Immunology

Question 1

What are the functions of the complement pathway?

Answer 1

• Lyse microbes directly (formation of Membrane Attack Complex)
• Increase chemotaxis
• Opsonisation

Question 2

What are the three complement pathways?

Answer 2

• Classical pathway
• Alternative pathway )
• Lectin pathway

Question 3

Give some examples of pattern recognition receptors

What is the function of PRRs?

Answer 3

• Secreted and circulating, e.g. lectins, collectins
• Cell-associated, e.g. toll-like receptors, nod-like receptors

Function:
- PRRs recognise PAMPs (pathogen associated molecular patterns) and DAMPs (damage associated molecular patterns)

Question 4

Give some examples of antigen presenting cells

Answer 4

B cells
Dendritic cells
Macrophages

Question 5

What is the function of Major Histocompatibility Complex (MHC)?
How is MHC subdivided?

Answer 5

• Proteins that mark self as self

- Subdivided into class I (all nucleated cells) and class II (antigen presenting cells)

Question 6

What types of hypersensitivity reaction are there?

Answer 6

Type 1, 2, 3 and 4

Question 7

What is the mechanism of Type 1 hypersensitivity reaction? Give an example

Answer 7

• Production of IgE antibodies

- Anaphylaxis

Question 8

What is the mechanism of Type 2 hypersensitivity reaction? Give examples

Answer 8

• Antibody-antigen binding –> phagocytosis

- Goodpasture’s syndrome, haemolytic anaemia

Question 9

What is the mechanism of Type 3 hypersensitivity reaction? Give an example

Answer 9

• Antibody-antigen binding –> deposition of immune complexes
• SLE

Question 10

What is the mechanism of Type 4 hypersensitivity reaction? Give an examples

Answer 10

• Activation of T lymphocytes

- Contact dermatitis, rheumatoid arthritis, IBD

Question 11

Compare the characteristics of innate and adaptive immunity

Answer 11

SICH

Innate:

• SPECIFICITY: limited
• IMMUNOLOGICAL MEMORY: absent
• CELLULAR COMPONENTS: neutrophils, macrophages, NK cells
• HUMORAL COMPONENTS: complement

Adaptive:

• SPECIFICITY: highly specific
• IMMUNOLOGICAL MEMORY: present
• CELLULAR COMPONENTS: T cells, B cells
• HUMORAL COMPONENTS: antibodies

Question 12

What are the components of the innate immune system?

Answer 12

• Physical/chemical barriers, e.g. lysozymes in tears, skin, mucociliary escalator in bronchi
• Cellular components, e.g. macrophages, neutrophils, NK cells
• Humoral components, e.g. complement pathway

Question 13

What are the five classes of antibodies?

What are they associated with?

Answer 13

IgA - in colostrum
IgG - passive immunity to fetus (crosses placenta)
IgM - first response to antigen
IgD - associated with B cell activation
IgE - Type 1 hypersensitivity reactions, e.g. anaphylaxis