IMMUNE SYSTEMIMMUNE SYSTEM

Chapter 21Chapter 21

COMPONENTSCOMPONENTS

INNATE IMMUNITYINNATE IMMUNITY

Innate DefensesInnate Defenses

Surface BarriersSurface Barriers– SkinSkin– Mucous membranesMucous membranes

Innate DefensesInnate Defenses

Chemical BarriersChemical Barriers– MucusMucus– LysozymesLysozymes

SalivaSaliva Lacrimal fluidLacrimal fluid

– High acidityHigh acidity Gastric juicesGastric juices UrineUrine Vaginal secretionsVaginal secretions

– SebumSebum

Innate DefensesInnate Defenses Cellular Cellular

DefensesDefenses– Phagocytic cellsPhagocytic cells

Macrophages or Macrophages or MonocytesMonocytes

– Free (alveolar)Free (alveolar)– Fixed (Kupffer)Fixed (Kupffer)

NeutrophilsNeutrophils Dendritic cellsDendritic cells

Phagocytic Phagocytic MobilizationMobilization

Alarm callAlarm call VasodilationVasodilation Increased Increased

permeability permeability LeukocytosisLeukocytosis MarginationMargination DiapedesisDiapedesis ChemotaxisChemotaxis

Phagocytic MechanismPhagocytic Mechanism

AdherenceAdherence IngestionIngestion

– PhagosomePhagosome DigestionDigestion

– LysosomeLysosome– PhagolysosomePhagolysosome

ResolutionResolution

Innate DefensesInnate Defenses

Cellular DefensesCellular Defenses– PhagocytesPhagocytes– Inflammatory CellsInflammatory Cells

Mast CellsMast Cells BasophilsBasophils Eosinophils?Eosinophils?

– Natural Killer CellsNatural Killer Cells

Chemical DefensesChemical Defenses

Inflammatory ResponseInflammatory Response

Anti-microbial AgentsAnti-microbial Agents

InterferonsInterferons

Anti-microbial AgentsAnti-microbial Agents

InterferonsInterferons

ComplementComplement

PyrogensPyrogens

ADAPTIVE IMMUNITYADAPTIVE IMMUNITY

Adaptive ImmunityAdaptive Immunity

SpecificSpecific

SystemicSystemic

MemoryMemory

Adaptive DefensesAdaptive Defenses

Antigens = “self” versus “non-self”Antigens = “self” versus “non-self” Major Histocompatibility Complex (MHC)Major Histocompatibility Complex (MHC)

– MHC IMHC I– MHC IIMHC II

Adaptive DefensesAdaptive Defenses

Adaptive DefensesAdaptive Defenses

Antibody-Mediated Antibody-Mediated ImmunityImmunity

Also known as “humoral immunity”Also known as “humoral immunity”

Involves B lymphocytesInvolves B lymphocytes

DIRECTLY recognizes antigenDIRECTLY recognizes antigen

B lymphocytes undergo clonal B lymphocytes undergo clonal expansionexpansion

Clonal Expansion of B Clonal Expansion of B CellsCells

Primary and Secondary Primary and Secondary Humoral ResponsesHumoral Responses

Antibody StructureAntibody Structure

Antibody TypesAntibody Types

Antibody TypesAntibody Types

Antibody FunctionAntibody Function

Active and PassiveActive and PassiveHumoral ImmunityHumoral Immunity

Cell-Mediated Cell-Mediated ImmunityImmunity

Involves T lymphocytesInvolves T lymphocytes Cannot recognize antigen directlyCannot recognize antigen directly Antigen must be presented by Antigen must be presented by

APCAPC T lymphocytes are more diverse:T lymphocytes are more diverse:

Helper T cellsHelper T cells Cytotoxic T cellsCytotoxic T cells Suppressor T cellsSuppressor T cells Memory T cellsMemory T cells

T-Cell EducationT-Cell Education

Cell-Mediated Cell-Mediated ImmunityImmunity

Stimulation of TStimulation of TCC cells cells

Cell-Mediated Cell-Mediated ImmunityImmunity

Stimulation of TStimulation of THH cells cells

Co-StimulationCo-Stimulation

Function of TFunction of TCC cells cells

Function of TFunction of TCC cells cells

Clonal Expansion ofClonal Expansion ofT CellsT Cells

Summary of Components Summary of Components of Adaptive Immunityof Adaptive Immunity

Summary of Components Summary of Components of Adaptive Immunityof Adaptive Immunity

Homeostatic Homeostatic ImbalancesImbalances

Organ transplant and tissue rejectionOrgan transplant and tissue rejection– AutograftAutograft– IsograftIsograft– AllograftAllograft– XenograftXenograft

ImmunodeficiencyImmunodeficiency– Severe combined immunodeficiency Severe combined immunodeficiency

syndrome (SCID)syndrome (SCID)– Acquired immune deficiency syndrome Acquired immune deficiency syndrome

(AIDS)(AIDS)– Human immunodeficiency virus (HIV)Human immunodeficiency virus (HIV)

Homeostatic Homeostatic ImbalancesImbalances

Autoimmune diseasesAutoimmune diseases– Multiple sclerosisMultiple sclerosis– Grave’s diseaseGrave’s disease– Type I diabetesType I diabetes– Systemic lupusSystemic lupus– Myasthenia gravisMyasthenia gravis– GlomerulonephritisGlomerulonephritis– Rheumatoid arthritisRheumatoid arthritis

Homeostatic Homeostatic ImbalancesImbalances

HypersensitivitiesHypersensitivities– Immediate (Type Immediate (Type

I)I)

– Subacute Subacute Cytotoxic (Types Cytotoxic (Types

II)II) Immune-complex Immune-complex

(Type III)(Type III)

– Delayed (Type IV)Delayed (Type IV)

END CHAPTER 21END CHAPTER 21