adaptive sensing

Question 1

What are features of adaptive immunity

Answer 1

-recognise majority of any microbial or non-microbial molecule (antigens) w/ high degree of specificity
-large receptor diversity
-adaptable; receptors created by somatic recombination of gene segments

Question 2

What is an antigen

Answer 2

A molecule recognised by adaptive immune cells

Question 3

what will an antigen bind to

Answer 3

to either a T cell receptor or antibody (B cell receptor), or both

Question 4

what is an epitope

Answer 4

precise part of antigen recognized by T or B cell receptor - antigen can have multiple epitopes

Question 5

what is a paratope

Answer 5

the part of the antibody or T cell receptor that binds to the epitope

Question 6

how do T cells recognise Ag (antigen) presented to them

Answer 6

by professional antigen presenting cells (APC) e.g macrophage

Question 7

how do B cells recognize Ag (antigen)

Answer 7

on their own

Question 8

what are 2 features of the T cell antigen receptor

Answer 8

-only membrane bound
-called: T Cell receptor (TCR)

Question 9

what are 4 features of B cell antigen receptors

Answer 9

-membrane bound and secreted
-secreted form has immune effector functions
-secreted form called antibody (Ab) or immunoglobin (Ig)
-membrane form called B cell receptor (BCR) or surface immunoglobin (slg)

Question 10

what do surface receptors allow a cell to do

Answer 10

to recognize antigens

Question 11

how many Ag binding sites does a T cell receptor and antibody have each

Answer 11

T cell receptor - 1 Ag binding site
antibody - 2 Ag binding site

Question 12

what are the two chains that a T cell receptor is composed of

Answer 12

alpha and beta chain

Question 12

how are antigen receptors created

Answer 12

somatic recombination

Question 13

what is VDJ recombinase used for

Answer 13

to recombine different gene segments

Question 14

what is the role of RSSs (recombination signal sequences)

Answer 14

used to align V, D and J segments

Question 15

what are steps to create junctional diversity

Answer 15

1)joining of V,D and J (RSSs)
2)addition of bases
3)deletion of bases
4)sequence aligns
5)fill in the gaps

Question 16

what does the somatic recombination of V, D and J genes allow the creation of

Answer 16

T cell receptors and antibodies (B Cell receptors) that can recognize almost any protein or organic molecule

Question 17

what is the process of clonal expansion

Answer 17

-T/B cell sees its Ag = becomes activated
-activated T/B cells divide
-all daughter cells have identical Ag specificity
-time to activate + expand Ag-specific T/B cells to effective number = slow adaptive response

Question 18

what are the advantages of adaptive sensing

Answer 18

-adaptable
-somatic rearrangement of gene segments allows creation of receptors that can recognize almost any antigen
-highly specific

Question 19

what are the disadvantages of adaptive sensing

Answer 19

-slow, requires time to activate and clonally expand cells w/ receptor
-high specificity = easy for microbe to evade recognition by changing antigen structure
-receptors cant distinguish pathogens from self/innocuous molecules