Acquired Immune Responses Hugh B. Fackrell filename : JWR11v7.ppt

Acquired Immunity:Outline Acquired vs Innate immunity Immunogens & Antigens MHC Functions of Acquired immunity Components of Immune Response Humoral Immunity Cell mediated immunity Regulation of immunity

Adaptive vs Innate Immunity

Definitions Immunogen Antigen Any compound that combines with the products of an immune response and triggers the immune response Antigen Any compound that combines with the products of an immune response

Antigen: interaction

Caveat Immunogenicity is not an inherent characteristic of a molecule Immunogen MUST first be recognized as foreign by the body Eg Blood transfusions RBCs are not recognized as immunogenic unless blood typed incorrectly

Major Histocompatability Complex

MHC-1

MHC-1 Function

MHC-2: Structure

MHC-2 Function

Acquired Immunity Definition Characteristics Acquired immunity( AKA adaptive immunity) is an altered reactivity to a specific compound that follows exposure to that compound Characteristics Specificity Memory

Acquired Immunity: definition The altered reactivity will not be to all compounds, just those compounds to which the animal has been exposed The animal has a heightened specific response on second and subsequent exposures because the body remembers previous contacts

Functions of Acquired Immunity Discrimate between self and non self for: Defence destruction of foreign molecules Homeostasis removal of dead or damaged cells Surveillance control of mutant or cancer cells

Components of Immune Response Cells B cells T cells NK cells Macrophages MOLECULES Major Histocompatbility Complex Regulatory Proteins cytokines lymphokines

Two Forms of Acquired Immunity Humoral Immunity lymphocytes react indirectly on non self molecules via antibodies Cell mediated immunity Lymphocytes act directly on the non self molecules

Humoral Immunity

Angels & Devils

Antibody: a Flexible mediator

Immunoglobulin Classes Immunoglobulin A IgA, mA Immunoglobulin D IgD, mD Immunoglobulin E IgE, mE Immunoglobulin G IgG, mG Immunoglobulin M IgM, mM

IgM: Structure

IgM: Functions Antigen receptor for B cell Short term protection binds tightly to antigen (high avidity)

Primary vs Secondary Response

Structure of IgG

IgG: Functions Bind antigen in tissue fluids Promote destruction of antigen activates complement Promote phagocytosis binds to Fc receptors on macrophages Passive protection of fetus binds to receptors on placenta transferred to fetal circulation

Structure of IgA

Secretion of IgA

IgA; Functions Protects body surfaces against invading microbes Secretory IgA - transported to epithelium secreted in mucus, milk & tears Blood IgA - transported to liver binds to hepatocytes secreted into bile

Structure of IgE

IgE: Functions Mediates inflammatory response Immunity to parasitic worms Mediates many allergies (type I)

Antibody Specificity Antibodies distinguish between: Diseases measles & mumps Macromolecules proteins, complex carbohydrates Molecules amino acids, sugars Submolecular D& L isomers ortho, meta, para positions

Clonal Selection: B cells

Cell mediated Immunity

T cells

Cell mediated clonal selection

Role of Macrophages

Monocyte

Macrophage Activation products

Macrophages & T cells

T cells interacting with Macrophage

Regulation of Immunity

Range of immune responses

Antigen Processing

Cellular interactions during the humoral response

Requirements for a complete immune response Lymphocytes B cells Tcells Macrophages critical accessory cells Complement combines with antibody to enhance destruction

Adverse effects of Immunity