WEEK 5: CANCER IMMUNOLOGY AND IMMUNOTHERAPY Flashcards
what are the genes called that can mutate DNA causing cancer?
oncogenes
what are the 2 types of oncogenes?
v-onc (virus oncogenes)
c-onc (cellular oncogenes)
what is the function of a proto-oncogene?
its a gene involved in normal cell growth
when a proto-oncogene is disregulated, what does it become?
oncogene
what is the role of tumour suppressor genes?
inhibit cellular proliferation and regulate programmed cell death
how many mutations does a cell need to transform from a normal to a malignant cell?
1-10
how are tumours detected by T cells?
- tumour-specific transplantation antigen (TSTA) (antigens only expressed by tumours)
- mutated normal antigens
- antigens expressed at wrong stage of cell growth
- over expressed antigen
how do tumours prevent CTL recognition?
MHC or TAP recognition
can macrophages recognise tumours?
yes
how do macrophages destroy tumours?
when hyperactive ! , they produce TNF alpha which destroy blood vessels and causes tumour necrosis
how do NK cells target cancer cells?
target cells with low levels of MHC i and unusual surface proteins.
why can the antibody immune response be ineffective in destroying a tumour?
anti-tumour antibodies can block CTL response, consequently enhancing growth
what’s the difference between a v-onc and a c-onc?
v-oncs occur from viruses inserting DNA into our own sequences causing over growth in cells. C-oncs are genes in normal healthy cells that have mutated and then cause more growth than they should.
What is meant by immune surveillance?
Immunological surveillance is a monitoring process of the immune system to detect and destroy virally infected and neoplastically transformed cells in the body.
what is a monoclonal antibody?
man made antibodies - they all bind to the same epitope so are identical
name 3 monoclonal antibodies used in cancer therapy
- antibody CD20 (CD20 found on cancerous B cells)
- herceptin (binds to HER-2)
- mylotarg (binds to CD33)
- ipilimumab
what is meant by passive therapy?
the transfusion of antibodies
what antigens are targeted by the immune system on tumours?
tumour rejection antigens
how does ipilimumab work?
it blocks negative signalling from CTLA-4 on T cells - stops the T cell being turned off
why do tumour rejection antibodies appear on cells?
peptides of tumour cell proteins are presented to T cells by MHC molecules
which 2 oncogenes are responsible for cervical cancer?
E6 and E7
what are some of the ways in which vaccines work?
- give the antigen as a protein in the vaccine
- give the genetic material to the body as a virus
what do adjuvants do?
make the tumour site more pro inflammatory which will activate macrophages which then activate T cells.
what are the cons of cytokine therapy?
cytokines don’t stay in one area and may diffuse into other areas
