Lecture 5 - Tumor immunology Flashcards
(86 cards)
explain the concept of ‘immune surveillance of cancer’?
a physiologic function of the immune system is to recognize and destroy clones/ trasformed cells before they form tumors, and kill tumors once they’re formed
t/f: both adaptive and innate immune systems fight against tumor formation, which has been proven by both animal and human studies
true
do tumors possess antigens?
yes - this is how they can be recognised as non-self
t/f: immune responses frequently fail to prevent tumor growth
true
why is the immune surveillance of cancer a field of interest in medical science? Why not just focus on treatment types?
because it is a potential treatment type - the immune system can be activated by external stimuli to kill tumor cells
Can tumors stimulate immune responses - considering they have formed from the hosts own cells?
Yes
How can immune cell presence and tumors be linked, in terms of prognosis of disease?
If a tumor is surrounded by many mononuclear cells (lymphocytes, NK cells, macrophages - involved in adaptive response) it implies a more positive prognosis (they might fuck that thing upppp!)
define immunoscore?
The Immunoscore is a method to estimate the prognosis of cancer patients, based on the immune cells that infiltrate cancer and surround it - higher immunoscore, lower clinical impact :)
State the principal means by which the adaptive immune system kills tumor cells?
CD8+ cells (cytotoxic T cells)
CD8+ cells are likely to kill which…
a. ) Cells overexpressing MHC II
b. ) Cells not expressing MHC II
c. ) Cells expressing MHC I
d. ) Cells not expressing MHC I
c
t/f: CD8+ cells do not perform any type of surveillance function
false - they do, looking for who has MHC I to kill
what’re CD8+ cells which are found inside tumors called? What’s their function?
Tumor-infiltrating lymphocytes; have capacity to kill tumor cells
Tumor specific CD8+ cells are often difficult to detect within patients. Why may this be?
due to regulatory mechanisms undergone by tumor cells - they prevent specific CD8+ formation by inhibitory pathways
Tumor cells undergo inhibitory pathways to prevent the formation of CD8+ cells which would specifically target them. How can this problem be solved? (simple answer)
the inhibition of these inhibitory pathways by the tumor (disinhibition), this leads to large CD8+ cell response!
NK cells kill (many/ few) types of tumor cells
many; variable
NK cells kill tumor cells which exhibit what?
- reduced MHC class I
- ligands for NK cell activation
state the 3 possible outcomes of natural immunosurveillence applied to a premalignant lesion (tumor)?
- Tumor escapes, metastases
- Equilibirum, tumor remains same size
- Elimination, tumor destroyed
what is another name for CD8+ cells?
CTL - cytotoxic lymphocyte
what does the immunoscore consider?
- immune cell type (CTL’s & memory cells good)
- immune cell quantity (more the better)
- density (denser the better)
- location (inside tumor and outside better)
- immune functional orientation (what functions the cells have)
- immune gene signatures
the immunoscore considers immune functional orientation. What is the desired functional orientation for fighting off tumors?
- TH1 cells to stimulate cellular response
- cytotoxic factors (granzymes, IFN-Y, IL-12/15)
- chemokines to attract adaptive immune cells
explain the relationship between CTL’s (CD8+ cells), NK cells and MHC class I?
CTL's kill cells which express MHC class I NK cells kill cells which do not possess MHC class I
(cells = pathogenic only, obvs not all cells)
which cell is the “bridge between innate and adaptive immunity”?
(he said it like 5 times in this lecture so its gotta be worth sumn)
NK cells
t/f: NK cells do not kill virally infected cells
false
why do NK cells only kill cells not expressing MHC class I?
Because MHC class I sends inhibitory signals to NK cells