Immunology: Inflammation: Cellular Events PDF, 2021

Last edited: 8/9/2021 INFLAMMATION: CELLULAR EVENTS Immunology: Inflammation: Cellular Events Medical Editor: Dr. Sofia Suhada M. Uzir OUTLINE I) OVERVIEW – EVENTS IN INFLAMMATION II) REVIEW QUESTIONS III) REFERENCES...

Last edited: 8/9/2021 INFLAMMATION: CELLULAR EVENTS Immunology: Inflammation: Cellular Events Medical Editor: Dr. Sofia Suhada M. Uzir OUTLINE I) OVERVIEW – EVENTS IN INFLAMMATION II) REVIEW QUESTIONS III) REFERENCES I) OVERVIEW – EVENTS IN INFLAMMATION WBCs leave blood and enter tissue spaces → where pathogen is, and this leads to different cellular events including phagocytosis and nonspecific pathogen killing (A) PHAGOCYTOSIS This process is mainly carried out by neutrophils and macrophages Neutrophils and macrophages perform phagocytosis of pathogen taking pathogen into cell → forming a phagosome → this combines with lysosomes (have specific types of hydrolytic enzymes) in cells → forming a phagolysosome Figure 1. Phagocytosis after an injury [Lumen Learning] → lysosomal enzymes break down pathogen (2) Macrophages macromolecules into small pieces (antigens) In macrophages these antigens may be expressed on MHC II molecules on cell surface (1) Neutrophils o These macrophages are referred to as Antigen In neutrophils these antigens are exocytosed into Presenting cells (APCs) → these APCs then interact interstitial fluid and then carried to nearby lymph nodes with T-helper cells Neutrophils also kill these pathogens in the These will later on also go to the nearby lymph nodes phagolysosome via respiratory burst (i) Antigen Presenting cells (APCs) (i) Mechanism o Macrophages o The neutrophils use reactive oxygen species like o Dendritic Cells H202 to make HOCL via an enzyme called o B-cells myeloperoxidase o This HOCL destroys the pathogens but in the process HOCL molecules also destroy neutrophils as well → leading to DNA of neutrophil being released out of cell → This DNA binds to other pathogens in a net like fashion (neutrophil extracellular trap) → this enhances other WBCs to phagocytose that tagged pathogen Figure 2. Inflammatory response showing macrophages and neutrophils acting on pathogens [Biology exams 4 U] INFLAMMATION: CELLULAR EVENTS IMMUNOLOGY: Note #1. 1 of 3  (B) NONSPECIFIC PATHOGEN KILLING (1) Natural killer cells Activation of natural killer cells (i) Through MHC I complex If a viral pathogen infects tissue cells → virus induces abnormal MHC I complex or inhibit MHC I formation o This foreign MHC I or absent MHC I due to viral infection → activates natural killer cells o The activated natural killer cells → release perforins and granzymes which trigger apoptosis of viral infected cells (ii) Via antibody dependent cell mediated cytotoxicity If IgG antibodies made by plasma cells bind viral antigens expressed on MHC I complex → This allows natural killer cells to bind to Fc portion of IgG antibody via their CD-16 protein → This activates the natural killer cells o The activated natural killer cells then release perforins and granzymes which trigger apoptosis of viral infected cells Figure 3. Direct and indirect activation of NK cells [Frontiers in Immunology] 2 of 3 IMMUNOLOGY: Note #1. INFLAMMATION: CELLULAR EVENTS  II) REVIEW QUESTIONS III) REFERENCES Amir Horowitz, Kerstub A. Stegnabb abd Ekeabir M. Riley. Which refers to swelling as a result of inflammation? Activation of natural killer cells during microbial infections. [Digital a. Erythema image] https://internal- b. Edema journal.frontiersin.org/articles/10.3389/fimmu.2011.00088/full 2012. c. Granuloma Biology Exams 4 U [Digital image] https://www.biologyexams4u.com/2012/11/immunology- d. Vasodilation inflammatory-response.html Lumen Microbiology Course [Digital image] Which type of inflammation occurs at the site of an https://courses.lumenlearning.com/microbiology/chapter/inflammatio injury or infection? n-and-fever/ a. Acute Cara Splash. Inflammation Quiz. 2021 b. Chronic https://www.funtrivia.com/playquiz/quiz28640520ca160.html Le T, Bhushan V, Sochat M, Chavda Y, Zureick A. First Aid for c. Endogenous the USMLE Step 1 2018. New York, NY: McGraw-Hill Medical; 2017 d. Exogenous Marieb EN, Hoehn K. Anatomy & Physiology. Hoboken, NJ: Pearson; 2020. Which of these processes is NOT one of the cellular Boron WF, Boulpaep EL. Medical Physiology.; 2017. events involved in the inflammatory process? Urry LA, Cain ML, Wasserman SA, Minorsky PV, Orr RB, Campbell NA. Campbell Biology. New York, NY: Pearson; 2020. a. Margination Jameson JL, Fauci AS, Kasper DL, Hauser SL, Longo DL, b. Diapedesis Loscalzo J. Harrison's Principles of Internal Medicine. New York c. Selection etc.: McGraw-Hill Education; 2018. d. Rolling lberts B, Johnson A, Lewis J, Raff M, Roberts K, Walter P. Molecular Biology of the Cell. New York, NY: Garland Science; Which of the following is NOT and antigen 2002 Murphy K, Weaver C. Janeway's Immunobiology. Garland presenting cells? Science; 2016 a. Macrophages Doan T, Melvold R, Viselli S, Waltenbaugh C. Immunology. b. Dendritic Cells Lippincott Williams & Wilkins; 2012 Levinson W. Review of Medical Microbiology and Immunology. c. B-Cells Lange; 2012 d. T-cells Which of the following processes is not a step in phagocytosis? a. Recognition b. Adhesion c. Engulfment d. Degradation What is the name of the enzyme involve in neutrophil’s reaction during an inflammation? a. Myroxomes b. Myeloperoxidase c. Perforins d. Granzymes Which statement is incorrect regarding macrophages? a. It has no role during an inflammatory response b. It may be expressed on MHC II molecules c. It is considered as an APCs d. It interacts with T-helper cells during an inflammation Regarding nonspecific pathogen killing, which is true? a. The virus induces abnormal MHC II complex or inhibit MHC II formation b. It has no role in antibody dependent cell mediated cytotoxicity c. Perforins and granzymes are released d. It inactivates natural killer cells Regarding perforins, which is true? a. It is activated by neutrophils b. It triggers apoptosis of viral infected cells c. It triggers hemolysis of blood cells d. It is phagocytosed by the macrophages Which of the following statements regarding IgG antibodies are correct? a. It helps release myeloperoxidase enzymes b. It helps phagocytosis of viral infected cells through the release of neutrophils c. It is made by plasma cells d. It helps in regulation of body temperature when inflammation occurs CHECK YOUR ANSWERS INFLAMMATION: CELLULAR EVENTS IMMUNOLOGY: Note #1. 3 of 3