Can apoptotic cells represent "danger" to the immune system?

mark mark.haynes at
Thu Feb 4 17:32:18 EST 1999

Ian A. York wrote:

> The problem is that "normal" apoptosis is fuzzy. 

That was exactly what i was referring to. I'll go look up the paper to see 
what they did but the idea was along the lines of this.  Does all apoptotic 
cells die the same way?  Is activation induced apop. the same as dying by 
neglect and when i say the same i realy mean exactly the same. So i agree 
apoptosis may be fuzzy.

> Is there "abnormal"
> apoptosis?

Possible yes.

>  It's clear that apoptosis cells can induce an immune response;
> see, for example, J Immunol 1998 Nov 1;161(9):4467-71 (our journal club
> selection for today, so I have it in mind), and several other papers.  But
> the authors of this paper, like those of some of the other papers, have
> then concluded that this is consistent with the danger hypothesis because
> the apoptosis needed to be *abnormal* in quantity (i.e. there had to be an
> excess of apoptosis cells over DC to get the response).

Again ill look at the paper.

> Now this isn't illogical, and it's not an unreasonable idea; but you see
> my point, I think.  There was, in fact, a prediction there; it was, in
> fact, falsified, because apoptotic cells did induce the immune response;

I agree with you.  From the review in annals the discussion definetely was 
that apoptosis isn't dangerous therfore no responsivity, but in vitro isn't 
in vivo and that might be another technical glitch.

> but that did not falsify the theory, because a post-hoc explanation was
> provided.  Again, I don't object to the explanation itself, but I'm not
> enthusiastic about the sense that the theory itself is not falsifiable.


> I don't think we need a paradigm at all, personally.

But that is the general scientific method mode that we were trained in and 
thats why i don't react about it its the reductionist dogma that tries to fit 
observations into a plan/scheme etc.

>  The immune system
> wasn't a grand design, it's an ad hoc collection of things that worked
> throughout ones' ancestors' lives.  We happen to lump this mishmash of
> things into something we call an "immune system", but putting a name to
> something doesn't mean it's an entity, or even two or three entities.

That is for another discussion.  I'm gonna stop my PCR. 

> Where does your fist go when you open your hand?

To the land of ZEN.

>  And does a dog have
> Buddha nature?

my has karma is that close?

> I'd better leave it at that, I'm waxing philosophical.

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