Immune SystemImmune System

Chapter 43Chapter 43

Introduction to the Immune Introduction to the Immune SystemSystem

An animal must defend itself against An animal must defend itself against unwelcome intruders.unwelcome intruders.

It must also deal with abnormal body It must also deal with abnormal body cells, which, in some cases, may develop cells, which, in some cases, may develop into cancer.into cancer.

Two major kinds of defense have evolved Two major kinds of defense have evolved to counter such threats.to counter such threats.

Innate DefensesInnate Defenses Acquired DefensesAcquired Defenses

Overview of the Immune Overview of the Immune SystemSystem

External Barriers:External Barriers:

SkinSkin Mucous Mucous

membranesmembranes SecretionsSecretions

Internal Cellular Defenses:Internal Cellular Defenses:

Phagocytic cellsPhagocytic cells

NeutrophilsNeutrophils MonocytesMonocytes EosinophilsEosinophils Dendritic cellsDendritic cells

Internal Cellular DefensesInternal Cellular Defenses

Phagocytic ResponsesPhagocytic Responses

PseudopodiaPseudopodia IngestionIngestion VacuoleVacuole Fuse with lysosomeFuse with lysosome DigestionDigestion ExocytosisExocytosis

Internal Cellular Defenses:Internal Cellular Defenses:

Natural Killer CellsNatural Killer Cells

Non-specificNon-specific PerforinsPerforins ApoptosisApoptosis

Internal Chemical Defenses:Internal Chemical Defenses:

InterferonsInterferons

Complement proteinsComplement proteins

Inflammatory ResponseInflammatory Response

Inflammatory ResponseInflammatory Response

Cardinal signs of Cardinal signs of inflammationinflammation

Local versus Local versus systemic systemic inflammationinflammation

Septic shockSeptic shock

ACQUIRED IMMUNITYACQUIRED IMMUNITY

All cells have cell All cells have cell surface surface macromolecules macromolecules

Adaptive immunity Adaptive immunity is sensitive to is sensitive to specific infections specific infections

Antigens Antigens distinguish self distinguish self versus non-selfversus non-self

ACQUIRED IMMUNITYACQUIRED IMMUNITY

ACQUIRED IMMUNITYACQUIRED IMMUNITY

Humoral ImmunityHumoral Immunity

Also known as Also known as antibody-mediated antibody-mediated immunityimmunity

Utilizes B-Utilizes B-lymphocyteslymphocytes

Recognizes antigen Recognizes antigen directlydirectly

Made in the bone Made in the bone marrowmarrow

Clonal Selection and Clonal Selection and ProliferationProliferation

Humoral ImmunityHumoral Immunity

Antibody StructureAntibody Structure

Antibody ClassesAntibody Classes

Antibody ClassesAntibody Classes

Antibody FunctionsAntibody Functions

Cell-Mediated ImmunityCell-Mediated Immunity

Utilizes T-Utilizes T-lymphocyteslymphocytes

T-cells are made in T-cells are made in the bone marrow the bone marrow but mature in the but mature in the thymus gland.thymus gland.

Cannot recognize Cannot recognize antigens directlyantigens directly

Cell-Mediated ImmunityCell-Mediated Immunity

CLASS I MHC PROTEIN

CLASS II MHC PROTEIN

Helper T-Lymphocyte Helper T-Lymphocyte StimulationStimulation

Helper T-cells stimulate B-Helper T-cells stimulate B-cellscells

Cytotoxic T-Lymphocyte Cytotoxic T-Lymphocyte StimulationStimulation

Overview of Adaptive Overview of Adaptive ImmunityImmunity

Adaptive ImmunityAdaptive Immunity

Problems with the Immune Problems with the Immune SystemSystem

Blood Transfusion ReactionBlood Transfusion Reaction Tissue RejectionTissue Rejection AllergiesAllergies Autoimmune diseaseAutoimmune disease ImmunodeficienciesImmunodeficiencies

Blood Transfusion ReactionsBlood Transfusion Reactions

Blood Transfusion ReactionsBlood Transfusion Reactions

Rhesus FactorRhesus Factor

Blood Blood TypeType

Presence Presence of D of D Antigen?Antigen?

Type of Type of AntibodyAntibody??

ReceiveReceive??

Rh PositiveRh Positive

YesYes NoneNone + and -+ and -

Rh Rh NegativeNegative NoNo Anti-DAnti-D - only- only

Tissue Transplant and Tissue Transplant and RejectionRejection

AutograftAutograft IsograftIsograft AllograftAllograft XenograftXenograft

Allergies or Allergies or HypersensitivitiesHypersensitivities

Type IType I

Type IIType II

Type IIIType III

Type IVType IV

Autoimmune DiseasesAutoimmune Diseases

Multiple sclerosisMultiple sclerosis

Rheumatoid Rheumatoid arthritisarthritis

Systemic lupusSystemic lupus

Grave's diseaseGrave's disease

Type I diabetes Type I diabetes mellitusmellitus

Immunodeficiency DiseasesImmunodeficiency Diseases

Primary Primary ImmunodeficiencyImmunodeficiency

a.k.a. “inborn”a.k.a. “inborn” SCIDSCID

Secondary Secondary ImmunodeficiencyImmunodeficiency

a.k.a. “acquired”a.k.a. “acquired” DrugsDrugs Stress and Hodgkin’sStress and Hodgkin’s AIDSAIDS