How do macrophages know what to eat?

R. Fox richfox at
Thu Feb 19 14:03:47 EST 1998

I thought if the cell expresses phoshatidylserine (PS), ie an insult to
cell membrane has caused PS to flip from inside the membrane to outside
the membrane.  This PS is then a signal for macrophage processing.

Just a thought.  And it may not be right.

On 13 Feb 1998, Axel Boldt wrote:

> Marc Buhler <mbuhler at> said:
> Axel> Neither B- nor T-cells nor anybody else will take any action unless a
> Axel> new antigen has been engulfed, processed and presented by a macrophage
> Axel> (let's talk about thymus-dependant antigens only for now); so the most
> Axel> central question of all should be: how do macrophages know what to
> Axel> engulf? 
> Marc> If antibodies are stuck to it, the macrophage can use Fc receptors (tail
> Marc> end of the antibody, as it were) to "know" they should engulf
> Marc> it. 
> At this point, we don't have antibodies. Before the B-cell can produce
> antibodies, it has to be stimulated by a Th cell, which has to find
> something on a macrophage surface. So the macrophage must know what to
> eat without the help of antibodies.
> Marc> is no need for the macrophage to choose between "self" and
> Marc> "non-self".... most *everything* should be taken in, digested and
> Marc> presented.
> That would be a possibility of course, but wouldn't that mean that
> macrophages chew on the good stuff all day and destroy valuable
> proteins and cells along the way?
> Axel

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