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Flashcards in Tumor immunology Deck (17):

What is cancer immunoserveillance

The immune system recognises and destroys nascent transformed cells


What is cancer immunoediting?

As tumours are genetically unstable, the immune system can kill and also induce changes in the tumour resulting in tumour escape and recurrence


What are tumour specific antigens

Antigens found only on tumours as a result of point mutations or gene rearrangement. Derive from viral antigens


What are tumour associated antigens

Found on both normal and tumour cells, but are overexpressed by cancerous cells. Tend to be developmental antigens that become derepressed. The differentiation of antigens is tissue specific and could result from an altered modification of a protein


What evidence is there for tumour immunology

Infiltration of tumours by lymphocytes and macrophages in melanomas and breast cancers.
Higher chance of cancer after immunosuppression i.e AIDS, ageing...


What are 5 examples of immune system escape by tumours

Low immunogenicity - No MHC ligand/ surface antigen (Breast cancer)
Tumour treated as self - Tumour antigens taken up and presented by APCs but dont stimulate T cells.
Antigen modulation - Antibody against a tumour cell - The cell surface antigen is endocytosed and degraded, immune selection for the antigen is lost
Tumour induced immune suppression - Factors secreted by tumour cells inhibit T cells directly
Tumour induced privileged site - Factors secreted by tumour cells create a physical barrier to the immune system i.e the BBB


What is active immunotherapy

typically vaccination (cervical cancer)
Purpose is to augment host immune system to tumours with cytokines and costimulators


What are types of cancer vaccine

Purified tumour antigens injected as a peptide vaccine - problem is that the peptides are unlikely to be tumour specific


What is passive immunotherapy

Adoptive T cell therapy/ anti-tumour antibodies


What are three types of cell based therapies

Can be used to activate a patients immune system to attack cancer
Used to target therapeutic genes to attack the tumour (loaded with a gene/virus)
Dont directly act on cancer cells, instead work to activate the hosts immune system


What are dendritic cells and where are they found

Found throughout the body - detect foreign material and present the antigen on their surface to lymphoid originated cells (T cells NK cells)


Describe a dendritic cell vaccine

Take blood from the patient. Isolate monocytes and differentiate them into DC. Pulse the DC with the toxic payload (tumour antigen) and return them to the body. Circulate to lymphoid organ and present to CD4/CD8 T cells.


How is the trojan horse treatment performed

Take blood from the patient and isolate the monocytes
These will differentiate into macrophages and are associated with a toxic payload (in this case a virus) and are put back into circulation. It's known that they translocate deep into tumours and release the toxic payload.


Why are areas of hypoxia targeted

Tumour hypoxia associated with poorer prognosis:
Hypoxic conditions stimulate new vessel growth, suppress cytotoxic T cells and are resistant to radio/chemotherapies (this will lead to relapse of the tumour)


Would the macrophage therapy be a frontline treatment?

No, used following chemo/radiation therapy - After these macrophages are found in the hypoxic tumour site that remains so can kill off any surviving cells


What were the results from the trojan horse therapy in the mouse model

Dual therapy with DOX kept primary tumour size to a minimum whilst also reducing the number of lung metastases


How do you ensure that the macrophages produced reach the tumour site

Magnetise the macrophages by giving the macrophages iron - Then use a magnetic field and apply it to an area near to the tumour.
For deep tumours, potential of magnetic focusing on areas from MRIs