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Understanding Immunity to Microbes

Explore the immune system's defense against infectious microbes, including innate and adaptive immunity responses to extracellular and intracellular pathogens. Learn about immune evasion mechanisms, cell-mediated immunity, and examples of immune responses to various microorganisms.

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Understanding Immunity to Microbes

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  1. Immunity to Microbes DiniAgustina MikrobiologiFKUJ 2017

  2. Immunity • Means  Protection from the disease and, more specifically, infectious disease • Immune system defense against infectious microbes Mediated by Innate immunity early reactions Adaptive immunity later respons

  3. Immune System Microbe Adaptive immunity Innate immunity B lymphocytes Antibodies Epithelialbarriers T lymphocytes Effector T cells Phagocytes Complement NK cells Hours Days 0 6 12 1 3 5 Time after infection

  4. Types of pathogenic microorganism

  5. Extracellular Bacteria

  6. Capable of replicating outside host cells, for example in the circulation, in connective tissues and in tissues spaces such as the airways and intestinal lumens. • Two principal mechanisms cause the diseases : • induce inflammation • produce toxin • Innate immunity  complement activation, phagocytosis, inflammatory response • Adaptive immunity  humoral immunity: eliminate the microbes and neutralize their toxins

  7. Innate immunity to extracellular microbes: Phagocytosis

  8. Phagocytosis of Streptococcus pyogenes by a macrophage. CELLS alive! Pathogens may resist phagocytosis by: Evading phagocytes by growing in regions of the body which are not accessible to them Avoiding engulfment by phagocytes after contact Being able to kill phagocytes either before or after engulfment Being able to survive inside of phagocytes (or other types of cells) and to persist as intracellular parasites Kenneth Todar, Ph.D.

  9. Innate immunity to extracellular microbes: Complement Activation

  10. Adaptive immunity to extracellular microbes

  11. Immune evasion by extracelluler bacteria

  12. Intracellular Bacteria

  13. Characteristic : ability to survive and even replicatewithin phagocytes • Innateimmunity may control bacterial growth, • adaptive immunity required elimination of bacteria • Innate immune response : phagocytes and natural killer (NK) cells • intracellular bacteria activate NK cells : • Directly • Stimulating macrophage production of IL-12 • NK cells produce IFN Ý actvates macrophages • Adaptive immune response : cell-mediated immunity • consists of two types of reactions : • Macrophage activation by the Tcells-derived signals CD40 ligand and IFN Ý  killing of phagocytosed microbes • Cytolytic T lymphocytes  lysis of infected cells

  14. Innate immunity to intracellularmicrobes

  15. Adaptive immunity to intracellular microbes

  16. Immune evasion by intracelluler bacteria

  17. Fungi

  18. Innate immunity : neutrophils and macrophages • Adaptive immunity : cell-mediated immunity Example: • Histoplasmacapsulatum: cellular mechanisms of intracellular bacteria • Cryptococcus neoformans: cooperate between CD4+ and CD8+ • Candida : cell-mediated immunity

  19. Viruses

  20. Innate immunity : inhibition of infection by type I IFNand NK cells (by killing injured or/and infected cell) • Adaptive immunity : cell-mediated immunity • Antibodies • Block virus binding and entry into host cell (Neutralization) • Act as opsonin to increase phagocytic killing by phagocyte • CTL’s eliminate the infection by killing infected cells

  21. Immunity to viruses

  22. Immune evasion by viruses: Antigenik drift vs Antigenik shift

  23. Inhibition of virus antigen presentation to CTL

  24. Parasites (helminth)

  25. Innate immunity to parasites: EOSINOPHIL

  26. Adaptive immunity to parasites: Th2 FUNCTION

  27. Immune evasion by parasites

  28. Latihan soal

  29. Seorangremajaberusia 21 tahundatangkerumahsakitswastadengankeluhannyeripinggangkanan, setelahdilakukanpemeriksaanlengkap, pemudatersebutdidiagnosa (Glomerulonephritis Akut) GNA. Dari anamnesaternyatadidapatkanriwayatseringmenderitanyeritenggoroksejakkecil.

  30. Termasukdalamjenismikroorganismeapakahagenpenyakittersebut … • Ekstraselulermikroba • Intraselulermikroba • Multiselulermikroba • Fungi • Virus

  31. Mekanismepatogenesitaspadamikroorganismetersebutadalah … • Aktivasimakrofag • Inflamasiakut yang diinduksiolehdindingsel • Inflamasiakut yang diinduksiolehtoksin • Inflamasi granuloma • Menghambatsintesis protein

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