Innate and Adaptive Immunity Flashcards
What are the steps for phagocyte mobilization?
- Leukocytosis ( release of neutrophils from bone marrow in response to leukocytosis-inducing factors from injured cells)
- Margination (neutrophils cling to the walls of capillaries in the inflamed area)
- Diapedesis of neutrophils
- Chemotaxis (inflammatory chemicals, chemotactic agent, promote postive chemotaxis of neutrophils)
What are the mechanisms buy which phagocytosis works to destroy pathogens? 3 ways
- Destruction of pathogens (acidification and digestion by lysosomal enzymes)
- Respiratory burst
- Oxidizing chemicals
What are the innate external defenses?
skin, mucous membranes and secretions, skin acidity, lipids in sebum, dermcidin in sweat, HCL in stomach, lysozyme in saliva, mucus, haris, cilia
What are the general innate internal defenses (cells and chemicals)? Meaning, what does the innate immune response do, what is it responsible for? As well as cells, and proteins.
- phagocytes
- NK
- Inflammatory response (macrophages, mast cells, WBC, inflammatory chemicals)
- Antimicrobial proteins (complement proteins and interferons)
- Fever
What are the functions and characteristics of NK cells?
- large granular lymphocytes
- target cells that lack “self” cell-surface receptors WITHOUT previous exposure to surface antigens
- induce apoptosis in cancer cells and virus infected cells
- secrete potent chemicals that enhance the inflammatory response
When is inflammation triggered? How does it help in the immune response?
- triggered whenever body tissues are injured or infected
- prevents the spread of damaging agents
- disposes of cell debris and pathogens
- sets stage for repair
cardinal signs of inflammation are?
redness swelling heat pain immobility (sometimes)
What FIRST needs to happen to start the process of inflammation? (what promotes it, and what causes the that promotion to occur?)
- macrophages and epithelial cells of boundary tissues bear TLRs
- TLRs actviated trigger the release of cytokines
- Cytokines promote inflammation
What are the inflammatory mediators?
What are they released by?
- –histamine (from mast cells), blood proteins, kinins, prostaglandins, leukotrienes and complement
- –released by injured tissues, phagocytes, lymphocytes, basophils and mast cells
What do inflammatory chemicals cause?
- dilation of arterioles, resulting in hyperemia
- increased permeability of local capillaries and edema =(leakage of exudate)
what is exudate? What does it contain?
- -exudate is a mass of cells and fluid that has seeped out of blood vessels or an organ, especially in inflammation
- -contains proteins, clotting factors and antibodies
What is the function of exudate?
- -moves foreign material into lymphatic vessels
- -delivers clotting proteins to form a scaffold for repair and to isolate the area (collagen and fibrin)
What are the steps of IFN production? Starting with virus entering cell.
- virus enters cell
- interferon gene inside cell turns on
- cell produces interferon molecules
- interferon is then secreted from that cell
- interferon enters neighboring cells–or binds to cell
- interferon stimulates cell to turn on genes for antiviral proteins
- antiviral proteins block viral reproduction in cell
What interferon do lymphocytes secrete?
gamma = immune interferon
p. 287 (also NK and macrophages)
What IFN do most WBCs secrete?
alpha
What IFN do fibroblasts secrete?
beta
What cells do IFNs activate?
macrophages and mobilize NK cells
What is the function of interferons?
- antiviral
- reduce inflammation
- activate macrophages and mobilize NK cells
What do genetically engineered INFs do?
- antiviral agent against hepatitis, genital warts
- MS treatment
What are the three phases of complement?
- Initiation or activation
- amplification of inflammation
- Membrane attack response (promotes phagocytosis and causes cell lysis)
What does C3a do?
triggers migration of neutrophils in the the tissues to enhance the inflammatory response
What does C3b do?
INITIATES the formation of a MAC and also opsinization
What does C5a do?
inflammation
What does MAC do?
cell lysis
What complement proteins are the mac made of?
C3b starts it, then C5b, C6, C7, C8, C9
What are the benefits of a moderate fever?
- -causes liver and spleen to sequester iron and zinc
- -increases metabolic rate which speeds up healing
What happens to self reactive B cells?
they undergo clonal deletion
or
they undergo receptor editing (rearrangement of their receptors)
What is positive and negative selection in T cells?
First step= positive selection
T cells must recognize self MHC proteins or they will die
Called MHC restriction (survivors are restricted to recognizing antigen on self-MHC)
second step = negative selection
T cells MUST NOT recognize self-antigen or will die = autoimmune diseases!
failure to recongize (bind tightly to) self antigen results in SURVIVAL and continued maturation
What is an antigen?
- substance that can mobilize the ADAPTIVE defense and provoke an immune response
- -most are large, complex molecules not normally found in the body (non self)
What is a complete antigen? What is does it mean that it is immunogenic and reactive? What are some examples?
Immunogenicity = ability to stimulate proliferation of specific lymphocytes and antibodies
Reactivity = ability to react with products of activated lymphocytes and antibodies released
examples: foreign protein, polysaccharides, lipids, nucleic acids (bacteria and viruses)
What is a hapten?
What does the hapten do?
What are some examples?
hapten = small molecules (peptides, nucleotides, hormones)
- -haptens are IMMUNOGENIC when attached to BODY PROTEINS
- cause immune system to mount a HARMFUL attack
ex. poison ivy, animal dander, detergents, cosmetics
What are the adaptive defenses?
- -specific, systemic, has memory!
- protects against infections agents and abnormal body cells
- amplifies inflammatory response
- activates complement
What is the humoral adaptive defense consist of and what is it mediated by and what does it defend against?
B-cells, antibodies, plasma cells
- mediated by B-cell activation and subsequent Ab production
- primary defense against EXTRAcellular microbes and toxins
What is the cell-mediated adaptive defense consist of and what is it mediated by and what does it defend against?
T-cells, Cytotoxic T-cells, Helper T-cells
- -mediated by activation of T-cells
- responsible for the bodies defenses against intracellular mnicrobes such as viruses
What molecule has little or no immunogenicity?
large, chemically simple molecules
plastics, valves, hips
What is an antigenic determinant?
- certain part of antigen that is immunogenic
- Ab and lymphocytes bind to them
- most have numerous antigenic determinants that: 1. mobilize several different lymphocyte pops and 2. form different Ab against it
Finish the sentence. Most naturally occurring antigens have numerous antigenic determinants that:
- mobilize several different lymphocyte populations
2. form different kinds of antibodies against it
What are the the examples of effector and regulatory cells and what do they do?
Regulatory cells = regulatory t, helper t(activate other lymphocytes and phagocytes)
Effector = cytotoxic t, macrophages, other leukocytes
In the adaptive immune response, what destroys antigens and what retain ability to target antigens in future?
effector cells target: cytotoxic t
memory b and memory t helper and t cytotoxic for future
Finish the sentence. Class I and II MHC genes are responsible for encoding HLAs (human leukocyte antigens) which are proteins found on the cell surface that?
Define the patients tissue type!
makes sense for checking these with transplant patients!
What are the APCs that are able to express both classes of MHC molecules?
DCs, monocytes, macrophages, B lymphocytes
** under certain conditions endothelial cells are also able to function as APCs