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Immunochemistry (1) Kordofan

Immunochemistry (1) Atif Hassan Khirelsied B.Sc. M.Sc. Ph D Biochemistry B S M S Ph.D. Bi h i Faculty of Medicine International University of Africa LEARNING OBJECTIVES: 1. To recognize the significance of the immune system in combating infection and disease. 2. To distinguish between the innate ( g (non-specific) and p ) adaptive (specific) immune systems. 3. 3 To understand the mechanisms of combating infection/disease (killing pathogens). 4. To identify the humoral and cellular components

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Dr. Atif Hassan Khirelsied
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137 views34 pages

Immunochemistry (1) Kordofan

Immunochemistry (1) Atif Hassan Khirelsied B.Sc. M.Sc. Ph D Biochemistry B S M S Ph.D. Bi h i Faculty of Medicine International University of Africa LEARNING OBJECTIVES: 1. To recognize the significance of the immune system in combating infection and disease. 2. To distinguish between the innate ( g (non-specific) and p ) adaptive (specific) immune systems. 3. 3 To understand the mechanisms of combating infection/disease (killing pathogens). 4. To identify the humoral and cellular components

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Dr. Atif Hassan Khirelsied
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Immunochemistry (1)

Atif Hassan Khirelsied


B.Sc. M.Sc. Ph D Biochemistry B S M S Ph.D. Bi h i

Faculty of Medicine International University of Africa

LEARNING OBJECTIVES:
1. To recognize the significance of the immune system in combating infection and disease. 2. To distinguish between the innate ( g (non-specific) and p ) adaptive (specific) immune systems. 3. 3 To understand the mechanisms of combating infection/disease (killing pathogens). 4. To identify the humoral and cellular components of innate immunity. y 5. To describe general characteristics of the specific immune response .

LEARNING OBJECTIVES:
6. To compare and contrast primary and secondary antibody responses. 7. 8. 8 9. To discuss the general properties of all immunoglobulins. To describe the basic structure of immunoglobulins . To relate immunoglobulin structure with function.

10. To d fi i 10 T define immunoglobulin h l b li hypervariable and f i bl d framework k regions. 11. To define immunoglobulin classes and subclasses, types yp and subtypes . 12. To describe the structures and properties of immunoglobulin classes. classes

The immune system y


Weareconstantlyexposedtoinfectiousagents. Theimmunesystemenablesustoresistinfections andmaintainhomeostasis. and maintain homeostasis. It detects pathogens and disting ishes them from Itdetectspathogensanddistinguishesthemfrom ourownnormalcellsandtissues.

The immune system


Isacomplexnetworkof l k f organs,tissues,cellsand moleculeswhichprotect l l h h bodiesagainstinvading microorganismsand i i d theirtoxins

The functions of the immune system


1. Defenseagainstinvadingpathogens(virusesandbacteria) 2. Removalof'wornout'cells(e.g.,oldRBCs)andtissue debris(e.g.,frominjuryordisease) ( g, j y ) 3. Identificationanddestructionofabnormalormutantcells (primarydefenseagainstcancer) 4. Rejectionof'foreign'cells(e.g.,organtransplant)

The immune system y


Theimmunesystemiscomposedoftwomajor subdivisions: bdi i i 1. Innate ornonspecificimmunesystem p y 2. Adaptiveorspecificimmunesystem

The disorders of the immune system y


1. Inappropriateresponses:
Allergies responsetonormallyharmlesssubstances Autoimmunediseases(rheumatoidarthritis,type1 A t i di (h t id th iti t 1 diabetesmellitusandlupuserythematous).

2. Immunodeficiencydiseases:
Heriditary (severe combined immunodeficiency) (severecombinedimmunodeficiency) Acquiredduetoinfection(HIV).

The components of the immune system p y

1. Innate,natural;bodymakeup,phagocytic cells , ; y p, p g y 2. Adaptive,acquired;itisthefunctionof 2 Adaptive acquired; it is the function of lymphocytes,TandBcells(onlyinvertebrates)

The innate immune response p

Innateimmunityconsistsofsystemsthatareready forimmediateactivationpriortoattackbya pathogen. It is rapid initiating within minutes of pathogen Itisrapid,initiatingwithinminutesofpathogen invasion.

The innate immune response p

Theinnatesystemincludes:
Physicalbarriers Chemical barriers Chemicalbarriers Andcellularbarriers.

The innate immune response p


Thephysicalbarriers
Skin. Mucosalmembranes.

Thechemicalbarriers
LowpH p Specializedsolublemolecules

Thebiologicalbarriers
Commensal flora

The physical barriers p y


Ski Skin,mechanicalbarrier,1st li h i lb i 1 t lineofdefense. fd f Coughingandsneezingmechanicallyeject pathogens. Flushingactionoftearsandurinealsoexpels pathogens. Mucusservestotrapandexpelmicroorganisms

The chemical barriers


Th ki Theskinandrespiratorytractsecreteantimicrobial d i i i bi l peptides suchasthedefensins Enzymessuchaslysozyme andphospholipase A in saliva,tears,andbreastmilkarealsoantibacterial. li t db t ilk l ti b t i l In the stomach Hcl and proteases ser e as defenses Inthestomach,Hcl andproteases serveasdefenses againstpathogens.

The biological barriers g


IntheUGTand GITtracts,commensal floraserveas biologicalbarriersbycompetingwithpathogenic bi l i l b i b ti ith th i bacteriafornutrientsandbychangingthepH. y g g p

Organ or tissue Skin Mouth and upper alimentary canal Stomach Small intestine Large intestine Airways and lungs

Innate mechanism protecting skin/epithelium Antimicrobial peptides, fatty acids in sebum Enzymes, anti-micorbial peptides, and sweeping of surface by directional flow of fluids towards stomach Low pH, digestive enzymes, anti-micorbial peptides, and flow towards intestine. Digestive enzymes, anti-micorbial peptides, and flow towards large intestine Normal intestinal flora compete with invading microbes, fluid/feces expelled from rectum. Cilia sweeps mucus outward, coughing, sneezing expel mucus, macrophages in alveoli of lungs

The cellular components of the innate immune system


1. Phagocytes(monocytes,macrophages, neutrophils). neutrophils) 2. Naturalkiller(NK)cells. 3. Dendritic cells.

Phagocytosis

Phagocytosis

The major function of the innate immune system


1. Recruitmentofimmunecellstositesofinfection 1 R it t fi ll t it f i f ti andinflammation. 2. Complementcascadeactivation. 3. Identificationandremovalofforeignsubstances. 4. Antigenpresentation(activationoftheadaptive g p ( p immunesystem).

The characteristics of the innate immune system


1. Nonspecific. 2. Rapid 3. Hasnomemory. 3 Has no memory 4. Differentiationbetweenselfandnonself.

The adaptive immune response

Consistsofhighlyspecialized,systemiccellsand processesthateliminatepathogensandtoxins processes that eliminate pathogens and to ins

Triggeredwhenapathogenevadestheinnate immunesystemandgeneratesathresholdlevelof antigen.

The characteristics of the adaptive immune response


Acquired immunity. d Specific (tailormade)immunity. Relativelyslow. Hashugediversity( Has huge diversity (versatility) ). Hasmemory(quickerandmoreefficientinthe2nd response)(vaccines). response) (vaccines)

The major function of the adaptive immune response


The recognition of specific non selfantigensinthe Therecognition ofspecific nonself antigens in the presenceofself,duringtheprocessofantigen presentation. presentation. The generation of responses that are tailored to Thegenerationofresponses thataretailoredto maximallyeliminatespecificpathogensorpathogen infectedcells. infected cells. The development of immunological memory to quickly Thedevelopmentofimmunologicalmemory toquickly eliminateapathogeninsubsequentinfections.

The memory of the adaptive immune response


The 1st e pos re to anti en enerates primar imm ne The1 exposuretoantigengeneratesprimaryimmune response afteralatentperiodofabout1week. p p

Thesubsequentexposurestothesameantigen generatesecondaryimmuneresponseswhich immediateandbrisk. immediate and brisk

The memory of the adaptive immune response y p p

IgG is the major antibody in the secondary immune response p

Comparisonoftheimmuneresponses p p Innate
Nonspecific Immediateresponse Cellularandhumoral Cellular and humoral Hasnomemory y Foundinallformsoflife

Adaptive
Antigenspecific Laggingresponse Cellularandhumoral Cellular and humoral Hasmemory y Foundonlyinvertebrates

Comparison of the innate and adaptive immunity. Attribute


Response time Specificity

Innate Immunity
Minutes/hours Specific for molecules and molecular patterns A limited number of germline encoded receptors None Perfect, no microbe specific patterns in host Many antimicrobial peptides M ti i bi l tid and proteins Phagocytes (monocytes, macrophages, neutrophils) NK cells, dendritic cells

Adaptive Immunity
Days Highly specific, discriminate minor differences in molecular structures t t Highly diverse, very large number of receptors arising by genetic recombination ti bi ti Persistent memory Very good, occasional failure of discrimination Antibodies A tib di

Diversity

Memory responses Self/nonself discrimination Soluble S l bl components t

Major cell types

T cells, B cells, antigen presenting cells

Immunological definitions and terminology


Antigen ( (immunogen) ) Short for antibody generators Shortforantibodygenerators Definedasforeignsubstancesthatbindtospecific g p immunereceptorsandelicitanimmuneresponse.

Immunological definitions and terminology


Haptens Smallmoleculeswhichfailtoprovideepitopes for BorTcellbythemselves(theyneedacarrier knownasadjuvant).

An antigen provides multiple epitopes (antigenic determinants)

Copyright 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Dinitrophenyl

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