Immuno 4 Flashcards

1
Q

all antibodies are of a class of protein called

A

immunoglobulin

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2
Q

structure of an immunoglobulin

A

4 polypeptide chains bound together by disulfide bonds

2 light chains, 2 heavy chains

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3
Q

what are the 2 regions of the immunoglobulin

A

variable and constant region

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4
Q

variable region of an immunoglobulin

A

(also called FAB- fragment antigen binding)
-the end of the immunoglobulin and the one that forms the structure that will bind to a specific antigen (fingers), variations

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5
Q

constant region of an immunoglobulin

A
  • backbone that doesn’t have as many variable combinations (only varies from one class to another)
  • (also called fragment Fc region)
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6
Q

5 immunoglobulins and percentages

A
  1. IgG - 80%
  2. IgA - 15%
  3. IgM - 5%
  4. IgD - 0.2%
  5. IgE - 0.002%
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7
Q

where is IgG usually found

A

epithelial tissue such as skin and conjunctiva of the eye

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8
Q

IgG is primarily responsible for

A

fixation of complement and opsonization

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9
Q

IgG is the principle source of ____ immunity against organisms in _____ space

A

humoral immunity against organisms in extravascular space

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10
Q

IgA is associated with ___ tissue

A

epithelial

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11
Q

what is IgA in the blood stream versus in the tissue

A

blood: monomer
tissue: dimeric

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12
Q

what is secretory IgA

A

is after dimer and secretory component are added

-it bathes epithelial tissue

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13
Q

how does secretory IgA work?

A

it inhibits virus particles from sticking on from epithelial surface- “it slides off like teflon paint”

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14
Q

in secretory IgA, what forms the monomers and what connects them to make a dimer

A

monomers are produced by lymphocytes

-dimer formed from connections from J chain

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15
Q

a unique feature of IgM is its

A

high molecular weight

5 monomers

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16
Q

IgM is especially efficient at

A

fixing complement (at attaching complement once it is activated to the invading organism)

17
Q

what immunoglobulin is “first at the scene” at the site of infection

18
Q

role of IgM is protecting _____ space

A
intravascular space 
(blood vascular system inside the vessels)
19
Q

IgD

A

nearly all IgD appears on the surface of lymphocytes (like IgM does too)- so could be related or coordinated with IgM

20
Q

IgE is also called the

A

“skin sensitizing antibody”

21
Q

IgE normally has a physiological role to

A

protect mucosal surfaces

22
Q

IgE triggers release of certain agents that start inflammation response such as

A
  • vasodilation of blood vessels

- chemotactic factors which attract macrophages

23
Q

what is an allergy (hypersensitivity)?

A

an exaggerated immune response

24
Q

type I hypersensitivity is also known as

A

immediate Rx, anaphylaxis

25
what occurs during initial exposure during type I hypersensitivity ?
B cells -> plasma cells, plasma cells produce type of IgE called reagin which binds to mast cells
26
what occurs during second exposure during type I hypersensitivity ?
allergen binds to IgE, destabilizing the cell membrane which bursts (if the allergen bridges two IgE molecules) -explosive degranulization releases components from mediators
27
explosive degranulation causes the mediators to release :
- histamine - heparin - prostaglandins - proteolytic enzymes
28
the mix of mediators in type I hypersensitivity causes
- smooth muscle contraction - vasodilation (redness) - increased vascular permeability (tissue starts to lose fluid) - mucous secretion (causing hay fever symptoms)
29
what occurs with the mast cell in immediate hypersensitivity?
all those packets of mediators inside the mast cells blow up and released all at once
30
what occurs in systemic anaphylaxis
release of a bunch of mast cells throughout the body: -smooth muscle contraction and bronchioles constrict -arterioles dilate, drastically reducing blood pressure -permeability of the vessels increases and they start losing fluid (shock)
31
what occurs during localized anaphylaxis
localized release of mediators- often in mucous membrane, resulting in hay fever -if in lower respiratory tract, bronchial asthma (deeper and airborne)
32
type IV hypersensitivity is also called
cell-mediated, delayed
33
what occurs during onset on type IV hypersensitivity
subset of T lymphocytes called delayed type hypersensitivity cells (TH1) recognize antigen, react, and release cytokines which can cause tissue damage
34
process during type IV hypersensitivity
- T lymphocytes recruited via cytokines - cytokines increase capillary permeability: macrophages have exaggerated response (tissue damage) - special T cells amplify the whole thing
35
why is it called delayed hypersensitivity
the whole process for T cells to proliferate, send out cytokines, and recruit macrophages can take a day or two
36
type IV hypersensitivity is involved in what pathologies
- autoimmune diseases - transplant rejection - killing cancer cells - contact dermatitis
37
what is contact dermatitis
occurs with certain products (cosmetics, TPAs, metals) | -it is an immune reaction to something that isn't biologic
38
how can contact dermatitis illicit an immune response
small molecules called haptens when attached to a carrier (protein in the skin)- this combination is antigenic