Outline the principal mechanism by which tumour cells escape immune recognition

Question 1

Down-regulation of antigen presentation

Answer 1

Tumour cells reduce the expression of MHC molecules which are crucial for presenting antigens to T cells. Making it difficult for the immune system to recognise and mount an effective response against the tumour cells

Question 2

Loss of antigen

Answer 2

Downregulation/loss of antigens that are recognised by the immune system making them invisible

Question 3

Immune Checkpoint Activation

Answer 3

Tumour cells exploit immune checkpoint pathways to inhibit the activity of cytotoxic T lymphocytes.
They are able to bind to specific ligands such as PD-L1 and turn off cells

Question 4

Antigen Masking

Answer 4

Tumour cells modify or mask their surface antigens to avoid recognition by the immune system

Question 5

Induction of tolerance

Answer 5

Tumour cells may induce immune tolerance, leading to the activation of regulatory pathways that suppress immune responses.
This can involve the recruitment and activation of regulatory T cells, which suppress the activity of effector T cells

Question 6

Alteration of tumour microenvironment

Answer 6

Tumour cells modify the surrounding tissue to create an environment that is not conductive to effective immune responses.
This includes changes in oxygen levels, nutrient availability, and the release of cytokines that promote an immunosuppressive environment.