Tumour immunity Flashcards
What happens to cells when they are referred to as cancer?
- Damaged cells do not undergo programmed cell death
- Growth/replication is no longer controlled
- Cellular metabolism is altered
What is a tumour?
A swelling or lesion caused by an abnormal growth of cells
What is the difference when a tumour is cancerous?
Arises from a single cells that uncontrollably proliferates
What are the different possible causes of tumours?
- Oncogenes
- Carcinogens
- Age
- Gender susceptibility
- Immune deficiency
- Infection
What is an oncogene?
Protein encoding genes which if deregulated trigger the onset and development of cancer
Define a benign and malignant tumour
Benign - at a single site, local, cannot spread by invasion or metastasis
Malignant - forms a secondary tumour, causes tissue damage which leads to inflammation, cells invade neighbouring tissues and enter blood stream
Which types of tumours can be treated surgically?
Benign and pre-malignant
What happens when a malignant tumour is first recognised by the host?
It is seen as a wound and triggers a normal innate immune response - sends a wave of macrophages to the site
What is a neoantigen?
These can be detected in tumours by immunosurveillance, most are abnormal self-proteins, which when recognised, trigger an immune response
What are the different tumour antigens?
- Can be excessive amounts of normal proteins or tumour specific antigens
- Tumours rarely express new antigens, they are often normal proteins that are abnormal in some fashion
What response can promote tumour formation?
Inflammation
What is tumour surveillance?
A system of immunosurveillance which eradicates tumours before they can grow
Which cells are involved in targeting tumour cells found during tumour surveillance?
- Macrophage
- Dendritic cell
- CD8 cell mediated cytotoxicity
- NK cell
- Antibody dependent cell cytotoxicity
Which 3 cells are involved in tumour immunity?
Cytotoxic CD8 T-cell
Macrophages
NK cells
Which cells are relied on to recognise the tumour antigen within an MHC complex?
CD8 killer cells
Why can CD8 t-cells not cause cell death?
Tumour cells are immune
What is the role of the B-cell compartment in the adaptive immune response to tumour immunity?
B-cells are converted into plasma cells which produce antibodies specific to the neoantigen - they coat the tumour which triggers antibody dependant cell cytotoxicity (ADCC) from an NK cell
Describe ADCC activity against tumours
- Tumour antigen mediated attack by NK cells
- Innate and lack memory
What are tumour associated macrophages?
Under the control of the tumour and allow tumour maintenance
- Angiogenesis = new blood vessel development
- Tumour invasion of tissues
- Inflammation
What is immunotherapy?
Stimulating them immune system to attack tumours
Which cells/molecules are involved in non-specific immune stimulation during immunotherapy?
- Microbial products
- Cytokines = Interferons, Tumour necrosis factor, IL-2, IL-4
- Cytokine activated cells = T-cells, NK cells
What are active and passive immunisation (immunotherapy)?
Active = Inject with modified tumour cells Passive = Inject anti-tumour antibodies
