TOPIC 4 - MICROBIOLOGY AND IMMUNOLOGY

Question 1

Cytokines

Answer 1

a protein secreted by cells that interacts with and affects the behaviour of a nearby cell bearing the appropriate receptors. Affect multiple functions (regulate innate immunity, adaptive immunity, hematopoiesis and more). Other names include interleukins, interferons, CSFs, TNFs

Question 2

Interferon response

Answer 2

stimulates inhibition of viral replication

Question 3

apoptosis

Answer 3

cellular suicide characterised by DNA fragmentation

Question 4

extravasation

Answer 4

migration of neutrophils into inflamed tissues

Question 5

respiratory burst

Answer 5

temporary rise in oxygen consumption and toxic oxygen species production

Question 6

acute-phase response

Answer 6

a notable rise or reduction of plasma proteins in response to IL-6

Question 7

What are the five classes (isotypes) of immunoglobulins

Answer 7

IgA, IgD, IgE, IgG, IgM

Question 8

MHC Class I

Answer 8

HLA-A, HLA-B, HLA-C, expressed on all nucleated cells

Question 9

MHC Class II

Answer 9

HLA-DR, HLA-DP, HLA-DQ, expressed on antigen presenting cells (dendritic cells, macrophages and B cells)

Question 10

Macrophage

Answer 10

Phagocytosis and activation of bactericidal mechanisms. Antigen presentation

Question 11

Eosinophil

Answer 11

Killing of antibody-coated parasites

Question 12

Dendritic cell

Answer 12

Antigen uptake in peripheral sites. Antigen presentation

Question 13

Basophil

Answer 13

Promotion of allergic responses and augmentation of anti-parasitic immunity

Question 14

Neutrophil

Answer 14

Phagocytosis and activation of bactericidal mechanisms

Question 15

Mast cell

Answer 15

release of granules containing histamine and active agents

Question 16

C-reactive protein

Answer 16

Binds capsule of several bacteria, aids phagocytosis, triggers the complement cascade

Question 17

Mannose binding lectin

Answer 17

binds mannose residues on pathogens, triggers the complement cascade

Question 18

Complement proteins

Answer 18

Pro-enzymes (C1, C2 etc) which are triggered after binding a pathogen to produce a cascade of reactions which generate effector molecules against the pathogen

Question 19

Chemokine

Answer 19

A secreted protein that attracts cells bearing the appropriate receptors. Two groups of receptors, both of which contain two cysteine molecules (CCR, CXCR)

Question 20

Phagocytes

Answer 20

Polymorphonuclear neutrophils - the most numerous but short-lived cells that are found in circulation therefore need to be attracted to tissues.
Mononuclear phagocytes (macrophages, monocytes) - long-lived cells, found in circulation and tissues
Function: enter an infected site from the circulation where they bind, engulf and kill a wide variety of microbial agents. Produce immunomodulatory substances e.g. cytokines, chemokines, which regulate the immune response. Act as a first line defence against infection

Question 21

Cytotoxic cells

Answer 21

target infected or altered cells, and release granules whose contents are toxic. They include natural killer cells, eosinophils, and macrophages

Question 22

Basophils and mast cells

Answer 22

release granules containing inflammatory mediators to augment the action of immune cells, but this can increase inflammation and mediate unwanted (hypersensitivity) reactions e.g. allergies