antibody, antigen

[amar21]

can someone take a stab at explaining this to me.. maybe a good way to memorize to remember it

i always thought the body produced antibodies... and thus anything that didnt match the antibody would get eliminated... but for blood types its antigen.. and we have anti-antibodies?

I did a passage on antibodies being injected from a rat into a human and i got totally dominated by it... so, if anyone can take a stab at explaining exactly how antibodies and antigens relate, i would forever be grateful!

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[FutureInternist]

can someone take a stab at explaining this to me.. maybe a good way to memorize to remember it

i always thought the body produced antibodies... and thus anything that didnt match the antibody would get eliminated... but for blood types its antigen.. and we have anti-antibodies?

I did a passage on antibodies being injected from a rat into a human and i got totally dominated by it... so, if anyone can take a stab at explaining exactly how antibodies and antigens relate, i would forever be grateful!

You are correct in the basic premise that whatever does not match the body gets eliminated. Anti-bodies are one of the ways that the body identifies self from foreign. If an antibody (Ab) attaches to something it is an antigen, however in autoimmune diseases that antigen is a self protein (i.e. The body messed up & produced an Ab that binds to, and hence helps kill, your own protein)
As an example, Rheumatoid arthritis is an autoimmune dz in which you make IgM against the Fc portion of IgG (Yes an anti-antibody ). This is the trade-off for making all the anti-E.coli, anti-Staph etc Abs....somewhere down the line is the potential for messing up & the body turns on itself.

Don't know if you had an immuno course or not so maybe a little background before getting into blood groups.
When you are initially exposed to a bacteria (an antigen) your body takes approx 7-10 days to make IgM against it. This is called a Primary Response. However, the second time you are exposed to the same thing your body makes IgG & does so a lot faster (Thanks to memory B cells). This is called a secondary response.
Now since quick production of Abs must be preceded by a PRIOR exposure to an antigen, why is it that a O- person gets a rxn as soon as they are given A+ blood....beats me (and immuno teachers in medical school as well ). There are several theories one of which is that a O- person has bacteria in their gut whose proteins look like A+,B+ (and O- but that is not important) so in killing those look-alike bacteria your body ended up making anti-A+, & anti-B+ Abs hence giving a secondary response even with the very first mismatched blood transfusion.

Hopefully this makes sense. If not, post any Qs here.

p.s. Kudos on the (I assume) unintentional pun of rats getting "injected" and someone taking a "stab" at this...........(I'm such a nerd )