Lecture 3

Question 1

All antibodies start as

Answer 1

IgM

Question 2

IgM initially has a constant region encoded by

Answer 2

Cu genes

Question 3

What is the “effector function” of a antibody?

give some examples

Answer 3

what happens after it is bound to the antigen

I.e

compliment activation
placental transfer
sensitising mast cells

Question 4

Secreted IgM is _____ which helps increase avidity

Answer 4

pentameric

Question 5

Only IgA antibody are found on ______ surfaces

Answer 5

mucosal

(protection against things you eat

Question 6

Isotypes have the same ______ region

Answer 6

variable

Question 7

Only____ chains undergo class switch recombination (CSR)

Answer 7

heavy

Question 8

____ will cut the DNA and moves the VDJ region upstream, bypassing the unwanted heavy chain genes to make different ______

Answer 8

AID will cut the DNA and moves the VDJ region upstream, bypassing the unwanted heavy chain genes to make different Isotypes

Question 9

AID recognises a target sequence in DNA, finds _______ in that sequence and removes (deaminates) it and converts it to Uracil.

Answer 9

AID recognises a target sequence in DNA, finds cytosines in that sequence and removes (deaminatese) it and converts it to Uracil.

Uracil is then removed from DNA as per normal DNA repair mechanisms

Question 10

Uracil is then removed from DNA as per normal DNA repair mechanisms. This can cause __ ___ ___ if the cleavages are close enough together

Answer 10

double-stranded breaks

(If two such breaks occur, one on either strand a staggered double-strand break can be formed (DSB). It is thought that the formation of these DSBs in either the switch regions or the Ig variable region can lead to CSR or GC, respectively.)

Question 11

This whole system is targeted and specific by signalling from…

Answer 11

T cells

Question 12

An activated dentifrice (APC) will present to t cells.

The T cell will then produce…

Answer 12

IL4, IL5, IL13 etc

interleukins

Question 13

The IL’s, will then signal to B cells to under go ____ ___________, with the hope of changing the isotype of the antibodies

Answer 13

CSR differentiation

Question 14

Mutations are introduced into GC B cell Ig V genes at “random” = somatic

what is meant by this?

Answer 14

Alterations in DNA that occur after conception. Somatic mutations can occur in any of the cells of the body except the germ cells (sperm and egg) and therefore are not passed on to children.

Question 15

match the T(helper) cell receptor to its B cell counter part

(which together induct CSR and SHM in germinal centres)

CD40L
TCR
ICOS

Answer 15

CD40L - CD40
TCR - MHCII
ICOS - ICOSL

Question 16

AID initiates __ ___ ____ and somatic mutation

What are some immune deficiencies realted to this pathway

Answer 16

Class switch recombination

Question 17

CVID - common variable immune deficiency is the most ______

Answer 17

Common

Question 18

Live attenuated virus are?

Answer 18

a non-pathogenic sample of viruses

Question 19

HIV targets ____ _ cells

Answer 19

cd40+ t cells

Question 20

Recombinant proteins (virus-like antigens) provide opportunities to tailor Vaccine responses because:

Answer 20

Individual antigens can be chosen

Antigens can be modified hrough pritein engineering to change their properties in favourble ways

Antigens can be made as soluble subunit vaccines, as VLPs (virus-like particles)

Question 21

The GP120 and gp41 antigens have been used as the basis for…

Answer 21

HIV vaccine trials

none of the big 3 trials have worked

Question 22

With HIV: A very large number of _____ _____ circulate at the same time

Answer 22

genetic variants

Question 23

Mutations introduced during viral replication change _______ _________ on the virus: rendering existing immune responses irrelevant.

Answer 23

Mutations introduced during viral replication change immune determinants on the virus: rendering existing immune responses irrelevant.

Question 24

Another way that HIV avoids immune responses is by shedding gp120 to expose ___ ____ ______

Answer 24

irrelevant antibody epitopes

Immune responses do not occue to all antigens eually, some dominate at the expense of others

Question 25

Increasing the number of irrelevant targets////

Answer 25

increases the likelihood of irrelevant antibodies dominating the response

Question 26

HIV also shields itself with

Answer 26

Carbohydrates

Each gp120 molecule carries between 20 and 30 N-linked glycans

Question 27

HIV protection measure 4: The highly conserved co-receptor binding site on _____ is only exposed after binding to _____ , thus this site is not accessible for neutralising antibodies

Answer 27

HIV protection measure 4: The highly conserved co-receptor binding site on gp120 is only exposed after binding to CD4, thus this site is not accessible for neutralising antibodies

Question 28

The immune system in some individuals can generate _______ antibodies that work ________multiple of HIV isolates

Answer 28

The immune system in some individuals can generate neutraliing antibodies that work against multiple of HIV isolates