Cancer And The Immune System

Question 1

What can immunotherapy do?

Answer 1

• Enhance immunity in patients with cancer and chronic infection
• Induce tolerance in autoimmune diseases
• Develop therapies for inherited diseases

Question 2

Which directions can oncogenic evolution go once cells are transformed?

Answer 2

• > elimination due to immunological surveillance
• > Immune resistance is selected for resulting in equilibrium with the immune system (tumour dormancy). Escape from the immune system causes progressive disease and malignancy

Question 3

Which vaccines protect against cancers?

Answer 3

HBV- Hepatitis B- liver cancer

HPV- cervical cancer

Question 4

Describe immune checkpoint inhibition

Answer 4

• T cells have inhibitory receptor PD-1, so when tumour cells start expressing PD-L1 the T cells are inhibited despite seeing tumour antigen
• Blocking this Cis-negative regulation can be achieved by antibodies Anti-PD-1 or Anti-PD-L1

Question 5

Describe therapy with tumour infiltrating lymphocytes (TIL)

Answer 5

• Tumour excision and growth of tumour fragments with IL-2-> expansion of T cells present in tumour micro environment- some level of tumour specificity
• selection then expansion and TIL infusion into patient
• Effective in 60-70% melanoma patients

Question 6

Outline therapy with engineered T cells

Answer 6

• Isolate T cells from blood then viral gene transfer of TCR or CAR (chimeric antigen receptor) into PBMC (peripheral blood mononuclear cell- lymphocytes and monocytes)
• Retroviral gene transfer- clone DNA of antigen specific TCR and insert into retro-viral vector then into T cells
• Cells expanded in vitro then given to patient
• CAR vs TCR- made in lab, can only recognise cell surface antigens unlike TCR

Question 7

What is the most successful tumour associated antigen to target?

Answer 7

CD19- expresses by many patients and cancer types