cancer immunity

Question 1

what cells give a good prognosis

Answer 1

CD8+ cells, TLS and M1

Question 2

what cells give a bad prognosis

Answer 2

M2 and Treg due to a immunosuppressive role

Question 3

what is the function of the antigen processing machinery

Answer 3

that proteins of the cell are destroyed into smaller peptides and get loaded onto HLA/MHC class 1 which presents the peptides to the CD8 T cel

Question 4

oncofoetal proteins

Answer 4

proteins that are normally expressed during embryology but are now being expressed by the tumor

Question 5

neo antigen

Answer 5

somatic mutation has lead to the making of non self proteins or antigens

Question 6

cross presentation

Answer 6

dendritic cells load peptides/antigens derived from exogenous route onto HLA class 1 molecules

Question 7

what happens in the main killing pathway when a CD8+ cytotoxic T cell binds to a transformed cell

Answer 7

the t cell will start to produce perforin and granzyme B which will produce pores in the cell membrane of the bad cell and cause apoptosis

Question 8

explain FAS-FASL interaction

Answer 8

this is the non main pathway of killing a transformed cell by T cell. FAS-FASL will interact and activate caspase 8 which will active caspase cascades and this will lead to cell death

Question 9

why are anti tumor immune responses desirably dominated by TH1 type CD4 responses

Answer 9

because these will produce pro inflammaitory cytokines like IL12 and IFN-y which will promote tumor immunity.

Question 10

which signals proliferate T0 cells into Treg cells

Answer 10

TGF-B and IL-2

Question 11

in which two pathways can a tumor escape the immune system

Answer 11

PD-L1 expression in tumor

immune suppresed microenvironmend

Question 12

explain the working of PD-L1

Answer 12

PD-L1 is a ligand that binds and transmits a negative signal to T cells which causes T cells to become inhibited. the effect is loss of HLA/MHC class 1

Question 13

what normaly happens when MHC class1 is lost

Answer 13

NK cells will recognize that MHC class 1 is lost and cause lysis. however this is dependend on ligands in the tumor, these ligands can be lost and then the NK will not come into action

Question 14

what are tumours with a high mutation rate

Answer 14

polymerase mutatns (POLE) and mismatch repair deficient tumours

Question 15

which tumours often have a HLA class 1 defect

Answer 15

MMRdeficient tumours

Question 16

how does IL2 therapy work, what are downsides to this therapy

Answer 16

you will activate T cells, high toxicity and not cancer specific

Question 17

how does TIL therapy work and what are downsides to this therapy

Answer 17

tumour antigens are grown. downsides are time/costs and highly dependent on in vitro manipulation

Question 18

how do neoantigen targeted therapies work, what are downsides

Answer 18

mutation in tumor is detected and then vaccinated against. usage of gene sequencing. downsides are high costs and time

Question 19

how do antigen therapies tumor associated proteins work

Answer 19

e.g. GP100 glycoprotein enriched in melanocytes, vaccination against this specific protein. downside is limited efficacy

Question 20

how does checkpoint blockade work

Answer 20

PD-L1 is on the APC and PD-1 on the T cell. you can block PD-1 on the T cell and then you will block the negative signal and thus elimination of the cell can occur.