Lecture 10 9/19/23 Flashcards

1
Q

What are the three types of antigen presenting cells?

A

-dendritic cells
-macrophages
-B cells

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2
Q

What are the steps of B cells acting as APCs?

A

-B cell binds bacteria
-bacterial particle is internalized, degraded, and presented on MHCII
-peptide on B cell MHCII is presented to helper T cell
-B cell is activated to differentiate into plasma cell and produce antibodies

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3
Q

How do B cells capture antigens for presentation?

A

through their BCRs

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4
Q

Which blood tube is used to collect serum?

A

red tops

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5
Q

Where is the highest concentration of antibodies found?

A

serum

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6
Q

Why are antibodies called immunoglobulins?

A

on serum electrophoresis, the majority of antibodies are found in gamma globulins

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7
Q

What are the effector functions of antibodies?

A

-block ability of microbes to infect host cells
-inhibit spread of microbes
-inhibit pathologic effects of toxins

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8
Q

What are the components of antibodies?

A

-two identical heavy chains
-two identical light chains

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9
Q

What are the two regions of an antibody?

A

-variable region
-constant region

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10
Q

What is the responsibility of the variable region?

A

binding to specific antigens at the antigen-binding site/paratope

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11
Q

What is the responsibility of the constant region?

A

complement activation through the classical pathway

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12
Q

What are the two antibody fragments?

A

Fab and Fc

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13
Q

What does the Fab fragment contain?

A

antigen-binding site

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14
Q

What does the Fc fragment contain?

A

complement-activating site

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15
Q

What fragments are produced by papain?

A

-2 Fab fragments
-1 Fc fragment

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16
Q

What is the hinge region?

A

a stretch of heavy chains between the Fab and Fc fragments

17
Q

What is the function of the hinge region?

A

to provide segmental flexibility

18
Q

What are the antibody types?

A

-IgG
-IgM
-IgA
-IgE
-IgD

19
Q

What heavy chain genes are associated with each type of antibody?

A

-IgG: gamma
-IgM: mu
-IgA: alpha
-IgE: epsilon
-IgD: delta

20
Q

What are the two types of light chain?

A

-kappa light chain
-lambda light chain

21
Q

Which chain determines immunoglobulin type?

A

heavy chain

22
Q

What are the characteristics of IgG?

A

-most abundant antibody in bloodstream
-Y shape
-only antibody that can cross placenta
-neutralizes toxins and microbes
-activates classical complement pathway

23
Q

What are the characteristics of IgM?

A

-five subunits and J chain form a pentamer
-one of the first antibodies produced
-more efficient than IgG at complement activation and microbial clearance
-too large to enter inflammatory sites and cross placenta

24
Q

What are the characteristics of IgA?

A

-produced on mucosal surfaces
-important in response to intranasal and oral infections and vaccinations
-prevent attachment of pathogens to mucosal epithelial cells
-forms a dimer from two subunits and J chain
-addition of secretory component forms secretory IgA
-secretory component protects IgA from digestion
-does not activate complement

25
Q

What are the characteristics of IgE?

A

-extremely small amounts in blood
-Y shape
-responsible for immunity to parasites and allergies
-bind tightly to mast cell and basophil receptors

26
Q

What are the characteristics of IgD?

A

-remain attached to B cells
-very little released in blood
-Y shape

27
Q

What is unique about bovine immunoglobulins?

A

-very long variable domain that folds into ball and stalk structure
-ball structure is highly variable and binds to antigen

28
Q

What is unique about camel and llama IgG?

A

there are three subtypes (IgG1, IgG2, and IgG3)

29
Q

What is unique about camel IgG2 and IgG3?

A

only have heavy chains, no light chains

30
Q

What is unique about just camel IgG2?

A

very long hinge region