Transcript מצגת של PowerPoint

How Does the Immune System
Tolerate its Host?
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Rapid proliferation generally held to be a survival
advantage.
Low need for nutrients generally held to be a survival
advantage.
What about both together?
Claim: Rapid proliferation can be contraindicative to
low nutritional needs, so that it becomes a liability, [even
if nutritional need per reproduction is smaller than for
competition] because total need/time increased.
Basis for self-tolerance
Antigen-provoked growth of immune cells, if too much,
yields too much reproduction, and ultimate demise.
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dNi/dt =piNi – Ksi(t)Ni
Ni =concentration of species i,
pi= reproductive rate of species i
si= strain on species i
K = death rate constant
Ksi= death rate
dsi/dt = (Ti-F), si>0
F = food supply,
Ti=nutritional need of species i
dF/dt = m –FSaiNipi,
m is rate of food input, ai is the food consumed per replication
Slowest replication,
greatest nutritional
need per replication
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Supporting facts:
“High –zone” tolerance: Too much antigen causes the
immune system to resign itself to the antigen’s presence.
All mitogens are toxic beyond some level.
Can this principle be the basis for cancer treatment?
Cancer cells generally lack checkpoints, cell cycle arrest
mechanisms, and reproduction is not slowed by nutritional
deficit as for healthy cells. Moreover, cancer cells have a
higher nutritional need per reproduction.
Should cancer patients eat less protein?