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Old 06-29-2011
Mashee's Avatar
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Immunology Self tolerance versus autoimmunity misconeptions!

Hey guys I have a question...Im a little confused...in rheumatic fever the B cells produce antibodies against the Group A beta hemolytic streptococci, which have M protein that is similar to our own cardiac muscle, so those antibodies cross react with our own heart. BUT if the antigens in the bacteria resemble our own heart muscle then why doesnt our immune system recognize the bacterial antigens as SELF and NOT elicit an immune response?...

Please I may have missed some important point could someone clarify it for me?
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Old 06-29-2011
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It's an issue of specificity.

The body recognize the bacteria as foreign and sets itself to recognize the amino acid sequence but then any "similar sequence" "not exactly the same" "heart muscle" would be attacked once B cell memory is established.
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Old 07-10-2011
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Quote:
Originally Posted by Tal3at View Post
It's an issue of specificity.

The body recognize the bacteria as foreign and sets itself to recognize the amino acid sequence but then any "similar sequence" "not exactly the same" "heart muscle" would be attacked once B cell memory is established.
Ok now i get it see i was going thru UWorld today n i found Antigenic Mimicry. From what i understood it is possible that an organism be thought of as self IF its amino acid sequence is exactly the same as our own. Then there would be no immune response to that organism. But as Talat says if there is a similar sequence not exact then our immune system would attack both...
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