6/04

Question 1

What’s a multivalent pathogen?

Answer 1

It’s a pathogen characterized by several epitopes that may be identified by the B cells

Question 2

What’s a monoclonal response?

Answer 2

It’s an immune response in which all the antibodies are against the same pathogen and the same epitope with the same affinity

Question 3

How can we obtain hybridoma cells for the production of mAb?

Answer 3

We have to fuse a B cell and a plasma neoplastic cell and make them grow in a HAT medium

Question 4

Why do we use the HAT medium?

Answer 4

It’s used to select hybridoma cells: it’s made of hypoxanthine, thymidine and aminopterin. The first two are used by B cells to synthetize nucleotides, the latter block the tumoral cells’ growth.

Question 5

What are the CD markers?

Answer 5

Cd are cluster of differentiations: molecules expressed on the surface of immune cells specifically recognized by clusters of mAb

Question 6

Which kinds of mAb can we produce?

Answer 6

chimeric mAb: human constant portion and murine variable portion
humanized mAb: murine hypervariable region and the rest is human
fully human
fully murine

Question 7

How can we produce mAb?

Answer 7

• phage display: for fully human or humanized
• plant production

Question 8

Which mAb we can use against tumor and why?

Answer 8

rituximab: recognize CD20 on tumoral B cells (and also on healthy) and induce the NK cell against them.

cetuximab: binf the EGF receptor on tumor cell increasing their visibility

trastuzumab: block the survival and proliferative signals of Her2

anti CTLA4 and anti PD1: inhibite the swithcing off of T cells proliferation after the infection. they’re antagonist of CD28

Question 9

Definition of a vaccine

Answer 9

biological preparation able to induce a protective immune memory against infectious diseases

Question 10

Which are the basic components of the memory response ?

Answer 10

production of antibodies by memory B cells
persistent CD8 T cells
memory helper CD4 T cells

Question 11

Which are and why are presente differences between a normal response and a memory response?

Answer 11

• no need of co stimulation
• IL7 dependent
• more efficient
• the bcr and tcr have more affinity
  these differences are driven by epigenetic modification

Question 12

Which population of memory T cells can we find?

Answer 12

central memory: in the lymphoid organs
effector memory: circulating

Question 13

What’s the threshold of memory T cells?

Answer 13

It’s the minimum number of T cells necessary to induce an immune response in case of a re-infection. If the number of memory T cells is under the treshold we have the loss of memory

Question 14

how can we keep the memory T cells active?

Answer 14

• cytokines: IL7, IL2, IL15
• repeated antigen re-stimulation: re-entry of the same pathogen
• persistent antigen re-stimulation: residual microbial depots

Question 15

Which vaccines have been used agaist polio?

Answer 15

SALK: killed virus -> MHCII
SABINE: live attenuated virus -> MHCI

Question 16

Which kind of vaccines can we find and agaist which disease are used? (list)

Answer 16

• inactivated vaccine: polio, hepatitis a
• subunit vaccine: hepatitis B, influenza
• live, attenuated vaccine: measles, rubella, varicella
• toxoid vaccines: diphteria, tetanus
• dna vaccine: zika virus, herpes zoster

Question 17

Shortly describe how every type of vaccine works

Answer 17

• inactivated vaccine: inactivated microbial toxin
• subunit vaccine: microbial sugar conjugated to proteins
• live, attenuated vaccine: pathogen without the pathogenic genes
• toxoid vaccines: exotoxin inactivated
• dna vaccine: naked dna plasmid coding for the proteins of the pathogen

Question 18

How can we do a vaccine administration and why?

Answer 18

dermal, intradermal, intramuscular, oral administration.
1- The vaccine passes through the lymphatic vessels
2- It reaches APC
3- APC arrive to the lymphoid organ and present the antigen to T cells
4- Also the vaccine itself, though the lymphatic vessels, reaches the lymphoid organs so also the B cells can recognize the antigen

Question 19

what’s an adjuvant?

Answer 19

is a substance that enhance the immunogenicity of antigens causing a slow release, aggregating them and triggering danger signals and pro-inflammatory cytokines

Question 20

What’s a multivalent vaccine? Examples?

Answer 20

A multivalent vaccine contain different antigens together. An example is the DTP: diphteria, tetanus and pertosse

Question 21

What’s a conjugated vaccine? Examples?

Answer 21

Conjugated vaccines contain other substances other than the antigen (they need a protein carrier). For example, the meningococcus vaccines: this vaccine is made mostly by sugars present on the bacteria wall so it must be conjugated with proteins.

Question 22

Definition of tolerance

Answer 22

non-response to a self or non-self antigen which should induce an immune response

Question 23

What’s the central tolerance?

Answer 23

Is the ability of the immune system to learn which antigen should be destroyed and which should be tolerated. This happens thanks to the negative selection of self-reactive B and T cells