Immunology Physio Flashcards
Describe the 2 intrinsic immune systems
- innate (nonspecific - born with it)
- adaptive (specific - after exposure)
What are the two lines of defense of the innate immune system
- 1st: external membranes (contain: keratin, enzymes, toxins, acidity, lipids, lysozyme, mucus)
- 2nd: antimicrobial proteins, phagocytes, etc. that inhibit spread and drive inflammation
Describe the line of defense of the adaptive immune system
- takes longer than innate
- attacks particular foreign substances
- Humoral immunity: B cells
- Cellular immunity: T cells
Describe macrophages in the immune system
- chief phagocytic cells
- free macrophages wander through tissues
- fixed macrophages in some organs (Langerhan’s of skin, Kuppfer of liver, Microglia of brain)
When do neutrophils become phagocytic
When meeting infectious material in tissues
What are lysosomes responsible for in phagocytosis
enzymes that digest particles engulfed in a phagocyte
Describe natural killer cells
- large granular lymphocytes
- in spleen, LNs, bone marrow, blood
- lyse virus infected cells & Ab coated cells
- enhance inflammatory response
List the 5 cardinal signs of acute inflammation
- redness (rubor)
- heat (calor)
- swelling (tumor)
- pain (dolor)
- impaired function (functio laesa)
List some inflammatory mediators/cytokines
- histamine from mast cells
- blood proteins
- kinins, prostaglandins, leukotrienes, complements
Describe interferons
complement proteins
- secreted by virus infected cells which enter neighboring cells and produce antiviral proteins to block reproduction
- produced in lymphocytes, WBCs, fibroblasts
- reduce inflammation, activate macrophages & NK cells
Describe complement proteins
- cascade of 20+ serum proteins/glycoproteins that circulate in inactive forms
- destroy foreign substances & amplify inflammation
- cell lysis (opsonization)
What are the two complement activation pathways
- classical: activated by Ag-Ab complexes
- alternative: activated by components of pathogen surfaces
What is the cellular mechanism of fever
leukocytes & macrophages exposed to foreign substances secrete pyrogens which increase body’s temp
What are the benefits of moderate fever
- causes liver & spleen to sequester iron & zinc
- increases metabolic rate & repair rate
(high fevers can denature important enzymes)
What are the functions of the adaptive/acquired immune system
- protect against infectious agents/abnormal cells
- amplifies inflammatory response
- activates complement systems
Define antigens
substances that mobilize the adaptive defenses and provoke an immune response
Define immunogens
substance that always gives an immune response (foreign protein, polysacc., lipids, nucleic acids)
Define haptens
incomplete/baby antigens that are only immunogenic when attached to body proteins (poison ivy, animal dander, detergents, cosmetics, drugs)
Define Epitope/Antigenic determinants
certain parts of an entire antigen that are immunogenic
- Abs & lymphocyte receptors bind to them
What are MHC proteins (major histocompatibility complex)
- self antigen
- Class I: found in all body cells (nucleated cells & platelets)
- Class II: found on certain immune cells (dendritic cells, macrophages)
Where are B cells and T cells matured
B: red bone marrow
T: thymus
(Naive/Unexposed B & T cells exported to LNs, spleen, lymphoid organs)
Describe the 2 cells that T cells differentiate into
- CD4: helper T, aid in humoral & cell-mediated immunity
- CD8: cytotoxic T, cell mediated response against viral/tumor cells
Describe Ag Presenting cells (APCs)
Engulf Ags & present fragments to be recognized by T cells
- dendritic cells in connective tissue & epidermis
- macrophages in connective tissue & lymphoid organs
- B cells
Define antigen challenge
first encounter between an antigen and a naive immunocompetent lymphocyte (usually in spleen or LN)
(If B cell, will trigger Abs & immune response)
Define clonal selection
Stimulated B cell grows to form a clone of identical cells bearing the same Ag specific receptors (usually requires T cell help)
Define naturally acquired active humoral immunity
infection or contact with a pathogen
Define artificially acquired active humoral immunity
vaccination or dead/attenuated pathogens
Define naturally acquired passive humoral immunity
Abs passed from mom to fetus via placenta or breast milk
Define artificially acquired passive humoral immunity
injection of immune serum (gamma globulin/antibodies)
Describe IgM
IgM: pentamer, first Ab released, acute
Describe IgA
IgA: monomer/dimer in mucus/secretions
Describe IgD
IgD: monomer attached to B cell surfaces
Describe IgG
IgG: monomer, 80% of Abs in plasma, from chronic/late infection, can cross placenta
Describe IgE
IgE: monomer, allergies & parasitic infections
CD4 cells become ____ when activated and CD8 cells become _____ when activated
CD4 = helper T
CD8 = cytotoxic
Describe severe combined immunodeficiency syndrome (SCID)
- genetic defect with deficiency of B and T cells
- abnormalities in interleukin receptors
- fatal, treat with bone marrow transplant
Describe Hodgekin’s disease
- acquired immunodeficiency from cancer of B cells
- depresses lymph node cells & immunity
Describe AIDS
- crippling of immune system by interfering with helper T activity (CD4)
- susceptible to opportunistic infection
Describe autoimmune diseases
- immune system loses ability to distinguish self from foreign
- autoantibodies & cytotoxic T cells attack body tissue
Describe Type 1/Acute hypersensitivity (allergy)
- immediate immune response after contact with allergen
- asymptomatic initially but becomes sensitized (local or systemic)
- involves IL-4 secreted by T cells which stimulates B cells to secrete IgE
Describe anaphylactic shock (Type 1 hypersensitivity)
systemic response to allergen directly entering blood
- systemic histamine release causing: constriction of bronchioles, sudden vasodilation, HoTN
- treat with epi
Describe Type 2/cytotoxic hypersensitivity
- subacute
- **Ab mediated hypersensitivity against our own cells/receptors/membranes
- mediated by IgG or IgM
- slow onset with long duration
(ex. transfusion reaction, autoimmune hemolytic anemia (Graves, MG, Goodpasture))
Describe Type 3 hypersensitivity
- subacute
- complexes deposted in various tissues
- high levels of circulating IgG or IgM
- intense inflammation, local cell lysis
(SLE, RA, PSGN)
Describe Type 4 delayed hypersensitivity
- onset extremely slow (days)
- involves helper T cells, activated macrophages, cytotoxic T cells
(allergic contact dermatitis, poison ivy, Mantoux test)
