Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CGIER II > CGIER 21 - Immune System > Flashcards

CGIER 21 - Immune System Flashcards

1
Q

Humoral (Antibody Mediated) immunity is a function of…

A

B-lymphocytes
(immunological competence probably develops in the bone marrow)
- Immunologically competent B-lymphocytes move to lymphoid tissues (mainly the lymph nodes and spleen)
- B-lymphocytes tend to be found in separate areas of lymphoid tissue from the T-lymphocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Antibodies (Immunoglobulins) Structure

A
  • Highly specific Y-shaped protein
  • 4 polypeptide chains:
    2 identical heavy (400+ AAs) + 2 identical light (214 AAs)
    (one light chain covalently bound to each heavy chain, two heavy chains covalently bound to each other)
  • Each chain has a constant C-region, and a variable V-region
  • 5 Ig classes recognized based on AA sequence of heavy chain at C region
  • V region has 3D shape which binds to appropriate antigen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Antigen

A

Molecule which generates immune response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Epitopes

A

Antigenic determinant regions recognized by antibodies as a point of binding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

5 Immunoglobulin Classes

A
  • IgG
  • IgM
  • IgA
  • IgD
  • IgE
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

IgG

A

75% of plasma
Binds to macrophages, neutrophils
Secondary response
Activate complement system
Effective against bacteria, viruses, cross placenta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

IgM

A

Pentamer - 5 IgG molecules connected, giving 10 antigen binding sites in 1 molecule
Potent agent of precipitation
Blood type - primary response
Elevated IgM tells us patient recently infected
Activate complement system, agglutination, precipitation
Effective against bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

IgA

A

Body secretions (mucus, saliva, tears, milk)
Dimer - 2 AB units
Effective against viral/bacterial attachment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

IgD

A

On B-lymphocyte surface
Rarely secreted
Effective against B-cell receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

IgE

A

Bound to mast cells and Basophils
Activate allergic response, anaphylactic response
Effective against parasitic worms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Antibody Action

A
  1. Direct Action (agglutination, precipitation, neutralization)
  2. Activation of Complement system
  3. Activate anaphylactic system (try to prevent this)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Direct Action (antibody system 1)

A
  1. Agglutination - clumps antigenic agents on cells together
  2. Precipitation - soluble antigen becomes insoluble, precipitates out
  3. Neutralization - antibodies bind to specific sites on bacterial exotoxins, inhibiting their action, or on viral surface antigens, inhibiting their attachment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Complement System

A

3 pathways: Classical, Lectin, Alternative
20 soluble proteins form complex
Cascade of proteolytic cleavage reactions activate downstream components
IgM and IgG antibodies form antigen-antibody complexes, activate first component (C1) of the complement system
Resulting in number of active proteins
Not antigen specific
Build structure on bacterial cell wall, able to cause lysis and bursting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Actions of Complement System (antibody system 2)

A
  1. Lysis - direct lysis of pathogen cell membrane (MAC attack generates hole in pathogen cell membrane)
  2. Opsonization - coating pathogen, allows phagocytosis by macrophages/neutrophils
  3. Chemotaxis - attracts neutrophils and macrophages to area
  4. Inflammation - increase local reaction by stimulating histamine release
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Activation of Anaphylatic System (antibody system 3)

A

IgE attach to mast cells (in tissues) and basophils (in blood)
When antigen reacts with exposed IgE causes cell to enlarge, rupture, release histamine
Causes local vasodilation, inflammation, attracts other elements of immune system to the area

Some individuals show extreme systemic response from basophils in the blood system - allergy
Allergens are usually drugs, venoms, foods
histamine and other chemicals released in vast quantities causing extreme vasodilation and capillary permeability
Severe constriction of bronchioles, rapid loss of BP, anaphylactic shock, death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Activation of B-cells

A
  1. Phagocytic cell (macrophage, neutrophil) engulfs a pathogen, degrades it, presents some of its peptides on the surface of teh APC in complex with MHC
  2. Inactive T-helper cell (specific for antigen) interacts with MHC-peptide complex on APC surface, becomes activated
  3. Inactive B-cell (specific for antigen) interacts with antigen via B-cell receptor, antigen is engulfed, portions displayed on surface of B-cell in complex with MHC
  4. Activated T-helper cell interacts with MHC-antigen complex on B-cell surface
  5. Interaction stimulates T-cell to activate B-cell via release of various cytokines
17
Q

Once activated, B-cells…

A

Increase in size, divide, differentiate to plasma cell and memory cells
Plasma cells remain in lymph nodes, produce and release antibodies
B-cell produces only 1 specific type of idiotope of an antibody
B-memory cells continue to produce small amounts of antibody for many years
They also show the same secondary response as T-memory cells

18
Q

Allergy

A

Exaggerated/inappropriate immune response initiated by exposures to antigen
People with allergic tendency to produce antibodies against mild antigens - allergens, do not elicit response in non-allergenic individuals (seems to be genetic disposition)

About 20% of pop show allergic disorder (asthma, hay fever, food allergy) due to malfunction of normal immune response

19
Q

Allergic Rhinitis - Sensitization (1st step)

A
  • Degraded allergen (pollen) is presented by an APC to a T-cell, activated, differentiates into T-cell subsets
  • TH2 cells release interleukin 4, upregulates B cells to produce IgE, binds to mast cells, basophils
  • Subsequent exposure, memory cells from first exposure produce a much stronger response
20
Q

Allergic Rhinitis - Activation (2nd step)

A

-Activation of mast cell
- Further exposure to aerial pollen grains stimulates more IgE antibody release from sensitized plasma cells in nasal mucosa
- IgE attaches to mast cells by C-region
- Pollen combines with V-region, causes release of histamine/seratonin/etc from mast cell
- Dilate capillaries causing oedema, inflammation, sneezing, running nose, vasodilation, constriction of respiratory passageways

21
Q

Vaccination

A

Secondary response more powerful than primary, may even prevent symptom development
Vaccination = deliberate exposure of immune system to antigen in order to generate memory cells and antibodies
(antigen used for vaccination will not be active pathogen, but may be:
- killed pathogen
- attenuated pathogen
- non-pathogenic strain
- coat protein derived from pathogen
- altered non-toxic bacterial toxin)

CGIER II (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions