The terrorist inside my husband's brain

Re:The terrorist inside my husband's brain by ubernostrum on Sunday October 02, 2016 @08:32AM (#12622057)

Except that the immune system's idea of what set of molecules to accept and what set to kill is not based on a generalized idea of what a "healthy cell" looks like -- otherwise we wouldn't have such trouble matching people for organ transplants, since our immune systems would just accept any generically healthy organ.

Instead it's dependent on the (specific to the individual) set of genes controlling the major histocompatibility complex, and so is very much a "self" ("derived from my genes") versus "non-self" ("not derived from my genes") determination.

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Re:The terrorist inside my husband's brain by Confusion on Monday October 03, 2016 @03:19AM (#12625870)

Yes, what is 'healthy' looks different for each individual. That doesn't mean that something is found to be 'healthy' because it is 'self'.

The immune systems primary function is housekeeping: killing cells that are still completely 'self', but are old, worn down or dysfunctional in some other way. Killing 'invaders' and cancers is minor in terms of the numbers of cells destroyed.

As your transplant example shows: something foreign can be found to be entirely 'healthy' by your immune system. So self vs. foreign is too narrow.

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