BOD L19 - Tumour Immunotherapy Flashcards
To understand what cancer immunotherapy is. To identify the main types and mechanisms of immunotherapy. Questions: - Can immune stimulators combat cancer? - Which forms of immunotherapy can be used? - Is vaccination effective against established tumours? - Can anti-tumour responses be generated in vitro? - Can in vitro responses translate into in vivo effects? - What barriers are there to develop effective IT?
Why is cancer immunotherapy difficult?
Cancers are ‘self’ and immune system is educated to not react against self antigen.
Briefly how does a cancer vaccine work?
Tumour cell broken up to release antigens.
In body, APCs able to recruit T cells to recognise antigens.
Then CTLs able to recognise & destroy tumour cells, and Th cells able to educate other T/B cells for AB/ADCC/cytokine attack.
How was the first cancer therapies discovered?
Cancer patients were given fungal and bacterial infections, and it was noted some tumours went into regression.
First cancer therapies were bacterial and fungal components. BCG bacterial protein first used as adjuvant.
How can immune cell phenotypes present in cancers be a prognosis predictor?
High levels of CD8+ and CD4+Th1 T cells were linked with positive prognosis.
Poor linked with Th2, Th17 and Treg.
What are the two different categories of immunotherapy?
The subcategories, with examples?
Active and passive.
Either of these can be non-specific or specific.
What are the two examples of passive immunotherapy used?
T cell therapy
Tumour-antigen specific T cells can be removed from patient and expanded in vitro. Then transfered back into patient.
Monoclonal antibody therapy
Antibodies against tumour antigen given to patient, which kill cancer cells.
What are four strategies of cancer immunotherapy?
Cancer vaccines. T cell therapy. Monoclonal antibodies. Oncolytic viruses.
What cytokine has seen good success as a therapy for cancer?
IL-2 therapy in kidney cancer.
Give an example of passive, non-specific immunotherapy
BCG
Give an example of active, specific immunotherapy
Vaccine (preventative/therapeutic)
Give an example of passive, non-specific immunotherapy
LAK (lymphokine activated killer) cells, cytokines
Give an example of a passive, specific immunotherapy
antibodies, T cell therapy.
What are the four cancer immunotherapy strategies?
Vaccines,
antibodies,
ex-vivo activated T-cells or NKs.
oncolytic viruses.
What are the four ways antibodies can kill target cells?
CDC, ADCC, direct apoptosis, conjugated to toxin
What molecule competetively binds B7 during T cell activation?
CTLA-4.
Checkpoint inhibitor in T cells, downregulate immune response.
What are two good targets for inducing immune responses to tumours?
CTLA4, blocking this causes tumour rejection.
Tumours can up-reg CTLA4 and CTLA4 expressing T cells (Tregs) to dampen the immune response.
PD-1 also blocks CTL tumour cell death. Good target to inhibit to cause CTL-mediated death
