Immunology to Fight Cancers?

[Ken Frauwirth BioKen]

In article <4clhdn$8og at news.euro.net>, Bayu Prawira <bayu at euronet.nl> wrote:
>
>Would you like to share about how is the progress and what are the
>problems? And whether some articles from your research have been
>published?
>
>According to my opinion, -as a non-researcher-, the primary cancer
>cells can survive from immunology reaction of the body because they
>grow very slowly at the beginning, allowing them not to trigger the
>immune system at the alarming state, and most probably they develop
>something to cover up their membrane cells to the immune system
>recognition. But I believe all cancer cells can be recognised as alien
>cells if they are exposed to the body in quite a big quantity and
>uncovered. I think it may be good to 'wash' the cells carefully and to
>kill the cells without destructing them before preparation.
>
>I believe you also have thought about it and have done it. What I want
>to know is your comments.
>
>Bayu P. Hie, MD
>


Actually, I suspect that the main reason cancer cells can escape immune
surveillance is that they are nearly identical to normal cells.  In order 
for lymphocytes (T cells, B cells, NK cells) to detect and destroy a cancer
cell, it must have a *cell-surface* difference from normal cells.  And in order
to trigger a T cell response, this difference *must* occur in an MHC/peptide
complex.  Even then, the differences may be subtle enough to be ignored in the
absence of tissue damage, which increases the overall sensitivity of the immune
system.

It is obviously difficult to study these things in humans (who wants to
volunteer to be injected with *more* cancer cells?), but they have been 
studied extensively in mice.  Injecting tumor cells from one mouse into 
another mouse of the same strain (mice from the same inbred strain are 
essentially genetically identical) does not generate an immune response, 
but rather gives the second mouse cancer, unless the tumor cells are altered
first.  The trick is to alter the cells in such a way that the immune response 
can then attack the original (unaltered) cells.  It is a fine line, and no 
single method has been found that works for all tumor cells.  Those that I know
to work for at least some tumor cells all involve making the subtle differences
more likely to invoke a response: causing the tumor cells to secrete 
cytokines (TNF's, IL-4, etc.) or making them express the co-stimulatory 
molecule B7 are two examples.

BioKen
-- 
Ken Frauwirth (MiSTie #33025)                         _           _
frauwirt at mendel.berkeley.edu                         |_) *    |/ (_ |\ |
http://mendel.berkeley.edu/~frauwirt/HomePage/       |_) | () |\ (_ | \|  
DNRC Title: Chairman of Joint Commission on In-duh-vidual Affairs