[asa] PSCF article on immune system

From: Craig Story <Craig.Story@gordon.edu>
Date: Sat Dec 05 2009 - 20:34:47 EST

There must be a way to directly reply to a thread in this listserv, but I
just subscribed, and am happy to see people discussing my article.

Let me briefly comment on two paragraphs from Bill Powers:

³It must be something like any search program. You will have to get
"close" before a random search becomes useful. You might begin your
search "randomly", but there must be some sort of guiding mechanism that
quickly narrows or directs the search, e.g, gradient search.

I suspect, from what Craig says, that the search is guided by a "memory"
of previously generated antibodies, which may be why mother's milk is so
important for the survival of children, or colostrum for the survival of
baby goats, cows, etc.²

One must keep in mind that the variety of specificities is continually
generated whether or not there is an actual pathogen present. Then selection
occurs as necessary. Some optimization (affinity maturation) occurs after
³hits² are found that bind the antigen reasonably well.

Second, the memory of past useful antibodies (such as the ones that might be
partially protecting some of us from H1N1 flu right now) are stored as cells
that remain alive for many years. As for motherıs milk, etc, it is the fact
that the baby is in the same environment as the mother, and exposed to the
same pathogens, that her useful IgA/IgM antibodies go into her milk. In the
case of cows and rodents, actually itıs IgG that is in the colostrum/milk,
respectively (the topic of my PhD thesis). For humans, milk has IgM mostly,
but the principle is the same. This transferred antibody is considered
_passive_ immunity, since it is only protein, and has a half-life, etc. It
takes some time after birth for the newborn to be able to generate its own
cellular responses. In your comment it sounded a bit like you were
suggesting that the transferred antibodies are somehow guiding the future
cellular responders. That may be true to the extent that immune networks*
are happening, but in my opinion, that is probably not be the major factor
in immune repertoire development. I think of transferred Ab as just a
passive, temporary solution to pathogens in the immediate environment only,
not something that ³guides² the immune system. -CS

* ³Immune networks² means something like the following: An anti-antibody is
made that has same 3D shape as antigen, then an anti-anti-antibody is made
that again can react against the original antigen. This is so-called
idiotypic network theory. Not something Iım really eager to get into. Cool
idea though. The problem is to get an immune response you need all that
³damage² signal and probably that spells trouble for the idiotypic network,
although never write something off completely in science, especially
immunology, it might appear later.

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Received on Sat Dec 5 20:41:10 2009

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