Adaptive Immunity L8

Question 1

what happens in the complement system

Answer 1

complement binding to the surface, “tagging” pathogen so it can be recognised more easily by other parts of the immune system
Three different pathwaysall lead to C3b on microbe
C3b tagging microbe – saying its infectious ,immune system gets information to know that it is infectious
Three different options after

Question 2

what do B cells make

Answer 2

antibodies (immunoglobulins)
Cell surface (B cell receptor) or secreted
Protection against extracellular pathogens & toxins

Question 3

what do T cells make

Answer 3

T cell receptors
Cytotoxic (killer T cells)
T helper cells

Question 4

what is part of the innate immune system

Answer 4

PAMPS by means of PRRs

Question 5

what is part of the adaptive immune system

Answer 5

Diverse molecules, including PAMPS, but
is adaptable to recognise new molecules
Has very specific recognition:
by specific antibodies and T cell receptors

Question 6

what is PAMP

Answer 6

pathogen associated molecular pattern

Question 7

what is PRR

Answer 7

pattern recognition receptor

Question 8

what do PRRs do

Answer 8

maximally recognise hundreds of different PAMPS

the adaptive immune system is almost infinitely variable in its capabilities for specific recognition

Question 9

what is an antigen

Answer 9

from antibody generator

Question 10

what do antibodies bind to

Answer 10

Many antibodies may bind the same antigen, each a separate site termed an antigenic determinant or epitope
An antigen can also show repeated epitopes
Antigens can be diverse molecular structures

Question 11

how are T and B cells similar

Answer 11

both have variable region where the antibody can vary massively
Both have constant region
Both embedded in the membrane – transmembrane region

Question 12

how are antigens recognised by different antibodies

Answer 12

Antibodies recognise specific structures (epitopes) on the antigen in its original (native) shape
recognise different sections

Question 13

what happens during antibody recognising antigen

Answer 13

epitopes recognised by Tcell receptors often buried
antigen must first be broken into peptide fragments
epitope peptide binds to self molecule, an MHC molecule
Tcell receptor binds to complex of MHC and epitope peptide

Question 14

what are the two main types of MHC

Answer 14

class 1 and class 2

Question 15

where are B and T cells from

Answer 15

lymphoid progenitor cells

Question 16

where do B cells develop

Answer 16

bone marrow

Question 17

where do T cells develop

Answer 17

thymus

Question 18

what is somatic recombination, what does it cause

Answer 18

During development, rearrangement of the gene segments encoding the relevant genes occurs
gives each new cell a unique receptor combination

Question 19

what does clonal selection cause

Answer 19

a specific response to an infection is based on a second mechanism

Question 20

how doe individual B and T cells differ

Answer 20

Each individual B cell or T cell has a single receptor specificity

Question 21

where can antibodies bind

Answer 21

can be bound to the surface of the B cell (B cell receptor) or they can be soluble

Question 22

what is the variable region involved in

Answer 22

antigen binding

Question 23

what is the constant region involved in

Answer 23

far less variable, involved in interaction with effector molecules and cells (see back to complement)

Question 24

what is Fab

Answer 24

fragment antigen binding

Question 25

what is Fc

Answer 25

fragment crystallisable

Question 26

what are the five different antibody classes

Answer 26

IgG
IgM
IgD
IgA
IgE

Question 27

how do antibodies differ

Answer 27

• Heavy chain length
• Hinge region
• Number of carbohydrates
• Disulphide bond position

Question 28

what affects which class the antibodies are in

Answer 28

C region

Question 29

which antibody is the most abundant in serum

Answer 29

IgG

Question 30

what can IgM form

Answer 30

pentamers can bend and staple down to a surface and help activate the complement surface

Question 31

what can IgA form

Answer 31

dimers

Question 32

An example of how B cells stimulation to release antibodies

Answer 32

resting B cell encounter with antigen

stimulated B cell gives rise to antibody-secreting plasma cells

Question 33

what are T cell receptors similar to

Answer 33

Similar to antibody Fab section

Question 34

what are T cells made of

Answer 34

two chains
- α chain
- β chain
Variable and constant regions

Question 35

where do antigens bind in T cell receptors

Answer 35

variable region, allows for specificity

Question 36

where are antigens presented in T cells

Answer 36

Antigens have to be presented as peptides in MHC receptors

Question 37

what is MHC

Answer 37

Major Histocompatability Complex

Question 38

which cells have MHC 1 on their surface

Answer 38

All nucleated cells express MHC I on their surface so T cells can recognise it

Question 39

which cells have MHC 2 on their surface

Answer 39

Only antigen presenting cells have MHC class II help to activate that part of the immune system

Question 40

what happens in MHC antigen presentation

Answer 40

Virus taken into cell
Virus proteins synthesised in cytosol
Peptides then presented by MHC 1 on cell surface
Can happen on any nucleated cell
Cytotoxic T cell kills infected cells
Enzymes released by cytotoxic T cell break down genomic DNA of cell and virus cleave target proteins

Question 41

how does cytotoxic T cell kill infected cell

Answer 41

cytotoxic T cell recognises complex of viral peptide with MHC 1
CD8 on bind to MHC 1
All T c to bind and kill cell
Don’t want this all the time so have different types of T cells

Question 42

T helper functions

Answer 42

Th1 cell recognises complex of bacterial peptide with MHC 2 and activates macrophages
T follicular helper cell recognises complex of antigenic peptide with MHC 2 and activates B cell