Adaptive immunity- extracellular

Question 1

which cell act was a bridge between the immune and adaptive immune system

Answer 1

antigen presenting cells

Question 2

if naive T cells and pathogen meet

Answer 2

no response

Question 3

only way T cells can be activated is by

Answer 3

antigen presenting elsl

Question 4

APCS

Answer 4

phagocytose and process the microbe and present it to the Naïve T cell so they can recognise pathogen/tumour cell

Question 5

naive T cell

Answer 5

T cell that have no previously encountered the antigen

Question 6

effector T cell

Answer 6

T cells that have previously encountered the antigen are capable of performing the effector functions during an immune response

Question 7

Antigen presenting cells role

Answer 7

• Sense the pathogen
• Capture pathogen
• Process pathogen
• Present the pathogen to T cells

Question 8

name 4 APC

Answer 8

dendritic cells
langerhans
macrophages
B cells

Question 9

dendritic cells and langerhans (dendritic cell specialised for the skin) present the pathogen to ……………. and have what function

Answer 9

present to naive T cells

Function: T cell response against most pathogens

Question 10

macrophages and B cells present the pathogen to …………….

Answer 10

present to effector T cells

Question 11

function of macrophages

Answer 11

phagocytic activities

Question 12

function ofB cells

Answer 12

antibody response (humeral)

Question 13

APC are found in strategic locations

Answer 13

• Mucosal membrane (gut, lung)
  o Mucosal associated lymphoid tissue (MALT)
• Skin (Langerhans cells)
  o Skin associated lymphoid tissue)
• Blood (plasmacytoid cells)
• Lymph nodes (follicular dendritic cells)
• Spleen

Question 14

pathogen capture method of APC

Answer 14

• Phagocytosis (whole microbe)

- Micropinocytosis (soluble particles)

Question 15

2 types of microbes

Answer 15

• Extracellular
  o Fungal
  o protozoa
  o Most bacteria
• Intracellular
  o Virus
  o TB
  o Cancer

Question 16

PRRS recongise

Answer 16

intracellular and extracellular pathogens PAMPs

Question 17

TLR recognise extracellular pathogens

Answer 17

TLR1,2,6,4,5,11

- TLR4- Neisseria meningitidis- sepsis

Question 18

TLR recognise intracellular pathogens

Answer 18

TLR3,7,8,9

Question 19

how do APC activate the adaptive immune system

Answer 19

1. Macrophages and APC recognise pathogen
2. APC use lymphatics to get to lymphoid tissue
3. APC presents to T cells

Question 20

Major histocompatibility complexes (MHC) molecules are a type of

Answer 20

human leukocyte antigen

Question 21

HLA

Answer 21

human body version of MHC

- how pathogens are presented to naive T cells

Question 22

MHC I

Answer 22

• Expressed on all nucleated cells
• CD8 cytotoxic T cells
• Kill intracellular pathogens
  • Virus’
  • TB
  • Cancers

Question 23

MHC II

Answer 23

• Expressed on APCs, dendritic cells, macrophages and B cells
• CD4 T helper cells
  • Fungal
  • Bacteria
  • Parasitic

Question 24

key features of MHC molecules

Answer 24

• Co-dominant expression
  o Both MHC class I and II parental molecules are co-expressed in each individuals (6 of each class)
• Polymorphic genes (diff alleles)
  o Different individuals present and respond to different microbes

Question 25

Antigen presenting cells present intracellular microbes via MHC class I molecules

Answer 25

HLA-A, B and C

Question 26

Extracellular microbes presented by MHC class II molecules

Answer 26

HLA-DP, HLA- DQ, HLA-DR

Question 27

processing of intracellular microbes (MHC I)

Answer 27

1. Viral proteins present in the cytosol
2. Marked for destruction by proteasome
3. Proteasomes-generated viral peptides transported to ER by TAP proteins
4. Formation of viral peptide- MHC class I complex if right match (coded in genome)
5. APCS and non-APC present peptides from intracellular pathogens to CD8+ T cells
6. T cells only react when sensing a foreign peptide
7. Also present self peptides in this way

Question 28

Processing of extracellular microbes
Exogenous pathway (MHC II)

Answer 28

1. Microbes captured by phagocytosis or micropinocytosis
2. Degradation in small peptides in the endosome
3. Peptide rich vesicles fuse with vesicles containing MHC class II molecules
4. Formation of peptide MHC class II complex if right match
5. APCs present peptides extracellular pathogens to CD4+ T cells

Question 29

MHC I found on

Answer 29

all cell types

Question 30

MHC II found on

Answer 30

APCs- dendritic, B cells and macrophages

Question 31

peptide bonding cleft on the MHC molecules

Answer 31

highly variable region with highly polymorphic residues (coded for in the genome)

Question 32

MHC I occurs as an α chain composed of three domains

Answer 32

—α1, α2, and α3.

Question 33

MHC class II is formed of

Answer 33

two chains, α and β, each having two domains—α1 and α2 and β1 and β2—each chain having a transmembrane domain, α2 and β2, respectively, anchoring the MHC class II molecule to the cell membrane.

Question 34

no individual has the same set of

Answer 34

mHC moleculen

Question 35

Individuals have different susceptibilities rot infection

Answer 35

o Strong vs weak immune response against infectious microbes
 Pregnant
 Immunosuppressed
 Children

Question 36

HLA molecule mismatch between donor and recipient (allograft) is

Answer 36

a major cause for organ transplant rejection

GRAFT VERSUS HOST REACTION (GVH)

Question 37

HLA association with autoimmune disease

Answer 37

• Ankylosingspondylitis
  o HLA-B27 -> 90% of patients
• Insulin-Dependent Diabetes Mellitus
  o HLADQ2 -> 50-75% of patients