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75 Cards in this Set
- Front
- Back
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3 types of lymphocytes, what % of circulating lymphs is each:
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B cells - 15%
T cells - 70% NK cells - 15% |
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Origin of lymphocytes, site of maturations?
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Bone marrow origin
B cells mature in BM T cells mature in thymus |
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2 sites of Bcell maturation other than just the bone marrow:
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-Germinal centers of lymph nodes
-Lymphoid follicles of spleen |
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Characteristic feature of Bcells:
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Surface immunoglobulin
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2 sites of Tcell residence other than thymus:
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-Medulla/paracortex of lymph nodes
-Periarteriolar sheaths of spleen |
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2 subtypes of Tcells:
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Cd4+ Thelper cells
CD8+ Tkiller cells |
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Normal ratio of CD4:CD8 cells:
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2:1 - 60% vs 30%
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Disease in which CD4/CD8 ratio is dramatically altered:
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AIDS
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NK cells are aka:
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LGLs - large granular lymphoyctes
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Functions of NK cells:
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Kill tumor cells, fungi, virus-altered cells.
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What is NOT required for NK cells killing of tumor cells, fungi, virus-altered cells?
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No antibody necessary; nonspecific; this is innate.
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What type of killing by NK cells does involve antibody?
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ADCC - ab dependent cell-mediated cytotoxicity
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Macrophages:
-derivatives of what -members of what |
Derived from peripher MONOCYTES
Members of MPS - mononuclear phagocyte system |
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4 major secretions of macrophages:
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IL-1
Acid hydrolases Proteases Prostaglandins |
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2 major functions of Macrophages:
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-Process/present Ag to Thelpers
-Participate in DTH - delayed type hypersensitivity |
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So which type of hypersensitivity are macrophages involved in?
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Class 4 - DTH
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What HLA class is on Macrophages?
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Class II HLA
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2 other important cells of the immune system in addition to lymphocytes and macrophages:
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-Dendritic cells of lymphoid tissue
-Langerhans cells of the skin |
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2 Hallmark features of dendritic cells:
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-Cytoplasmic dendritic processes
-Lots of HLA class II! |
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What is Class II so important for?
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Allows cells to be APC's
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How do Dendritic cells compare to Macrophages?
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-Less phagocytic
-Both are APCs |
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Ultrastructural feature to remember about Langerhan's cells of the skin:
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Birbeck granules! Tennis racket-shaped structures in the cytoplasm
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What cells are Langerhan's cells like? How?
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Dendritic cells of lymphoid tissue - both express HLA class II and are APCs
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What are the effector molecules of the lymphoid cells?
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Cytokines
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Sources of IL1 (most prominent)
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-Monocytes
-Macrophages |
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Major functions of IL1
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Stimulates Tcell proliferation and IL2 production, acute phase reaction, etc.
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IL2 sources:
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Macrophages, T0 AND Th1 cells, NK cells
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Functions of IL-2
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-Autostimulation of proliferation and differentiation into Th1 cells
-Activates monocytes |
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Source of IL-3,4,5
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Tcells
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Major function of IL-3:
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Growth factor for tissue Mast Cells and Hematopoietic Stem Cells
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Major function of IL-4:
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Growth of B/Tcells; enhanced expression of HLA class II
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Major function of IL-5:
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End stage maturation of Bcells into Plasma cells
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Sources of Il-6:
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Monocytes/Tcells
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2 major functions of IL-6:
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-Inhibits Fibroblast growth
-Promotes T/Bcell maturation |
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What are the interferon's functions in general?
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Antiviral
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Major sources of IFN-alpha:
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Bcells and Macrophages
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Major sources of IFN-gamma
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Tcells and NK cells
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Function of IFN-alpha
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Antiviral
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Function of IFN-y
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Activates macrophages, enhances expression of HLA Class II MHC
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Major sources of TNF-alpha/beta
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Tcells, NK cells, Macrophages
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Functions of TNF-alpha/beta:
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-stimulates Tcell proliferation
-stimulates IL2 production -Acute phase reaction - fever, activates EC's to increase adhesin expression, etc. |
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2 cytokines that play a major role in rheumatoid arthritis:
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IL1 and TNF-alpha
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Which cytokine promotes Th2 CD4+ differentiation and IgE synthesis from B cells?
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IL-4
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What does IL-4 inhibit?
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Th1 CD4+ cells
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Infection that increases IL4 and decreases Th1 inflammation?
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Trichuris suis - parasitic
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Which cytokine stimulates Bcell growth, immunoglobulin secretion from Plasma cells, and Eosinophil maturation?
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IL-5
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Which cytokine activates NK cells and promotes generation of Th1 CD4+ Tcells?
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IL-12
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What are the 2 main pathways of the COMPLEMENT system?
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-Classical
-Alternate |
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What is the Classical pathway stimulated by?
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ANTIGEN-ANTIBODY COMPLEXES
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What is the Alternate pathway stimulated by?
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NONIMMUNOLOGIC STIMULI
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What are HLA antigens?
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Human leukocyte antigens
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What are the genes that encode for HLA antigens called?
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Histocompatibility genes
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What is the chromosome that houses the HLA genes? What is this region called?
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Ch' 6 - MHC, major histocompatibility complex.
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So HLA-A,B,C refer to what MHC?
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MHC I
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What cells express MHC I?
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All nucleated cells
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What is HLA-DP, DQ, DR?
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MHC II
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What cells express MHC II?
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APC's - antigen presenting cells; Macrophages, dendritic cells, langerhan cells, B cells, and some T cells.
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What important pathologic process are Class I HLA antigens involved in?
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Tissue graft rejection
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Which is the most important antigen for tissue graft rejection and typing?
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HLA-B
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What is the most important HLA association with disease to remember?
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HLA-B27 and Ankylosing spondylitis (90% association)
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What 3 entities make up Reiter syndrome?
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-Uveitis
-Conjunctivitis -Arthritis |
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What is the term for adverse reactions caused by immune mechanisms?
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Hypersensitivity reactions
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Which HSN reactions require Ab production by plasma cells?
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1,2,3
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What are Type IV HSN reactions mediated by?
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Tcells and macrophages
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What are the steps in Type I hsn reactions?
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1. Exposure to allergen
2. IgE production from B cells (via IL-4); coats Masts/Basophs 3. Subsequent Exposure - Ag binds sensitized cells, degran 4. Histamine release increases vascular permeability 5. Late phase reaction shows neutrophils/eosinophils (IL5) |
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What are 3 clinical examples of Type I hypersensitivity?
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-Allergy/atopy - rhinitis (hay fever), asthma, urticaria/hives
-Anaphylactic shock -Angioedema |
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4 characteristic symptoms of Anaphylaxis:
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HLBS
-Hives -Laryngeal edema -Bronchospasm -Shock |
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What is Angioedema?
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Acute edema of cutaneous and mucosal structures of face/lips
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Is Angioedema in type I HSN the same thing as Hereditary angioedema?
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NO
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What is Hereditary angioedema caused by?
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C1 esterase inhibitor!
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Result of lack of C1 esterase inhibitor:
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Overactive complement - low serum C3/C4 but NOT type I HSN.
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So type I HSN is aka:
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Immediate
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What is Type II HSN aka?
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Antibody-mediated, Cytotoxic.
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What is Type III HSN aka?
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Immune complex mediated
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What is the main difference between Type II and III HSN?
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Type II - Ab is fixed to a surface; intrinsic component of the target cell.
Type III - immune complex is floating; not intrinsic component of the target cell. |
