Immunology

Question 1

what is the difference between MHC 1 and MHC 2?

Answer 1

MHC 1 expressed on all cells - presents to cytotoxic CD* T cells, triggering apoptosis. normally in case of intracellular organisms ie virus, parasites
MHC 2 expressed on APC cells (especially dendritic cells) - present to helper T cells, priming them for further action

Question 2

which type of cell is the most common antigen presenting cell (APC)?

Answer 2

dendritic cell

Question 3

what are primary vs secondary lymphoid organs?

Answer 3

primary - where immune cells deveop/mature (ie thymus, bone marrow)
secondary - where immune cells interact with antigens (ie lymph nodes, spleen)

Question 4

what are the main subtypes of T helper cells, and which cytokines do they secrete?

Answer 4

Th1 - Interferon gamma, IL2
Th2 - secretes IL4, IL5, IL13
Th17 - IL17A, IL17F, IL22

Question 5

which T helper cell subtype is associated with allergic and parasitic infections?

Answer 5

T helper 2

Question 6

which T helper cell is most likely to be involved in viral infections?

Answer 6

TH1

Question 7

which T helper cell is most likely to be involved in bacterial and fungal infections?

Answer 7

TH17

Question 8

how do T helper cells coordinate an immune response against an infection?

Answer 8

through cytokine release

Question 9

which type of T helper cell secretes interferon gamma?

Answer 9

TH1

Question 10

what is the role of cytokines?

Answer 10

• communicate locally/at a distance
• recruit more cells
• coordinate immune cell activity

Question 11

what are the enzymes used by cytotoxic T cells and NK cells to kill infected cells?

Answer 11

perforin

granzyme

Question 12

what cytokine do NK cells secrete?

Answer 12

interferon gamma

Question 13

what do NK cells do?

Answer 13

help kill infected cells if T cell response is not optimal

Question 14

which type of immunoglobulin does breast milk contain?

Answer 14

IgA

Question 15

what are the physiological changes that occur on the target cell membrane as a result of opsonisation?

Answer 15

• negative charge removed so phagocytes can bind

- increase in number of receptors for phagocytes to bind to

Question 16

what is the aetiology of primary immunodeficiency diseases?

Answer 16

genetic abnormalities (mutations)

Question 17

how can primary immunodeficiency diseases be classified?

Answer 17

• abnormalities in innate immune system
• abnormalities in lymphocyte development
• abnormalities in lymphocyte reaction to antigens

Question 18

what is the main primary immunodeficiency disease that results from abnormalities in lymphocyte development?

Answer 18

severe combined immunodeficiency (SCID)

Question 19

what types of immunodeficiency disorders are hypogammaglobulinaemia and agammaglobulinaemia?

Answer 19

primary immunodeficiencies, resulting from abnormal immune reaction to antigens

Question 20

what is seen is common variable immunodeficiency (CVID)?

Answer 20

low levels of IgG

Question 21

what are the three mechanisms by which genetic changes can cause primary immunodeficiency disease?

Answer 21

• single nucleotide polymorphisms
• mutations
• polygenic causes

Question 22

how is primary immunodeficiency treated?

Answer 22

mild cases - antibiotic prophylaxis

severe cases - immunoglobulin replacement therapy

Question 23

what is the treatment for Severe Combined Immunodeficiency (SCID)?

Answer 23

• stem cell transplant early in life

- gene therapy if no suitable stem cell donor

Question 24

what is the pathology behind SCID?

Answer 24

lymphocyte precursors are mutated so don’t respond to growth factors promoting differentiation

Question 25

what’s the acronym that characterises infections seen in immunocompromised patients?

Answer 25

SPUR:

serious, persistent, unusual, recurrent

Question 26

what is the common presentation of immunodeficiency caused by abnormalities in antibodies and T cells respectively?

Answer 26

• antibody abnormality: recurrent respiratory infections

- T cell abnormality: serious viral, fungal and intracellular infections