Flashcards in Innate and Adaptive Immunity Deck (103)
What are the steps for phagocyte mobilization?
1. Leukocytosis ( release of neutrophils from bone marrow in response to leukocytosis-inducing factors from injured cells)
2. Margination (neutrophils cling to the walls of capillaries in the inflamed area)
3. Diapedesis of neutrophils
4. Chemotaxis (inflammatory chemicals, chemotactic agent, promote postive chemotaxis of neutrophils)
What are the mechanisms buy which phagocytosis works to destroy pathogens? 3 ways
1. Destruction of pathogens (acidification and digestion by lysosomal enzymes)
2. Respiratory burst
3. 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.
3. Inflammatory response (macrophages, mast cells, WBC, inflammatory chemicals)
4. Antimicrobial proteins (complement proteins and interferons)
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?
What FIRST needs to happen to start the process of inflammation? (what promotes it, and what causes the that promotion to occur?)
1. macrophages and epithelial cells of boundary tissues bear TLRs
2. TLRs actviated trigger the release of cytokines
3. 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.
1. virus enters cell
2. interferon gene inside cell turns on
3. cell produces interferon molecules
4. interferon is then secreted from that cell
5. interferon enters neighboring cells--or binds to cell
6. interferon stimulates cell to turn on genes for antiviral proteins
7. 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?
What IFN do fibroblasts secrete?
What cells do IFNs activate?
macrophages and mobilize NK cells
What is the function of interferons?
-activate macrophages and mobilize NK cells
What do genetically engineered INFs do?
-antiviral agent against hepatitis, genital warts
What are the three phases of complement?
1. Initiation or activation
2. amplification of inflammation
3. 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?
What does MAC do?
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
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)