidoglycan layer

11. Complement Complement molecules begin to assemble a complex on the membrane of Gram (-) bacteria Complement forms a channel through the cell wall

12. Complement Recognizes Gram (-) bacteria

13. Lysozyme

14. Lysozyme L • Dissolves Gram (+) bacterial cell walls • Found in • Blood • Mucus • Eggs

15. Other Mines…. • Proteases: Damage pathogens • Protease inhibitors: Block invasion • Histones: Antibacterial • Iron-sequestering proteins: Starve bacteria. • Lactoferrin disrupts outer membrane on Gram negs (helps lysozyme) • C-reactive protein: Recognizes bacteria, triggers complement

16. Mines • Blood Proteins • Always there and ready • Work in complexes • Identify foreigners • Destroy or disable

17. Tanks and Planes

18. Lymphocyte Antibodies

19. Antibodies: Blood proteins that bind to foreigners. Made by lymphocytes

20. Antibody Anatomy Variable Binding Region Antibody Molecule

21. Antibodies bind all over a Rhabdovirus and block it from infecting a cell.

22. Antibodies recognize foreign antigens on an “ich” parasite and mark it for destruction.

23. Antibodies Designate Targets

25. What about lymphocytes that recognize "self"?

26. The thymus kills the self-reacting thymocytes

27. Location of the Thymus in a Grass Carp

28. Life and Death in the Thymus “Lymphocyte Must Die” Thymocyte Self Antigen

29. Two Kinds of Lymphocytes

30. B

31. More Identical B-Cells Antigen Memory Cell B-Cell Plasma cell

32. Memory cells: The Lymphocyte Barracks

33. T

34. T-Lymphocyte Cell Killing Chemicals from the T-cell Viral Proteins (antigens) Virus-infected cell

35. More Identical T-Cells Antigen Memory Cell T-Cell T

36. Memory cells: The Lymphocyte Barracks

37. B-cells: Secrete antibodies that bind to antigens on foreign things T-cells: Attach to and kill infected cells with foreign antigens

38. Lymphology • Self reacting lymphocytes weeded out by thymus • Lymphocytes proven useful proliferate to make more highly trained fighter pilots (B&T), and… • Copies of useful lymphocytes are put in the barracks in case the same enemy attacks again.

39. Macrophages “Big Eaters"

40. Macrophage USS Macrophage

41. Macrophages

44. Macrophages as Big Eaters

45. Macrophage Diets Bacterial Cell Walls Cell with Compliment Cells with Antibody Flags

46. Vacuoles containing bleach (brown) and peroxide (green) fuse with a vacuole containing a live bacterium

47. More Tricks: Macrophages Searching out Foreigners

48. A roving macrophage detects a parasite trying to hide among a layer of fish cells. Normal cells with MHC “locks” Parasite with fake lock

49. Macrophages Even Run a School for Lymphocytes

50. 2 1 Macrophage Macrophage eating a bacterium 3 4 Macrophage using bacterial bits to educate lymphocytes. Macrophage digesting a bacterium