4. Immunology (2)

Question 1

Adaptive immunity cells need _____ presented to them.

Answer 1

antigens

Question 2

What are MHC Class 1 molecules? (2)

Answer 2

• MHC I are present on all NUCLEATED cells in our body.
• Typically, white blood cells have lots of MHC I, hepatocytes less, and red blood cells almost none (probably why malaria finds refuge in them).

Question 3

What are MHC Class 2 molecules?

Answer 3

MHC II are found ONLY on specialized antigen presenting cells = B lymphocytes, dendritic cells, macrophages.

Question 4

What is extracellular bacteria?

Answer 4

Question 5

What is the process of exocytosis?

Answer 5

Question 6

What is the function of MHC Class 1 molecules? (4)

Answer 6

Question 7

What is the function of MHC Class 2 molecules? (3)

Answer 7

Question 8

How do MHC II molecules and B cells assist Helper T cells to produce cytokines? (3)

Answer 8

Question 9

Antibodies have TWO functions done by 2 separate parts of the antibody molecule:

Answer 9

1. Recognition of antigen (antigen binding site) by the variable region
2. Effector function is done by the constant region

Question 10

B-cell receptor does not have these effector functions because the C region is buried in the membrane —>

Answer 10

its role is to activate B cells.

Question 11

The different suffixes of the antibody isotypes denote the different types of heavy
chains the antibody contains, with each heavy chain class named alphabetically: α
(alpha), γ (gamma), δ (delta), ε (epsilon), and μ (mu). This gives rise to : (5)

Answer 11

IgA, IgG, IgD, IgE, and IgM.

Question 12

Mature Naïve B-cells (those that have not encountered their antigen) express ____ and ____ on their surface.

Answer 12

IgM
IgD

Question 13

When they encounter their antigen and are activated class switching occurs. Class switching is the process whereby an activated B cell changes its antibody production from IgM to either___,____, or _____ depending on the functional requirements.

Answer 13

IgA, IgG, or IgE

Question 14

In the end, most of our Ig are represented by ____.

Answer 14

IgGs

Question 15

Activation of B cell results in: (3)

Answer 15

• Clonal proliferation
• Secretion of IgMs
• Ig Class switching from IgM to IgG or IgE or IgA

Question 16

Fill in the arrows.

Answer 16

C1
IgG and IgM

Question 17

What is the classical complement pathway?

Answer 17

Question 18

What is the C1- inhibitor? (4)

Answer 18

• C1-inhibitor is an acute-phase protein that circulates in blood.
• The levels rise ~2-fold during inflammation.
• It stops the classical pathway.
• It also limits spontaneous activation of C1 in the plasma.

Question 19

What is the result of the deficiency of the C1-inhibitor? (2)

Answer 19

• Deficiency of this protein is associated with hereditary angioedema (“hereditary angioneurotic oedema”), or swelling due to leakage of fluid from blood vessels into connective tissue.
• Deficiency of C1-inhibitor permits localised vasodilation and increased vascular permeability. In its most common form, it presents as marked swelling of the face, mouth and/or airway that occurs spontaneously or to minimal triggers (such as mild trauma), but such swelling can occur in any part of the body. In 85% of the cases, the levels of C1-inhibitor are low, while in 15% the protein circulates in normal amounts but it is dysfunctional.

Question 19

What is the result of the deficiency of the C1-inhibitor? (2)

Answer 19

• Deficiency of this protein is associated with hereditary angioedema (“hereditary angioneurotic oedema”), or swelling due to leakage of fluid from blood vessels into connective tissue.
• Deficiency of C1-inhibitor permits localised vasodilation and increased vascular permeability. In its most common form, it presents as marked swelling of the face, mouth and/or airway that occurs spontaneously or to minimal triggers (such as mild trauma), but such swelling can occur in any part of the body. In 85% of the cases, the levels of C1-inhibitor are low, while in 15% the protein circulates in normal amounts but it is dysfunctional.

Question 20

Primary immune response vs Secondary immune response

Occurrence:

Answer 20

Question 21

Primary immune response vs Secondary immune response

Response:

Answer 21

Question 21

Primary immune response vs Secondary immune response

Response:

Answer 21

Question 22

Primary immune response vs Secondary immune response

Lag phase:

Answer 22

Question 23

Primary immune response vs Secondary immune response

Antibody level:

Answer 23

Question 24

Primary immune response vs Secondary immune response

Antibody produce:

Answer 24

Question 25

Primary immune response vs Secondary immune response

Antibody level:

Answer 25

Question 26

Primary immune response vs Secondary immune response

Affinity:

Answer 26

Question 27

What are the protective mechanisms of binding antibodies to antibodies? (5)

Answer 27

Question 28

What is neutralization? (3)

Answer 28

• Both viruses and bacterial toxins must bind to the plasma membranes of body cells before they can enter or injure those cells.
• Binding occurs at superficial sites on the bacteria or toxins.
• Antibodies may bind to those sites, making the virus or toxin incapable of attaching itself to a cell.

Question 29

What is Precipitation and agglutination? (4)

Answer 29

• If antigens are close together, an antibody can bind to antigenic determinant sites on two different antigens.
• In this way, antibodies can tie large numbers of antigens together, creating an immune complex.
• When the target antigen is on the surface of a cell or a virus, the formation of immune complexes is called agglutination.
• Agglutination enhances phagocytosis and reduces the number of infectious units to be dealt with.

Question 30

What is the Prevention of pathogen adhesion? (2)

Answer 30

• Antibodies dissolved in saliva, mucus, tears and sweat coat epithelia, providing an additional layers of defense.
• A covering of antibodies makes it difficult for bacteria or viruses to adhere to and penetrate body surfaces.

Question 31

What is the activation of complement? (2)

Answer 31

• Upon binding to an antigen, portions of the antibody molecule change shape, exposing areas that bind complement proteins.
• The bound complement molecules then activate the complement system, which destroys the antigen.

Question 32

What is opsonization? (3)

Answer 32

• Phagocytes can bind more easily to antibodies and complement proteins on the surface of a pathogen than they can to an antibody-free and complement-free surface.
• As a result, a coating of antibodies and complement proteins on a pathogen increases the effectiveness of phagocytosis.
• Some bacteria have slick plasma membranes or capsules, and phagocytes must be able to hang onto their prey before they can engulf it.

Question 33

What is the attraction of phagocytes?

Answer 33

• Antigens covered with antibodies attract eosinophils, neutrophils and macrophages – cells that phagocytize pathogens and destroy foreign or abnormal plasma membranes.

Question 34

What is the stimulation of inflammation?

Answer 34

• Antibodies may promote inflammation by stimulating the release of chemicals from basophils and mast cells.

Question 35

What is the stimulation of inflammation?

Answer 35

• Antibodies may promote inflammation by stimulating the release of chemicals from basophils and mast cells.

Question 36

IgG:

Answer 36

Question 37

IgM:

Answer 37

Question 38

IgA:

Answer 38

Question 39

IgD:

Answer 39

Question 40

IgE:

Answer 40

Question 41

What is an allergy?

Answer 41

Hypersensitivity reaction mediated by immunological mechanisms

Question 42

An allergy is an immune reaction to something that does not affect most other people. Substances that often cause reactions are:

Answer 42

• Pollen
• Dust mites
• Mold spores
• Pet dander
• Food
• Insect stings
• Medicines

Question 43

What processes take place during an allergic reaction?

Answer 43

Question 44

How are airways affected during an allergic reaction? (3)

Answer 44

• Decrease in airway diameter and an increase in mucus secretion.
• Congestion and blockage of the airways (wheezing, coughing, phlegm)
• Swelling and mucus secretion in nasal passages

Question 45

What is Anaphylaxis? (4)

Answer 45

• exaggerated allergic response to a substance to which an individual is hypersensitive.
• it typically results in a number of symptoms including an itchy rash, throat swelling, and low
  blood pressure.
• common causes include insect bites, foods, and medications.
• rapidly fatal, therefore requires an immediate injection of adrenaline to relax smooth muscle and inhibit the cardiovascular effects of anaphylaxis.

Question 46

After transmission of HIV to a new host: (3)

Answer 46

Question 47

How does HIV eventually develop to AIDS?

Answer 47

Question 48

Deficit in CD4 T helper cells (mainly) and CD8 T cytotoxic cells due to: (4)

Answer 48

Question 49

HIV infection weakens your immune system, making you much more likely to develop many infections and certain types of ______.

Answer 49

cancers

Question 50

Infections common to HIV/AIDS: (6)

Answer 50

Question 51

Cancers common to HIV/AIDS: (3)

Answer 51

• Lymphoma. This cancer starts in the white blood cells. The most common early sign is painless swelling of the lymph nodes in your neck, armpit or groin.
• Kaposi’s sarcoma. A tumor of the blood vessel walls, Kaposi’s sarcoma usually appears as pink, red or purple lesions on the skin and mouth.
• HPV-related cancers. These are cancers caused by human papillomavirus (HPV) infection. They include anal, oral and cervical cancer.

Question 52

Autoimmune diseases arise from an inappropriate immune response of the body against substances and tissues normally present in the body. The immune system mistakes some part of the body as a pathogen and _______ its own cells.

Answer 52

attacks

Question 53

What is Insulin-dependent diabetes mellitus?

Answer 53

o Pancreatic beta-cell destruction, marked by the production of antibodies to the pancreatic beta-cells, occurs over many years and ultimately results in metabolic abnormalities first manifested as impaired glucose tolerance and then progressing to symptomatic hyperglycemia.

Question 54

What is Multiple sclerosis? (2)

Answer 54

o Disease of the central nervous system (CNS), with characteristic inflammatory lesions and demyelination that causes damage to the protective covering (myelin sheath) that surrounds nerve fibers in your brain, the nerves leading to the eyes (optic nerves) and spinal cord. When the myelin sheath is damaged, nerve impulses slow or even stop, causing neurological problems.
o Antibodies that recognize components of the CNS may be involved.

Question 55

What is Rheumatoid arthritis? (2)

Answer 55

o characterized by joint inflammation.
o Antibodies that recognize components found in joints and surrounding tissue.

Question 56

What is Systemic Lupus erythematosus? (2)

Answer 56

o widespread inflammation and tissue damage in the affected organs. It can affect the joints, skin, brain, lungs, kidneys, and blood vessels.
o antibodies that bind to nucleic acids (DNA or RNA), proteins and complexes of DNA or RNA with proteins.

Question 57

Summary of functions of immune cells:

Answer 57

Question 58

Summary of functions of immune cells:

Answer 58

Question 59

Summary of neutralization of extracellular bacteria:

Answer 59