15: Humoral Immunity Flashcards

1
Q

Follicular vs marginal B cells

A

Follicular: recirculating (majority)
Marginal: in spleen for blood-borne Ags

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2
Q

What causes B cells to undergo anergy

A

B cell recognizing Ag without BCR cross linking, co-stimulatory ligands, or cytokine support

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3
Q

What is critical for class switching and affinity maturation to occur?

A

CD40-CD40L interaction

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4
Q

Where do affinity maturation and class switching occur?

A

GCs

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5
Q

Class switching process: 2 steps

A
  1. Th and Tfh cell cytokines open switch regions in heavy chain DNA
  2. VDJ gene segment recombined with downstream C region gene
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6
Q

Affinity maturation

A

AID introduces point mutations in switch regions of variable and light Ig genes -> high affinity Abs

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7
Q

High affinity selection checkpoint after affinity maturation

A

FDCs provide Ags to new BCR receptor to sample -> if higher affinity, B cell clone is selected for further differentiation

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8
Q

Where are long lived plasma cells found?

A

Bone marrow (IgG), mucosa (IgA)

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9
Q

Plasma cells: what cell marker increases

A

CD27

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10
Q

Anti-apoptotic marker on memory B cells

A

Bcl-2

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11
Q

What cytokine signal is required to keep memory B cells alive?

A

IL-7

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12
Q

Antibody feedback

A

Excess Abs bound to a pathogen will block further Ab production

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13
Q

Microbe neutralization: classes and purpose

A

Done by all Ig classes, neutralizes the infectivity of a pathogen + block pathogens from binding cell surfaces to gain entry

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14
Q

Which Ig is a super efficient complement fixer?

A

IgM

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15
Q

Waste management function of Abs

A

Opsonization -> clearance of ICs from circulation in a non-inflammatory manner

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16
Q

How RBCs play a role in waste management

A

CR1 on erythrocytes bind circulating ICs -> liver/spleen -> removal of ICs and digestion by phagocytes -> RBCs continue to circulate

17
Q

ADCC: four cell types that perform it

A

NK cells, macrophages, neutrophils, eosinophils

18
Q

ADCC

A

IgG or IgE bind surface-bound Ag -> NK cell binds Ab via Fc receptor and kill via lytic enzymes, TNF, and perforin/granzymes

19
Q

What class does Th2 cytokines influence class switch to?

A

IgE

20
Q

Cells that produce natural Abs against blood group Ags

A

B1 cells, marginal zone B cells

21
Q

FcRN

A

Neonatal IgG receptor for recycling and transcytosis of IgG across placenta

22
Q

How maternal IgG crosses placenta

A

IgG pinocytosed from circulation -> bound to FcRN in endosome -> translocates to fetal circulation and releases when at neutral pH

23
Q

Most vulnerable period for an infant’s immune system

A

6-12 months

24
Q

Passive immunization

A

Introduction of Abs or antiserum into a naive recipient

25
Q

Difference between passive and active immunization

A

Passive: immediate, no memory
Active: lag time, makes memory

26
Q

Functions of passive immunization

A
  1. Prevent disease after known exposure
  2. Ameliorate sx of ongoing disease
  3. Protect immunosuppressed pts
  4. Block bacterial toxins
27
Q

IVIG uses

A

Treatment of some autoimmune and inflammatory diseases

28
Q

Monoclonal Abs

A

Highly specific epitope recognition -> stimulates a variety of immune responses -> come with side affects

29
Q

Uses of monoclonal Abs

A

Cancers, autoimmune diseases