white_o
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Pleeeease can someone explain how AB is a universal recipient even though it has antigen A and B which would react with the A antibodies in B and O? Also how is O a universal donor if it too has antigens A and B which can react with antibody A in A and antibody B in B???? Pleeeeaae help thanks!!
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Kinkerz
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You've completely misunderstood what's going on here.

You make antibodies against antigens that you don't have.

So if someone has type O blood, they'll make antibodies against antigens A and B. Therefore if you were to give someone with type O a transfusion from someone with type A, B or AB, those transfused red blood cells would be destroyed by the host (Mr/Miss type O) immune system. However, because type O has no antigens, it can be given to any of the others, hence the term universal donor.

If someone has type AB, it means they won't make antibodies against any of the antigens, because their immune system is tolerant. If it wasn't, the host's immune system would destroy its own red blood cells. This means that they can receive blood from A, B, AB and O, hence the term universal recipient.
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white_o
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(Original post by Kinkerz)
You've completely misunderstood what's going on here.

You make antibodies against antigens that you don't have.

So if someone has type O blood, they'll make antibodies against antigens A and B. Therefore if you were to give someone with type O a transfusion from someone with type A, B or AB, those transfused red blood cells would be destroyed by the host (Mr/Miss type O) immune system. However, because type O has no antigens, it can be given to any of the others, hence the term universal donor.

If someone has type AB, it means they won't make antibodies against any of the antigens, because their immune system is tolerant. If it wasn't, the host's immune system would destroy its own red blood cells. This means that they can receive blood from A, B, AB and O, hence the term universal recipient.
But O has both antibodies? So won't the A antibody react with the A antigen in A?
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Larynx.pharynx
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(Original post by Qaiys)
But O has both antibodies? So won't the A antibody react with the A antigen in A?
When blood is donated, it's separated so only the red blood cells are given, not containing serum antibody.
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white_o
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(Original post by Larynx.pharynx)
When blood is donated, it's separated so only the red blood cells are given, not containing serum antibody.
omg really?? That's literally the answer to all my questions!! THANK YOU SO MUCH<3<3<3 why didn't it say this in my revision guide?!!?
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DorianGrayism
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(Original post by Qaiys)
Pleeeease can someone explain how AB is a universal recipient even though it has antigen A and B which would react with the A antibodies in B and O?
Because AB people do not make antibodies against A or B antigens.

If they did, they would destroy their own blood.

They only make antibodies against foreign antigens. A and B antigens are not foreign to people with AB blood.

So they can receive A or B.
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lifescomplexity
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(Original post by Qaiys)
But O has both antibodies? So won't the A antibody react with the A antigen in A?
Ah, I see what you've done

Yes O does have both antibodies; as the other poster said, that's why it will reject A, B or AB blood that is transfused into it. (O also has no antigens, though.)

But the antibodies are in NOT 'carried away with the blood', as it were - they are part of the body. It's antigens that go 'with the blood', if you see what I mean. So when O is transfused to someone with type A blood, to use your example, there will be no reaction because O has NO ANTIGENS to react with the type A blood's ANTIBODIES.

So basically, it's the antigens from the 'host' blood that react with the antibodies from the transfused blood, not the other way around as you thought - that's why you were confused so type O antiBODIES don't have any effect on type A blood because it's antiGENS that react with blood and agglutinise it.

I hope that that made sense and helped you out :s are you doing GCSE Bio OCR Gateway science B, B4-6 tomorrow? Bc I am and have also been revising this


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Larynx.pharynx
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(Original post by lifescomplexity)
Ah, I see what you've done

Yes O does have both antibodies; as the other poster said, that's why it will reject A, B or AB blood that is transfused into it. (O also has no antigens, though.)

But the antibodies are in NOT 'carried away with the blood', as it were - they are part of the body. It's antigens that go 'with the blood', if you see what I mean. So when O is transfused to someone with type A blood, to use your example, there will be no reaction because O has NO ANTIGENS to react with the type A blood's ANTIBODIES.

So basically, it's the antigens from the 'host' blood that react with the antibodies from the transfused blood, not the other way around as you thought - that's why you were confused so type O antiBODIES don't have any effect on type A blood because it's antiGENS that react with blood and agglutinise it.

I hope that that made sense and helped you out :s are you doing GCSE Bio OCR Gateway science B, B4-6 tomorrow? Bc I am and have also been revising this


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This isn't strictly true. A person with type O blood has A and B antibodies in their blood, but these are seperated out via centrifuging. When red blood cells are given to a person, it doesn't need to be considered what antibodies their donor had, because they are not present. However, if plasma is given, that needs to be considered, because antibodies are present in plasma.
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DorianGrayism
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(Original post by Qaiys)
Also how is O a universal donor if it too has antigens A and B which can react with antibody A in A and antibody B in B???? Pleeeeaae help thanks!!
Blood group O has no antigens on the surface.

If you have no antigens on the surface then the body cannot create antibodies against it to destroy it.

Therefore, it can be given to anyone.
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DorianGrayism
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(Original post by Larynx.pharynx)
This isn't strictly true. A person with type O blood has A and B antibodies in their blood, but these are seperated out via centrifuging. When red blood cells are given to a person, it doesn't need to be considered what antibodies their donor had, because they are not present. However, if plasma is given, that needs to be considered, because antibodies are present in plasma.
Ok but I think in the GCSE exam, they are not looking for this.

They want people to understand the principle of the grouping system.
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white_o
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(Original post by lifescomplexity)
Ah, I see what you've done

Yes O does have both antibodies; as the other poster said, that's why it will reject A, B or AB blood that is transfused into it. (O also has no antigens, though.)

But the antibodies are in NOT 'carried away with the blood', as it were - they are part of the body. It's antigens that go 'with the blood', if you see what I mean. So when O is transfused to someone with type A blood, to use your example, there will be no reaction because O has NO ANTIGENS to react with the type A blood's ANTIBODIES.

So basically, it's the antigens from the 'host' blood that react with the antibodies from the transfused blood, not the other way around as you thought - that's why you were confused so type O antiBODIES don't have any effect on type A blood because it's antiGENS that react with blood and agglutinise it.

I hope that that made sense and helped you out :s are you doing GCSE Bio OCR Gateway science B, B4-6 tomorrow? Bc I am and have also been revising this


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Thankyou!! And yup hahaha I am :P good luck!!!
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lifescomplexity
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(Original post by Qaiys)
Thankyou!! And yup hahaha I am :P good luck!!!
good luck to you too!!


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