Immunology 2

Question 1

What are the main characteristics of the Adaptive system ?

Answer 1

• Antigen specificity
• Diversity
• Immunologic memory (ability to respond to a 2nd encounter of the same antigen more rapidly than the 1st encounter)
• Ability to distinguish b/wn self and non-self recognition

Question 2

What are the 2 major cell groups of Adaptive Immunity ?

Answer 2

1) B lymphocytes (B cells)

2) T lymphocytes (T cells)

Question 3

Name 3 types of Antigen-presenting cells (APC’s) ?

What are APC’s described as and what is their role?

Answer 3

• Dendritic cells
• Macrophages
• B lymphocytes

A cross-bridge b/wn Innate and Adaptive immunity. APC’s internalize antigens, break them down (and display part of the antigen bound to MHC II)

Question 4

MHC II is only expressed by APC’s and interacts with T cells. TRUE or FALSE ?

Answer 4

TRUE

Question 5

B lymphocytes mature in the red bone marrow. TRUE or FALSE ?

Answer 5

TRUE

Question 6

B lymphocytes binds to B cell receptors. TRUE or FALSE ?

Answer 6

TRUE

Question 7

B cell receptors are membrane bound antibodies. TRUE or FALSE ?

Answer 7

TRUE

Question 8

Name the 2 co-stimulatory molecules that T cells express on their membrane ?

Answer 8

1) T helper (Th) CD4+

2) T cytotoxic (Tc) CD8+

Question 9

What do T cells recognise ?

Answer 9

Antigens that are bound to MHC

Question 10

What are the two types of responses in adaptive immunity ?

Answer 10

1) Humoral response (B cells differentiate to Plasma cells which produce Antibodies) …Antibodies go on to bind to antigen etc
2) Cellular response (concerned with T cells)

Question 11

Describe the structure of a Surface and soluble antibody ?

Answer 11

Both consist of Heavy and light chains joined together by DISULFIDE BONDS w/antigen binding sites on their surface

Question 12

Does the light or heavy chain determine the class of the antibody ?

Answer 12

Heavy chain

Question 13

What happens when Th cells are activated ?

Answer 13

Cytokine secretion occurs -which then leads to activation of B, Tc cells and macrophages

Question 14

Name the 5 major classes of antibodies/Immunoglobulins ?

Answer 14

1) IgA (alpha)
2) IgD (delta)
3) IgE (epsilon)
4) IgG (gamma)
5) IgM (mu)

Question 15

What is meant by ‘Dimer of dimers’ ?

Answer 15

This is when 2 heavy-light chains of antibodies are joined together

Question 16

What region of an antibody is the most difference found ?

Answer 16

CD region (complementary determining region)/Antigen binding site

Question 17

What does the c-region of antibodies result in ?

Answer 17

The 5 different isotopes;

Alpha, Gamma, Epsilon, Mu and Delta

Question 18

Name 3 regions of an Antibody ?

Answer 18

1) V (variable) region - consists of 110 amino acids
2) C region - involved in the structure of the antibody - determines the effector activity
3) CD region - (complementary determining region)/Antigen binding site

Question 19

What fragments are produced when Antibodies are digested by the enzyme, Pepsin ?

Answer 19

1) Fab fragments (Antigen binding site)

2) Fc fragments (binds to B cells and only contains H chain)

Question 20

What is the role of Mercaptoethanol?

Answer 20

Reduces the disulfide bonds therefore producing two fragments

Question 21

How many sub-classes of IgG are there, name them

Answer 21

4 sub-classes; IgG 1, IgG 2, IgG 3 and IgG 4

Question 22

Which is the most potent IgG subclass ?

Answer 22

IgG 3

Question 23

Which IgG subclasses are able to cross the placenta ?

Answer 23

IgG 1, IgG 3 and IgG 4

Question 24

Where is IgA predominantly found ?

Answer 24

In secretions. e.g: Milk, Saliva, Tears and Mucus

Question 25

What is the role of IgA ?

Answer 25

To prevent the attachment of bacteria and viruses to the mucous membrane. Also protects from newborns

Question 26

Name 3 theories for antibody diversity ?

Answer 26

1) Germ-line theory -(Germ cells containing large numbers of Ig genes)
2) Somatic-variation theory (Genome = contains small amount of Ig genes therefore antibody specificity came about by mutation or recombination)
3) One gene -one polypeptide theory (generally accepted)

Question 27

In L chains, the V region is coded for by which 2 genes ?

Answer 27

V and J (different V an J genes fuse together)

Question 28

In H chains, the V region is coded for by which 3 genes ?

Answer 28

V, J and D

Question 29

What are Viruses ?

Answer 29

Small nucleic acids with protein and lipoprotein coating

Question 30

What is the difference between Protozoans and Helmintic Parasites ?

Answer 30

• Protozoans are unicellular parasites that reside and multiply in host cells.
• Helmintic Parasites = multicellular - eventhough they infect humans are able to survive on their own

Question 31

What parasite causes Malaria ?

Answer 31

P. Falciparum (P = plasmodium)

Question 32

What are the 3 classes of reactions involved in Bacterial cell metabolism ?

Answer 32

• Class 1 reactions
• Class 2 reactions
• Class 3 reactions

Question 33

What occurs in Class 1 reactions ?

Answer 33

Glucose and Phosphate combines with other small molecules and form PRECURSOR MOLECULES and ATP

Question 34

What occurs in Class 2 reactions ?

Answer 34

Precursor molecules create larger structures e.g: Nucleotides, AA’s and Hexosamines

Question 35

What occurs in Class 3 reactions ?

Answer 35

Class 2 structures create; Peptidoglycan, Proteins and RNA & DNA

Question 36

Class 3 reactions are the best target for bacterial chemotherapy. TRUE or FALSE ?

Answer 36

TRUE

Question 37

What are the 2 types of resistance specific to bacteria ?

Answer 37

1) Acquired - emerge from previously sensitive bacterial populations
2) Intrinsic - Prevents antibiotic action

Question 38

Name the 3 methods of Horizontal Gene Transfer ?

Answer 38

1) Bacterial transformation (releases DNA to recipient cell)
2) Bacterial transduction (releases Phage)
3) Bacterial conjugation (transfers plasmid from donor to recipient cell at the site they join together)

Question 39

What is Vancomycin ?

Answer 39

An antibiotic used as a last resort e.g to treat MRSA