(I) Lecture 9: B cell Immunity Part II Flashcards

(28 cards)

1
Q

Primary functions of mature B-cells

A
  • detect pathogens/potentially harmful antigens
  • differentiate into plasma cells that secrete antibodies
  • create memory
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2
Q

How is B cell specificity changed?

A

Can ONLY change specificity of a B cell through gene rearrangement as a naive B cell

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3
Q

Does class-switching change specificity? Somatic hypermutations?

A

NO, neither change specificity

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4
Q

What antibody can be made without class-switching and hypermutations?

A

IgM

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5
Q

IgM

A
  • FIRST class produced by B cells (primary response)
  • low affinity antibodies as monomers
  • 10 binding sites as pentamers
  • mainly found in blood and lymph
  • can bind to different pathogens in planar or staple conformation
  • C1q binds to IgM to start complement cascade

neutralizes circulating pathogens and activates complement

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6
Q

IgG

A
  • most ABUNDANT antibody class in serum
  • LONG-lived
  • includes different classes
  • operates mainly in tissues
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7
Q

IgA

A
  • mainly present in SECRETION (MALT, saliva, mucus, tears, breast milk)
  • found in LOW levels in circulation
  • exists in monomer form but MAINLY in DIMERIC form in secretions
  • not a potent opsonin

neutralizes pathogens and toxins

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8
Q

IgE

A
  • mainly known for roles in ALLERGY and ASTHMA
  • made is SMALL quantities (has potent effects)
  • activates mast cells that secrete histamines (proinflammatory cytokines)
  • proposed role against parasites
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9
Q

IgD

A
  • minor immunoglobulin (only 0.2% of antigens)
  • most IgD remains bound to naive and memory B cells
  • main function: BIND ANTIGEN as BCR
  • higher in secretions of UPPER RESPIRATORY TRACT
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10
Q

When do adaptive immunity deficiencies typically show?

A

@ 9- 10 months old b/c that’s when adaptive immunity starts to kick in and they rely less on mother’s antibodies

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11
Q

What antibodies are passed through natural passive immunity?

A

IgA

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12
Q

Innate and Adaptive Immunity dynamics

A
  1. establishment of infection
  2. inductive phase (make cytokines)
  3. effector phase (T cells + plasma cells make ANTIBODIES)
  4. memory phase (all from adaptive immune cells)
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13
Q

Stages of immune response

A
  1. local infection and penetration of epithelium (immature DCs + macrophages eat pathogens and make cytokines)
  2. local infection of tissues
  3. lymphatic spread
  4. adaptive immunity
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14
Q

Antibody response

A

IgM kicks in earlier than IgG

IgG has higher levels in secondary response

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15
Q

Antibody response during vaccination

A

Unimmunized donor (Primary response)
- IgM > IgG
- low affinity of antibody
- low somatic hypermutation

Immunized donor (Secondary response)
- IgG, IgA
- high affinity of antibody
- high somatic hypermutations

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16
Q

Immunological memory and vaccines

A

Years after vaccine, the body is still making high levels of antibodies, especially IgG

making CD4 and CD8 memory cells as well but less than antibodies

17
Q

What immune components provide long term protection in vaccines?

A
  • memory effector T cells (CTL, Th1, Tfh)
  • memory B cells
  • long-lived plasma cells (IgG, IgA, antibodies)
18
Q

Herd immunity

A

when a large portion of population becomes immune, it decreases spread
- provides protection to susceptible individuals (elderly, immunocompromised, unvaccinated)

ONLY achieved when a large percentage of population is immunized

19
Q

Main approaches to making a vaccine

A
  • whole microbe
  • sub-unit (parts that trigger immune system)
  • next generation (just the genetic material)
20
Q

Whole microbe vaccines

A
  • can use inactivated vaccine “killed” or live-attenuated vaccine “not as virulent”
21
Q

Live attenuated vaccines

A

Type of whole microbe vaccine
STRONG response

  • microbe is made less infectious
  • strategies are used to weaken pathogenicity of microbe w/o affecting its antigenic potential
  • done through CELL CULTURING

Ex. MMR (mumps, measles, rubella), Polio, Yellow Fever

22
Q

Inactivated vaccines

A

Type of whole microbe vaccine
- weaker response

  • pathogen is killed using HEAT or CHEMICALS
  • must maintain its antigenic potential

Ex. cholera, hep A

23
Q

Subunits vaccines

A

SAFEST vaccine

  • made of purified antigens/toxins
  • microbes are grown in a lab and antigens are isolated and purified

Ex. DPT/Tdap

24
Q

Conjugate vaccines

A

Type of subunit vaccine

  • polysaccharide antigens do not induce T-cell immunity
  • B-cell response alone generates SHORT LASTING immunity
  • polysaccharide antigen is conjugated w/ a protein vaccine to induce BOTH T-cell and B-cell immunity

Ex. meningococcal vaccine

25
Next Gen vaccines
- uses "next gen" techniques like DNA manipulation and mRNA vaccines
26
HPV vaccine
Human Papilloma Virus L1 capsid protein self assembles into virus-like particles but contain no viral genetic materia - empty on the inside ZERO risk of infection
27
What kind of vaccine is COVID vaccine?
mRNA vaccine mRNA encodes spike protein of virus
28
Correlation and Causation
Correlation does not mean causation Ex. Just because MMR vaccine is typically given around time of autism diagnosis does NOT mean that it causes autism