Intro to Immunology

Question 1

7 main concepts of Immunology

Answer 1

1. balance between hypo and hypersensitivity
2. two overlapping compartments: innate vs adaptive
3. antigen specificity of adaptive IS is due to presence of antigen-specific receptors
4. antigen receptors have tdiversity that is regulated through VDJ recombination
5. specific and adaptive immune responses are activated and expanded by clonal selection
6. adaptive immune system has a memory
7. immune system tightly regulated

Question 2

balance between hypo and hyperreactivity

Answer 2

• hyporeactivity=immunodeficiency
  
  • congenital or acquire
  • immunse senescence
  • resulting from treatment (chemo)
  • malnutrition
  • malignancies
  • trauma/stress
• hyperreacticity=immunopathology (septic)
  
  • systemic autoimmunity
  • organ specific
  • allergies/asthsma
  • immunopathology

Question 3

Ex. Acquire Immunodeficiency

Answer 3

Kaposi’s Sarcoma- from human herpes virus-8

Those with HIV have depletion of CD4 T cells leaving them susceptible to infection with herpes virus and disease therefor kaposi’s sarcoma

Question 4

innate and adaptive immune systems

Answer 4

innate: early line of defense against microbial infections. non specific effectors
adaptive: occurs as a response to infection. specific responses to microbial antigens. effective at clearing but not perventing

Question 5

Innate IS

Answer 5

primitive

elements are always presently active, constituitively active

nonspecific

magnitude in kinetics are the same every single time (every time you are exposed, response is the same)

Question 6

Components of innate IS

Answer 6

physical barriers

protective secretions

phagocytic cells

enzymes

components of the complement system

cytokines

Question 7

Adaptive IS

Answer 7

only in vertebrates

must be induced

highly specific to antigens derived from microbes

has memory-responds differently after subsequent exposures

can usually distinguish between self and non self

Question 8

components of adaptive IS

Answer 8

antigen presenting cells

B cells

T lymphocytes

cytokines

Question 9

Antigenic specificity due to antigen specific receptors

Answer 9

B cells - antigen binding–>secretion of antibodies specific for antigen

T cells-binding to peptide presented by an APC–>antigen specific effector T Cell

Question 10

Diversity through VDJ recombination

Answer 10

• lots of antigen specific lymphocytes
• B and T recognize 10^7-10^9 distinct determinants
• diversity is the result of variability of structures of antigen binding sites of lymphocyte receptors
• VDJ helps encode these

Question 11

VDJ recombination

Answer 11

rendom recombination allows encoding of huge number of antigen receptors

Question 12

Clonal selection

Answer 12

• every lymphocyte has different specificity, some will never see an antigen and die, but some will find their specific antigen and divide and expand and differentiate and make more antibodies specific for what they encountered.
• allows for enrichment for cells specific for common pathogens circulating through body

Question 13

Adaptive immune system memory

Answer 13

response much greater after first exposure

infection is race between pathogen and IS

IS has kinetic advantage, can often control infection

underlies effectiveness of vaccines

B cells can divide into memory B cells

Question 14

IS is tightly regulated

Answer 14

central tolerance-elimination of self reactive cells during development

peripheral tolerance-variety of mechansims that prevent activation of self-reactive cells that escape central tolerance