Chapter 7 Innate Immunity Flashcards
Name the three types of lymphocytes.
- T-cells (thymus cells)
- B-Cells (Bone Marrow derived)
- NK cells (Natural Killer)
Where do T cells mature?
In the Thymus
Where do B cells and NK cells mature?
Bone Marrow
What are the three lines of Defenses in the body?
- First Line-Natural Barriers
- Second Line- Inflammation (innate immunity)
- Adaptive (acquired) Immunity
What are Physical Barriers?
Keeps hazardous materials out of body
Includes hair, epithelium, secretions, skin, linings of the GI, GU, and respiratory tract
What are mechanical barriers?
Act of “mechanical cleansing” of cells due to vomiting, urination, mucous production, sneezing, and coughing.
What are Biochemical Barriers?
Antibacterial peptides in mucous trap organisms
Cathelicidins, defensins, and Collectins (lungs) bind to carbohydrate structures on the surface of a pathogen and recruit other cells and molecules to come destroy.
Microbiomes inhibit colonization: ex. gut and vaginal flora
How do Microbiomes work?
Chemicals (Ammonia, phenols, and indoles) are released to prevent infection.
What is an example of a microbiome in the vagina?
Lactobacillus creates lactic acid and hydrogen peroxide to prevent infection.
What is an example of failed microbiome?
Getting C-diff from extended use antibiotics; Killed the microbiome (flora) in the gut
What is Innate Immunity?
- Process of Inflammation response acts as Second line of body’s defense.
- Takes place same way every time no matter what the stimulus of pathogen is.
- Rapidly initiates
- No memory cells involved. Once the inflammation response is over
What causes activation of the inflammatory response?
infection; mechanical damage; ischemia; nutrient deprivation; temperature extremes; and radiation
What are cardinal signs of the inflammatory process?
Redness, Swelling, heat, inflammation
What are the steps of the inflammatory Response?
- Cellular injury
- Pathogenic invasion
- Mast cells degranulate
- Vascular Response
- Activation of the plasma protien systems (Complement, Clotting, Kinin)
- Release of Cellular Products
How long does an acute inflammatory process take?
8-10 days from onset to healing.
What happens during the vascular response of the inflammatory process?
- Blood vessel dilates (Increases blood flow)
- Vascular permeability increases (lets macrophages in)
- WBC adhere to vessel walls
- WBC migrate thru the vessels (Diapedesis)
Describe the Vascular Response in detail.
Inflammation is visible within seconds after vascular response is initiated. Arterioles near the injured area initially constrict, then vasodilation causes increased blood flow to the injured site. Increased blood flow and capillary permeability result in leakage of plasma from the vessels causing swelling in surrounding area. Increased blood flow and increasing concentration of red cells cause local warmth and redness. Biocemical mediators (histamin, bradykinins, leukotrienes, prostaglandins) stimulate the endothileal cells that line the capillaries and venules to retract allowing the tight junctions to open and let in the leukocytes and plasma into surrounding tissues. Once inside the plasma synthesis systems begin to prevent infection and further damage; limit and control the inflammatory process, elicit a more specific response; and prepare the area for healing.
Name the three plasma protien systems.
- Compliment system
- Clotting System
- Kinin System
How do the plasma protien systems work?
The systems are crucial for an effective immune response
They each play a unique role and when the first is activated the others are sequentially activated.
How is the complement system activated?
- Classical pathway -activated by (antibodies-antigen) response
- Lectin Pathway -activated by mannose containing bacteria
- Alternative Pathway- activated by gram negative bacteria and fungal cells
Activation of the complement system results in what?
Direct destruction of pathogens via:
- Opsonization- (tags microorganisms for destruction and allows phagocyte to attatch)
- Anaphylatoxin Activation-
- (induce mast cell degranulation,)
- Cell lysis
- C5-C9 form the membrane attack complex is a that create pores in the membranes of target cells allow water to pour in, leading to cell lysis and cell death.
- Leukocyte chemotaxis-
- drawing in WBC to the injured site or organism
**Starts killing right away once activated***
What is the compliment System?
Part of the Plasma protien system.
Destroys pathogens directly and most potent defender mostly against bacteria.
Destroys target cell membranes
Stimulates inflammation
Attract Phagocytes
Enhances Phagocytosis
In the Compliment Cascade, what do the complement protiens C1-C5 do and C5-C9
C1- initiates activities of classical pathway
C2- affects smooth muscles; promotes vasodilation & permeability
C3, C4, C5- anaphylatoxins (induce mast cell degeneration)
and release histamine.
C5- chemotactic factor to attract WBC.
C5-C9- form the membrane attack complex that bind to the lipid bilayer of cell membranes forming cylindrical channels (pores). These pores in the membranes of target cells allow water to pour in, leading to cell lysis and cell death.
What is the complement system responsible for?
Destroying pathogens directly.
Activates or collaborates with every other aspect of the inflammatory response.
What does the Clotting System do?
Forms a fibrounous mesh via FIBRIN at an injured or inflammed site to prevent the spread of infection.
- Stops bleeding.
- Helps prevent the spread of inflammation and infection.
- Keeps the invader near the site of injury, thus maximizing the access of inflammatory cells and proteins.
- Results in the formation of two peptides (fibrinopeptides A and B) that are released during the formation of fibrin and are chemotactic for neutrophils and increase vascular permeability
- Forms clot to Provides a framework for repair and healing
What is Chemotaxis?
Movement of an organism up a chemical gradient in response to a chemical stimulus.
Chemical signaling that causes leukocytes to move toward an area of inflammation. C3a and C5a are the complement components most involved in chemotaxis
Chemotactic factors attract the organism to move up the gradient to the specific destination.
***Attract the WBCs to the injured tissue site or inflammed area.
What are Cytokines?
Small proteins that signal cells. Different types function within immune response and play different roles.
What do Cytokines do?
Regulate innate and adaptive immunity by affecting other neighboring cells and telling them what to do.
Pro inflammatory or Anti inflammatory.
Each cytokine regulates differently depending on target cell with which it binds.
Include IL, Interferons, or and tumor necrosis factorsIL-10: antiinflammatory
TGF-B: antiinflammatory
What is the Kinin System?
Functions to activate and assist inflammatory cells by releaseing prostaglandis to cause dilation of vessels, smooth muscle contraction, increases vascular permeability, and increase leukocyte chemotaxis.
How does the Kinin system work to keep the inflammatory response confined?
Plasmin regulates clot formation by degrading fibrin and fibrinogen.
Hagement factor activates clotting cascade,
What is the primary prostaglandin released by the Kinin system and what does it do?
Bradykinin; causes dilation of blood vessel and stimulates nerve endings which induce pain.
What are Phagocytes?
Remove cellular debris and respond to invasion of foreign pahtogens.
Monocytes
Macrophages
Microphage- neutrophils and eosinophils
How do Phagocytes work?
Remove cellular debris and respond to invasion by moving thru diapedesis and exhibiting chemotaxis.
What is Diapedesis?
The passage of blood cells through the intact walls of the capillaries, typically accompanying inflammation.
What are interluekins (IL)?
Help regulate inflammation.
IL-1: Fever; activates phagocytes and lymphocytes
IL-6: helps with healing
Il-10 anti-inflammatory
WHat are two important chemotactic factors?
- Nuetrophil chemotactic factor- attracts nuetrophils to site.
- ECF-A- attracts eosinophils to the site of inflammation.
When are chemotactic factors released?
During Mast Cell degranulation
What are chemotactic factors?
Biochemical substances that attract luekocytes to the site of inflammation.
What is the role of memory cells regarding immunity?
They are long lived and capable of remembering the antigen and respond more rapidly after each exposures to the remembered antigen.
What is hypersensitivity?
What are the four types?
Is an altered immunologic response to an antigen that results in disease or damage to the host.
Is characterized by the immune mechanism.
Type I-IgE mediated
Type II-Tissue‐specific reaction(
Type III-Immune complex mediated
Type IV-Cell mediated • Delayed
How do memory cells in immunity create such a rapid response?
On reexposure, memory cells have the memory from previous exposure and do not require further differentiation they instead immediately become new plasma cells or effector T cells.
What are interferons?
Type of Cytokine. Serve to protect healthy cells from viral infection by stimulating the cellular production of antiviral proteins
Protects agians viral infections.
Modulates inflammatory response.
Produced and released by infected host
**Does not directly kill viruses but prevents them from infecting addtional healthy cells (Interferes)
What do INF-alpha and INF-beta do?
Induce production of antiviral protiens (Disrupt RNA synthesis)
Ex. Interferon is a tx for Hepatitis C; can also cure certain genotypes now.
What does INF-y do?
Increases the microbiocidal activity for macrophages.
How do INF-alpha and beta work?
They are released from infected host, attach to a receptor on a neighboring cell; if the neighbor is uninfected, they produce antiviral protiens to prevent other cells from becoming infected.
What is TNF-alpha?
A cytokine secreted by macrophages.
Produces local and systemic effects
Induces fever, increases proinflammatory proteins
Can causes muscle wasting and intravascular thrombus.
Probably responsbible for fatalities in shock related to gram negative bacteria bc TNF increases fever and gram negative thrive off of elevated temps.
What is opsonization?
Occurs during the compliment system to encourage the process of Phagocytosis.
The complement C3b and C5b (along with antibodies) make it easier for phagocytes to ingest bacteria.
Phagocytes have receptors on their surfaces for complement and antibodies and can thus “grab” onto the bacteria and pull them into the cell to be destroyed.
Allows the Macrophage to select and be able to phagocytize a pathogen.
What are the steps of Phagocytosis?
- Macrophage recognizes foriegn material thru opsonization
- The macrophage adheres to the foreign material to become a Phagosome.
- The Phagosome fuses with the lysosome to form a Phagolysosome
- The lysosome ingests the foriegn material, kills and digests and removes the cellular debris thru exocytosis.
What is the purpose of Margination in the inflammation process?
Alters the inside of the surface of the capillary allowing nuetrophils to stick/adhere to the capillary wall. Which then creates permeability by retraction of pores in vessel to allow the nuetrohpil to leak escape to the tissues.
How do Monocytes grow into Macrophages and how does this affect the inflammatory process?
Monocytes are produced in the bone marrow, they are released into the circulation and continue growing until they become Macrophages.
3-7 days after the nuetrophils (first defenders) arrive, the Macrophages arrive at the inflammatory site.
The process of phagocytosis begins upon Macrophage arrival.
What role do Eosinophils play in the inflammation response?
Nuetrophils and Eosinophils are primary phagocytes. Eosinophils are a weak phagocyte but do respond in large numbers during parasitic infection.
What is the First Line of defense?
Physical, Mechanical, and Biochemical Barriers.
- Physical: skin
- Mechanical: linings of the GI, GU, Resp tract (coughing, sneezing, urination, vomiting
- Biochemical: microbiomes
What is the Second Line of Defense?
The Inflammatory Response
What is the Third Line of Defense?
Acquired Immunity
The ability for the body to have memory and continue protecting the body with subsequent exposures.
Long term immunity
What is the classical pathway of the compliment system?
Antigin-antibody system
Activated by protiens of the adaptive immunity system (antibodies) bout to their specific targets (Antigen)
What is the Lectin Pathway in the Compliment System?
Activate by Mannose containing bacterial carbohydrates
What is the Alternative Pathway of the Compliment System?
Gram-activated by negative bacterial and fungal cell wall
Which pathway is most common form of Compliment System?
Classical Pathway (antigen-antibody)
Which Plasma Protien System releases Chemotactic Factors?
Compliment System
What happens with mast cell degranulation?
Inflammatory cytokines and chemotactic factors are released.
Attracts WBC (neutrophil & eosinophil) to inflammatory site
Cause vascular effects: increased permeability and vasodilation.
What are the three groups of active complement components and what do they do?
C3a and C5a – chemotaxis and degranulate mast cells (anaphylatoxins);
C3b and C5b – opsonize encapsulated bacteria;
C5-C9 – membrane attack complex.
What does the membrane attack complex do?
C5-C9 bind to the membranes of target cells and create pores through which water pours into the cells, leading to cell lysis and death.
