L1&2: Innate & Adaptive Immunity

Question 1

list examples of cell migration

Answer 1

1. to sites of infection/inflammation
2. from blood to lymph and vice versa
3. from primary lymphoid organs to secondary lymphoid organs
4. between secondary lymphoid organs

Question 2

what is chemotaxis?

Answer 2

directional migration of cells up a concentration gradient of chemotactic molecules

Question 3

What is IL-8 an example of?

Answer 3

a chemo/cytokine produced by macrophages which attracts neutrophils to the site of infection

Question 4

what are chemokines?

Answer 4

chemoattractant cytokines which play a vital role in how immune cells migrate between immune organs and to sites of infection and inflammation

Question 5

how many chemokines and how many receptors

Answer 5

47 chemokines and 19 chemokine receptors

Question 6

what is the difference between alpha and beta chemokines?

Answer 6

the position of 2 cysteines in the protein

Question 7

where do the cells that express CCR7 migrate to? and in response to which ligands?

Answer 7

cells expressing CCR7 will migrate to the lymph nodes in response to secretion of CCL19 and CCL21

Question 8

What are the 3 main components of the inflammatory response?

Answer 8

1. blood supply increases to the area affected.
2. capillary permeability increases (allows exudation of serum proteins in surrounding tissue like Abs, complement)
3. leukocyte migration

Question 9

describe the sequence of events of leukocyte migration to the site of infection (hint: phased appearance)

Answer 9

1. Neutrophils appear first (IL-8 produced by macrophages attracts them), they peak after 1-2 days, 10 fold increase in their production in the bone marrow, one way migration
2. APCs (like macrophages, DCs) are there from the start, numbers increase, migrate to LNs to present antigens
3. CTLs and Th cells arrive days later after their activation by APCs in the LNs & spleen
4. B lymphocytes arrive days later, small no. as the antibodies do their work

Question 10

can the innate system identify bacteria or viruses?

Answer 10

yes, but not very specifically, can recognize LPS

Question 11

what is the component of the pathogen the immune system sees?

Answer 11

antigen

Question 12

how much antibody does a health 70-80kg adult produce daily?

Answer 12

2-3g Ab (2/3 of which is IgA)

Question 13

primary function of antbodies?

Answer 13

bind to its antigen

Question 14

direct effector function of Ab?

Answer 14

neutralise bacterial toxins, neutralise viruses

Question 15

secondary function of Ab?

Answer 15

activation of complement, lysis of bacteria and some viruses, opsonisation of pathogen

Question 16

what is opsonization?

Answer 16

covering the pathogen with antibody to tag it for phagocytosis by macrophages/neutrophils, which have Fc receptors

Question 17

name general barriers or immune defences

Answer 17

skin, fatty acids, lysozyme, acid, commensal bacteria

Question 18

innate immunity response to Gram negative bacteria

Answer 18

Gram -ve bacteria are susceptible to lysis by complement

Question 19

innate immunity response to Gram +ve bacteria

Answer 19

they have a cell wall of peptidoglycan which makes them sensitive to degradation to lysozyme

Question 20

what do PRRs recognise?

Answer 20

PAMPs (pathogen associated molecular patterns)

Question 21

what happens in the proteasome?

Answer 21

proteins in the cell are degraded into short peptides and loaded onto MHC molecules, shipped out through the ER/Golgi to be presented to the outside world on the surface of the cell

Question 22

what must peptides be bound to and on where in order to be recognized by T cells

Answer 22

must be bound to MHC on either APCs or infected cells

Question 23

what do NK cells recognise?

Answer 23

the absence of MHC on the cell surface

Question 24

what do cytotoxic T cells recognise?

Answer 24

non-host peptides loaded onto MHC

Question 25

what do macrophages and other phagocytes do with the virus-infected cell they have ingested?

Answer 25

they degrade the proteins in the proteasome, load them onto MHC through the ER/Golgi apparatus and present these foreign peptides to the T cells

Question 26

what gene fusions produce the TCR

Answer 26

V, D, J, and C genes fusions

Question 27

each T cell has a unique _ which recognizes a certain _

Answer 27

each T cell has a unique TCR which recognizes a certain antigen

Question 28

what cells are MHC class I expressed on?

Answer 28

all nucleated cells

Question 29

what cells are MHC class II proteins expressed mainly?

Answer 29

mainly on antigen presenting cells

Question 30

besides foreign proteins like viral ones, what other cells’ peptides can be displayed on MHC class I

Answer 30

tumour peptides from tumour cells

Question 31

where are proteins degraded for presentation on MHC class II?

Answer 31

In endolysosomes

Question 32

perforin is produced by the _ of / and is a _ _.

Answer 32

perforin is produced by the degranulation of CTL/NK cells and is a granule protein

Question 33

what receptors do phagocytes have which facilitate phagocytosis?

Answer 33

phosphatidylserine residue receptors which bind the exposed phosphatidylserine residues on their surface

Question 34

where in phagocytes are apoptotic bodies destroyed?

Answer 34

in the phagolysosomes