Exam 1 --Ch 1 (intro), Ch 2 (Innate system) Flashcards
Ch.1 : What is Immunity? Ch. 2: The Innate System
What is hematopoiesis? What does it start with? And what can that become?
the formation of new blood cells; starts with Hematopoietic stem cells that can become either a Myeloid Progenerator or a Lymphoid Progenerator
What can a Lymphoid Progenerator become?
B cells, T cells, and NK cells, and dendritic cells
What can a Myeloid Progenerator become?
Dendritic cells (macrophages, monocytes), Neutrophil, eosinophil, basophil, mast cell, platelets, erythrocyte
What are the three “levels” of protection?
physical barrier, innate immunity, adaptive (specific) immunity
What are some physical barriers?
- skin (low pH, high salt)
- Mucosa and mucus
- urine and feces
- saliva
- tears
- ciliary escalator
- normal microbia
What are the Innate System components?
- stuff you are born with!
- some WBCs (macrophages, neutrophils)
- Complement System
- inflammation
What are the two primary cells that are major components of Adaptive Immunity? And what do they do and where do they mature?
B cells– when activated produce antibodies (mature in bone marrow)
T cells–helper, killer, regulatory (mature in thymus)
Compare the Innate vs Adaptive Responses:
- Response Time
- Specificity
- Response to repeat infection
- Major components
- Innate: minutes to hours; Adaptive: days
- Innate: limited and fixed; Adaptive: highly diverse, adapts to improve during course of response
- Innate: same each time; Adaptive: more rapid and effective with each subsequent exposure
- Innate: barriers (skin), phagocytes; Adaptive: T and B lymphocytes, antigen-specific receptors, antibodies
What are the key steps of Phagocytosis? (4)
Phagocytes migrate to a site of infection and can destroy the infecting bacteria:
- chematoxis
- adherence
- ingestion
- digestion
What are the 7 specific steps to Phagocytosis?
- chemotaxis and adherence of microbe to pahgocyte
- ingestion of microbe by phagocyte
- formation of a phagosome
- fusion of phagosome with a lysosome to form a phagolysosome
- digestion of ingested microbe by enzymes
- formation of residual body containing indigestible material
- discharge of waste materials
Compare antigen vs immunogen
Antigen (Ag) = anything that is foreign to the body
Immunogen = something that causes immune response
**all antigens are immunogens, but NOT all immunogens are antigens)
What are the actions of:
- T helper cells
- T killer cells
- T regulatory cells?
- quarterback–doesn’t kill anything, but regulates system
- intracellular pathogens
- maintain homeostasis
What is the antigen binding region of the antibody called?
Fab
What is the stem region of the antibody called?
Fc
What can occur when the immune system doesn’t function correctly?
- overly active or misdirected immune responses
- immunodeficiency
- transplantation
- cancer
What are the primary lymphoid organs?
thymus and bone marrow
What are the secondary lymphoid organs?
What occurs there?
- lymph nodes
- spleen
- muscosa (ass. lymphoid tissue)
- other diffuse and loosely organized areas
Areas where lymphocytes encounter antigen
How are secondary lymphoid organs connected?
via the blood and lymphatic circulatory systems
What part of the body does the right lymphatic duct drain? What drains the other part of the body then?
right side of head, chest, and arm
Thoracic duct drains rest of body
Where are Pattern recognition receptors? What about Pathogen associated molecular patterns?
PRR – on WBC
PAMP– on pathogen
What is included in the innate system? (5)
- Existing from birth
- Complement Proteins
- Professional Phagocytes
- Natural Killer Cells
- Antimicrobial Molecules
What is the complement system?
a group of serum proteins made by liver
Once the complement system is activated what are the possible outcomes? (4)
- membrane lysis
- chemotaxis
- inflammation
- opsonization
What are the 3 activation pathways of the complement system?
- Classical pathway
- Lectin pathway
- Alternative pathway
What initiates the classical pathway of the complement system? Then what occurs first?
the antibody binding; IgM or IgG binds to a multivalent antigen –> this alllows binding of C1q, C1r, C1s complex
What are the steps of the classical pathway of the complement system?
- C1 binds antigen-bound antibody
- C1 then cleaves C4 into C4a and C4b, followed by C2 into C2a and C2b
- C4b2a binds to cell surface C3 convertase is created
- C4a and C2b are liberated
- C3 convertase cleaves C3 into C3b and C3a, C3a liberated
- Some C3b combines with C3 convertase to form C5 convertase (C4b2a3b)
- Some C3b opsonizes bacterial cells
What initiates the lectin pathway of the complement system?
when soluble proteins recognize microbial antigens
What are the steps of the lectin pathway of the complement system?
- Lectins bind to microbial surface carbs
- Lectins serve as docking site for MBL-ass. serine proteases (MASPs)
- MASPs cleave C4 and C2 to form C3 convertase (C4b2a)
- some C3b combines with C3 convertase to form C5 convertase (C4b2a3b)
What initiates the alternative pathway of the complement system?
several ways; small amounts of C3 are always being cleaved and activated C3b binds to membrane of target cell
What are the steps of the alternative pathway for the complement system?
- Factor B binds and is cleaved by Factor D
- On the membrane is C3 convertase (C3bBb)
- C3 convertase is stabilized by Properdin and it cleaves more C3 proteins
- Newly activated C3b binds to C3bBb to form C5 convertase (C3bBbC3b)
- C5 convertase cleaves many more C5 proteins
When do the three complement pathways converge?
at formation of C5 convertase
What does C5 of the complement system initiate? What occurs?
generation of Big MAC attack
- deposition of C5b, C6,C7,C8, and C9 on target cell membrane
- = a pore structure that disrupts osmotic integrity and cause cell death
What are the C3 convertase combinations for all three pathways of the complement system?
- Classical – C4b2a
- Lectin – C4b2a
- Alternative – C3bBb
What are the C5 convertase combinations for all three pathways of the complement system?
- Classical – C4b2a3b
- Lectin – C4b2a3b
- C3BbC3b