Self/nonself discrimination

Shiv A. Prasad MicroBio shiv at
Tue Jul 19 13:13:12 EST 1994

>Frauwirth (BioKen)) says:
>>In the absence of specific antibodies (as is likely to be the case early
>>in an immune response to a "new" antigen), APC's can pick up proteins using
>>pinocytosis.  Apparently dendritic cells (in the thymus) are particulary
>>good at this.

Don responds:
>         As indicated above, I doubt tha absence of sufficiently specific
>                              Sincerely, Don Forsdyke, Discussion Leader.

OK, so dogma (i.e last review I read on DC's) states that dendritic
cells are not phagocytic and do not express FcR's.  How then would these
cells present Ag?  Are peptides merely loaded onto empty class II molecules,
do they displace class II with weakly-bound peptides, or is pinocytosis
responsible for Ag uptake?

DC's are arguably the best APC in presenting peptide Ag in vitro. And if the
Ag are seemingly rare things like KLH or GATT, it's not likely that serum-
containing media have Ab to these proteins.

Shiv Prasad
shiv at

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