bohomolets microbiology lecture #10
DESCRIPTION
By Ms. Kostiuk from Microbiology departmentTRANSCRIPT
Immunology Immunology
Immune system of organism. Immune system of organism. Antigens Antigens
Features of immune system Features of immune system
Situated in different parts of bodySituated in different parts of bodyRapid regeneration Rapid regeneration Circulation of immune cells in the Circulation of immune cells in the
organism organism Possibility to “learn” Possibility to “learn” Possibility to form a lasting memory Possibility to form a lasting memory
General components of immune General components of immune systemsystem
Immune system consist of:
Central organs:
Thymus
Red marrow bone
Peripheral organs
Spleen
Tonsils
Network of lymph nodes
Lymphatic of intestine
Appendix
Red marrow bone Red marrow bone
Function:
Production of blood cells (hemopoesis)
Maturation of B cells
The thymus glandThe thymus gland
Functions:
Differentiation and maturation of T-lymphocytes
Synthesis of hormones (thymosin, thymolin) that influence to lymphocytes in blood stream.
Lymph node Lymph node
Contain T-lymphocytes and B-lymphocytes
Functions:
filtration of particulate materials (microbes) and contribution of lymphocytes to the lymph as it passes through.
Spleen Spleen
Functions:
Phagocytosis of foreign matter
Immune reactions against bacteria
Removes and breaks down worn erythrocytes
Blood cell development (1)Blood cell development (1)
Blood cell development (2)Blood cell development (2)
Major circulating blood cells of the Major circulating blood cells of the bloodstream bloodstream
Dispedesis and chemotaxis of Dispedesis and chemotaxis of leukocytesleukocytes
Major stages in the development of B Major stages in the development of B and T cellsand T cells
Maturation of lymphocytesMaturation of lymphocytes
Parts of specific immunityParts of specific immunityThe humoral immune system involves the antibodies that are dissolved in the body fluids such as the blood, lymph, and mucus secretions
The cell-mediated immune system involves lymphocytes known as T cells, they act directly on other cells. It is most effective against intracellular pathogens and eukaryotic agents
Contrasting properties of B-cell and T-Contrasting properties of B-cell and T-cell linescell lines
B cellsB cells T cellsT cellsSite of maturationSite of maturation Bone marrowBone marrow ThymusThymus
Nature of surface Nature of surface markersmarkers
Immunoglobulin Immunoglobulin Several CD receptors Several CD receptors
Texture of surface Texture of surface Rough Rough Smoother Smoother
Circulation in blood Circulation in blood Low numberLow number High numbersHigh numbers
Distribution in Distribution in lymphatic organslymphatic organs
Cortex Cortex
(in follicles)(in follicles)
Paracortical (interior to the Paracortical (interior to the follicles)follicles)
Product of antigenic Product of antigenic stimulation stimulation
Plasma cells and Plasma cells and memory cellsmemory cells
Sensitized T-lymphocytes Sensitized T-lymphocytes of several types and of several types and memory cellsmemory cells
General functionsGeneral functions Production of Production of antibodies antibodies
Cell function depends on Cell function depends on type of T-lymphocytes type of T-lymphocytes subpopulationsubpopulation
Micrograph of T lymphocytes Micrograph of T lymphocytes
Light micrograph Scanning electron micrograph
Markers of maturated human Markers of maturated human T lymphocytesT lymphocytes
T-lymphocyte (subsets)T-lymphocyte (subsets) Markers (receptor) on Markers (receptor) on the cell surface the cell surface
Every T-lymphocyte Every T-lymphocyte CD2CD2 (common marker) (common marker)
T-helpersT-helpers CD4,CD4, CD3, CD28 CD3, CD28
Cytotoxic (killer) T-cellsCytotoxic (killer) T-cells CD8CD8, CD5, CD3, CD28, CD5, CD3, CD28
T-suppressorsT-suppressors CD8CD8, CD5, CD5
Delayed hypersensitivity cellsDelayed hypersensitivity cells CD4CD4
Naïve T cellNaïve T cell CD45RACD45RA
Memory T cellsMemory T cells CD45ROCD45RO, CD3, CD3
Characteristics of subsets of T cellsCharacteristics of subsets of T cells
Subset Subset Functions Functions T helper cells T helper cells ((Th, T4Th, T4))
Assist B cells in recognition of antigen; assist other Assist B cells in recognition of antigen; assist other subsets of T cells in recognition and reaction to Agsubsets of T cells in recognition and reaction to Ag
T suppressor T suppressor cells (cells (Ts, T8Ts, T8))
Regulate immune reactions; cells limit the extent of Regulate immune reactions; cells limit the extent of antibody production; block some T-cell activityantibody production; block some T-cell activity
Cytotoxic (killer) Cytotoxic (killer) cells (cells (Tc, TkTc, Tk))
Destroy a target foreign cell by lysis; important in Destroy a target foreign cell by lysis; important in destruction of complex microbes, cancer cells, virus-destruction of complex microbes, cancer cells, virus-infected cells, graft rejection; allergyinfected cells, graft rejection; allergy
Delayed Delayed hypersensitivity hypersensitivity cells (cells (Td, TdthTd, Tdth))
Responsible for allergic occurring several hours or Responsible for allergic occurring several hours or days after contact with Ag; skin reaction as in days after contact with Ag; skin reaction as in tuberculosis testtuberculosis test
Memory T cellsMemory T cells Develop from T-helpers and T-killers. Remain Develop from T-helpers and T-killers. Remain following an infection and are ready to mount a following an infection and are ready to mount a immune response more rapidlyimmune response more rapidly
Antigen presentation to helper T cell. Antigen presentation to helper T cell. Cooperation of T helper and B cellCooperation of T helper and B cell
T helper
T helper
B cell
MO
MO Antigen
macrophage
MHC II
Stages of cell-mediated cytotoxicity and the Stages of cell-mediated cytotoxicity and the action of lymphotoxins on virus-infected cellsaction of lymphotoxins on virus-infected cells
Cancer cell is attacked by Cancer cell is attacked by killer T cellskiller T cells
T lymphocytes Cancer cell
The third line of defense The third line of defense
The third line of defense is specific immune factors
(antibodies and T-lymphocytes)
Features of innate and acquired Features of innate and acquired immunityimmunity
Feature Feature Innate Innate Acquired Acquired Antigen-dependent Antigen-dependent specificity specificity
Yes Yes Yes Yes
Immunologic Immunologic memory memory
No No Yes Yes
((enhancing during enhancing during repeated contact with repeated contact with
antigenantigen))
Dependence on Dependence on В- В- andand Т- Т-lymphocytes lymphocytes
No No Yes Yes
Cell-effectors Cell-effectors Phagocytes, basophiles, Phagocytes, basophiles, eosinophils, natural killer eosinophils, natural killer cellscells,, mastocytesmastocytes
Т- і В- Т- і В- lymphocytes lymphocytes
Humoral effectors Humoral effectors Complement, cytokines, Complement, cytokines, interferons, interferons,
Antibodies Antibodies
Types of acquired immunity Types of acquired immunity
Acquired immunity
Natural Artificial
Active Passive Active Passive
Features of acquired immunityFeatures of acquired immunity
Type Type PropertiesProperties
Naturally acquire Naturally acquire activeactive
Antibodies and specialized lymphocytes acquired Antibodies and specialized lymphocytes acquired after natural exposure to a foreign agent (past after natural exposure to a foreign agent (past infectious immunity). Long lasting, specificinfectious immunity). Long lasting, specific
Naturally acquire Naturally acquire passivepassive
Transfer of antibody to agent from mother to fetus Transfer of antibody to agent from mother to fetus through the placenta (IgG) or with breast milk (IgA). through the placenta (IgG) or with breast milk (IgA). Temporary Temporary
Artificially Artificially acquired activeacquired active
Acquired following immunization, for example with Acquired following immunization, for example with poliovirus vaccine (past vaccine immunity) ; long-poliovirus vaccine (past vaccine immunity) ; long-lasting, specificlasting, specific
Artificially Artificially acquired passiveacquired passive
Acquired by administration of protective antibodies; Acquired by administration of protective antibodies; for example, the transfer of preformed antibodies, for example, the transfer of preformed antibodies, gamma globulin for hepatitis, temporary gamma globulin for hepatitis, temporary
Classification of natural immunityClassification of natural immunity
Anti-infectious Anti-infectious Anti-bacterialAnti-bacterial
Anti-viralAnti-viral
Anti-toxic Anti-toxic
Anti-fungal Anti-fungal
Anti-protozoa Anti-protozoa
Noninfectious Noninfectious Auto-immune Auto-immune
Associated with Associated with transplantation transplantation
Anti-tumoral Anti-tumoral
ReproductiveReproductive
Fundamental features of specific Fundamental features of specific immune response immune response
The response involves two sets of lymphocytes acting The response involves two sets of lymphocytes acting together with the phagocytic cells.together with the phagocytic cells.
The response is highly specificThe response is highly specific ( (a response made to one a response made to one disease generally confers immunity only to that disease and not to disease generally confers immunity only to that disease and not to
others).others). The response has memory so that once the host has The response has memory so that once the host has responded to a foreign invader, a second response to responded to a foreign invader, a second response to the same foreign invader is more rapid and greatly the same foreign invader is more rapid and greatly enhanced.enhanced.
The response is capable of discriminating between host The response is capable of discriminating between host and foreign substances.and foreign substances.
Functions of immune systemFunctions of immune system
searching
recognition
destruction
of foreign, nonself substances
Human major histocompatibility Human major histocompatibility complex (MHC)complex (MHC)
Characteristic of MHC antigensCharacteristic of MHC antigens MHCMHC – – MMajor ajor HHistocompatibility istocompatibility CComplexomplex HLAHLA – – HHuman uman LLeukocyte eukocyte AAntigen ntigen This receptor complex plays a vital role in recognition of self by the This receptor complex plays a vital role in recognition of self by the
immune system and in rejection of foreign tissue. immune system and in rejection of foreign tissue.
MHC IMHC I antigen presents on the surface of every nucleus- antigen presents on the surface of every nucleus-contained cell and is marker of self. MHC I regulates contained cell and is marker of self. MHC I regulates acceptance or rejection of tissue grafts.acceptance or rejection of tissue grafts.MHC IIMHC II antigens located primarily on macrophages and antigens located primarily on macrophages and B cells and regulate immune response. It functions in B cells and regulate immune response. It functions in cooperative immune responses to antigens mounted by cooperative immune responses to antigens mounted by these cells and T-cells. these cells and T-cells. MHC IIIMHC III genes code for certain secreted complement genes code for certain secreted complement components such as C2 and C4.components such as C2 and C4.
Antigens (Ag) Antigens (Ag)
The word The word antigenantigen is a combination of the is a combination of the words words antiantibody and body and gengenerator.erator.
AntigensAntigens are substances that are are substances that are genetically foreign and can trigger the genetically foreign and can trigger the development of specific immune reactions development of specific immune reactions after penetration in organismafter penetration in organism
Major properties of antigensMajor properties of antigens
ForeignnessForeignness (meaning that it is not a normal (meaning that it is not a normal constituent of the body)constituent of the body)
ImmunogenicityImmunogenicity ( (antigenicity) (ability to stimulate antigenicity) (ability to stimulate antibody formationantibody formation))SpecificitySpecificity
Chemical categories of antigensChemical categories of antigens
Chemicals Chemicals Object Object
Proteins and Proteins and polypeptides polypeptides
Enzymes, albumin, antibodies, hormones, Enzymes, albumin, antibodies, hormones, exotoxinsexotoxins
Lipoproteins Lipoproteins Cell membraneCell membrane
Glycoproteins Glycoproteins Viral envelope Viral envelope
Nucleoproteins Nucleoproteins (DNA complexed to proteins, but not pure (DNA complexed to proteins, but not pure DNADNA
Polysaccharides Polysaccharides Bacterial capsuleBacterial capsule
Lipopoly-Lipopoly-saccharides saccharides
Cell wall of gram-negative bacteria Cell wall of gram-negative bacteria
Antigenic determinant (epitop)Antigenic determinant (epitop)
Antigen
Epitops
Antigens determinants of virus Antigens determinants of virus
(a) Microbes such as viruses present various sites that serve as separate antigenic determinants.
(b) Inset indicates that each determinant (1, 2, 3, 4) will stimulate a different lymphocyte and antibody response.
Antigen structure of bacteriaAntigen structure of bacteria
О-antigen
(cell wall)
К-antigen
(microcapsule)
Н-antigen
(flagella)
Haptens Haptens Hapten is a small foreign molecules that consist only of a determinant group and are too small by themselves to elicit an immune response
Hapten has foreignness and specificity but has not immunogenicity
When hapten combine with larger molecule-carrier such protein it can become antigenic