1	CLSC320 Principles of Immunology Fundamental Concepts in Immunology Program for Clinical Laboratory Science Unit - 04 Soluble Components of The Immune System
2	Unit – 04 Guidlines Reading assignment: Pages 78 - 89 of textbook Learning objectives: Those listed on page 79 of textbook Key terms: Those listed on page 79 of textbook
3	Definition of Soluble Components A diverse group of soluble molecules secreted by a variety of cells and include: Cytokines e Immunoglobulins e Complement components
4	Cytokines - 1 Definition: Cytokines are a group of proteins that are produced by different cell populations and affect different target cells. Three functional groups of cytokines: eMediators and regulators of non-specific immune responses. Cytokine Produced by Target cell effects IL-1 IL-12 TNF" IFN-( macrophages T-cells & B-cells stimulate cell division all APC=s Th1 and NK cells enhances other IL=s macrophages tumors inflammatory mediator T8+, NK, Th1 NK cells cell activation Cytokines
5	Cytokines - 2 Three functional groups of cytokines: cont=d eMediators and regulators of specific immune responses. Cytokine Produced by Target cell effects IL-2 IL-4 IL-5 IFN-( T-cells T & NK-cells proliferation of antigen- specific cells & other immature cells T4 cells B-cells antibody switching to IgE T-cells B-cells growth & differentiation of eosinophils T8, Th1 & NK most cells B-cell activation, T-cell production of MHC-I, Th1 production of IL-2 and IL-2R Cytokines
6	Cytokines - 3 Three functional groups of cytokines: cont=d eRegulators of hematopoiesis. Cytokine Produced by Target cell effects IL-3 IL-7 GM-CSF M-CSF T-cells stem cells growth & differentiation of blood cells Stroma cells lymphocytes generate pre-T & pre-B cells macrophages myeloid stem growth & differentiation of myeloid line fibroblasts, macrophages monocytes stimulate production of monocytes & macrophages Cytokines
7	Cytokine – IL-2 Th1 NK IL-2 B-cells proliferation differentiation enhanced Ig production T-cells proliferation lymphokine production enhanced cytotoxic activity NK-cells activation enhanced cytotoxic activity macrophages increased cytotoxic activity enhanced IL-1 secretion Cytokines
8	Cytokine – IL-3 T-cells macrophage NK IL-3 B-cells enhanced Ig production mast-cells differentiation stem-cells growth of all stem cell populations macrophages increased cytotoxic activity enhanced phagocytic activity Cytokines
9	Cytokine – IL-4 Th2-cells IL-4 B-cells enhanced proliferation enhanced CD23 & MHC-II expression IgG1, IgE & IgA secretion T-cells enhanced proliferation increased cytotoxic activity giant cell formation stem-cells growth of all stem cell populations macrophages increased cytotoxic activity enhanced antigen presenting enhanced MHC presenting Cytokines
10	Cytokine – IL-5 activated Th2 cells IL-5 B-cells increased proliferation IgM, IgA & IgG secretion increased expression of IL-2R T-cells enhanced cytotoxicity eosinophils enhanced differentiation enhanced chemotaxis Cytokines
11	Cytokine – IL-7 stromal cells of bone marrow & thymus IL-7 pre-B-cells increased proliferation thymocytes increased proliferation increased T8 cells T-cells increased proliferation increased expression of IL-2, IL-2R & CD71 lymphoid stem cells control of proliferation Cytokines
12	Cytokine – IL-10 Th2-cells macrophage B-cells IL-10 B-cells enhanced MHC-II expression enhanced growth mast-cells proliferation macrophages suppressed production of IL-1, IL-12, TNF", MHC-II suppresses Th1 cell function Cytokines
13	Cytokine - IFN-( Th1-cells NK-cells IFN-( B-cells enhanced IgG2 decreased CD23, IgE, & IgG1 counteracts IL-4 NK-cells increased activity T-cells induce IL-2 & IL2R enhanced T suppressor activity enhanced cytotoxicity macrophages enhanced production of TNF", MHC-II enhanced antimicrobial & antitumor activity viral infected cells depressed viral growth Cytokines
14	Cytokine - TNF-a macrophages TNF-" All cells with TNF receptors increased cytotoxicity and antiviral activity increased fibroblasts and thymocytes production stimulates IL-1, IL-6, CD11b/CD18, & MHC-II inflammatory mediator regulates growth of normal cells induces weight loss Cytokines
15	Definition of Antibody Antibodies Definition: Antibodies (immunoglobulins) are a group of proteins (globulins) found on B-cells and in body fluids. Two functional groups of antibodies: eB-cell surface bound antibodies: eFree (soluble) antibodies in fluids: Usecreted by B lymphocytes Uact as receptors Uact as cell markers Usecreted by plasma cells Ubind to antigen with same specificity Cytokines
16	Basic Antibody Structure Cytokines Fab portion Fc portion Fab = fragment antigen binding (where antigen binds) Fc = fragment crystallizable (responsible for biological functions) light chains 2 kappa (6) or 2 lambda (8) heavy chains 2 ( or 2 " or 2 : or 2 * or 2 , IgG IgA IgM IgD IgE carbohydrates
17	Serum Protein Electrophoresis Cytokines NORMAL ELECTROPHORESIS PATTERN DIRECTION OF MIGRATION ( $ "₂ "₁ Albumin
18	Antibody Functions Function: ebinding of antigen with same specificity via Fab portion ebind to various immune cells via Fc portion eserve as opsonins and thus enhance phagocytosis NOTE:opsonins are molecules that attach to an organism and promote or enhance phagocytosis. Examples include: Uantibodies Ucomplement components Cytokines
19	Definition of Complement System Definition: a group of plasma and membrane proteins that, upon activation, produce certain effects associated with the humoral immune responses. Humoral immune responses: eimmune adherance eosponization echemotaxis ekinin activation ecell lysis einflammation (anaphylatoxis) Cytokines
20	Complement Structure Structure: efound in the $1 and $2 globulin region on protein electrophoretic isolation enormally seen in the inactive form (zymogens) in plasma esystem may become activate through two pathways: Uclassical pathway Ualternative pathway ezymogens are converted to proteases by proteolysis eactivation process is a Acascade@ type reaction where one protease activates a zymogen and the resulting protease activates another zymogen, etc. Cytokines
21	OSF-6 Complement System On pages 84 - 86AOne Step Further@ presents a more in-depth discussion of the complement activation. This presentation is contained on a separate slide presentation called A One Step Further #6" The student may call up the slide program OSF-6 later or click on the arrow below to view slides now. Cytokines
22	Destruction of Complement Destruction of complement in vitro: ecomplement components are heat labile (inactivated by heat) Uheating to 56^oC for 30 minutes ecomplement components may also be inactivated by anticoagulants UEDTA ecomplement components may also be inactivated by chemicals Ucholine chloride Cytokines
23	Function of Complement Functions of complement: eBiological effects Ubacterial opsonization mC3b binds to bacterial C3b receptor Uchemotaxis mC5a released during inflammatory response acts as an attractant for: -neutrophils -macrophages eCell lysis Uantibodies bind to cell surface Ucomplement activated via classical pathway Umembrane attack complex (MAC) formed Ucell destroyed via osmotic inbalance with H₂O entering cell Cytokines
24	Complement Nomenclature Nomenclature of complement system: eClassical pathway & MAC Uidentified by numbers and letters: mC3i, C5i, etc. designate the zymogen (inactive form) __ __ mC3a, C5b, etc. designate the protease (active form) mduring proteolysis to form proteases fragments are split off: -large fragment called Aa@ (i.e. C3a) -small fragment called Ab@ (i.e. C3b) eAlternative pathway & MAC Uidentified by letters preceded by factor: mfactor B, factor H, etc. Cytokines
25	Soluble Components Press the ESC key to end program
26	One Step Further Complement Activation OSF - 6 Pages 84 - 86 Click here to return to main program
27	OSF - Pathways Two enzymatic pathways available: eClassical pathway eAlternative pathway Žfirst one discovered Žactivated by immune complexes Žactivated primarily by polysaccharide structures microbial cell walls is an example Two enzymatic pathways join at: eClevage of C5 which results in: Žformation of the Membrane Attack Complex (MAC) this results in lysis of cell
28	Classic Pathway Activation ethe sequence of activation is: Immune complex \ C1q of C1 complex \ C4 - C4a \ C4b \ C2 - C2a \ C2b C4b \ C2b - C3 convertase C3 convertase \ C3 - C3b C3b \ C3 convertase - C5 convertase C5 convertase \ C5 - C5b C5b \ C6 \ C7 \ C8 \ C9 MAC cell lysis
29	Alternative Pathway Activation ethe sequence of activation is: C3 - C3b (C3b is found normally in the blood due to hydrolysis of C3) C3b - binds to microbial surface C3b \ Factor D \ Factor B - C3 convertase C3 convertase \ C3 - C3b C3b \ C3 convertase - C5 convertase C5 convertase \ C5 - C5b C5b \ C6 \ \ \ C7 C8 C9 MAC cell lysis
30	Regulation of Pathways eC1 INH eFactor I eFactor H eC4bp Žinhibits C1 binding with immune complex Žinhibits C3b Žinhibits C3 convertase formation Žinhibits C3b + Factor B & Factor D interaction Žinhibits C3 convertase formation Žbinds with C4 Žinhibits C3 convertase formation
31	Complement Activation - End Click here to return to main program