Blood Groups/Types

Exam 2

blood groups (8)

A+/A-

B+/B-

AB+/AB-

O+/O-

(more groups than shown 8, but these are the standards)

What are the differences between antigens versus antibodies?

antibodies → come from an immune response, fighting infections

antigens → proteins/sugar combo that sits on top of cell as an identifier (distinguishes cell)

are both related to cell structure and cell signaling

antigens generate antibodies

What do erythrocytes contain on their external surfaces?

glycoproteins (individualized; which ones appear in combination depends on the individual)

What are the properties of the glycoprotein antigens?

unique to the individual

recognized as foreign (not belonging) if transfused into another individual

What are the problems associated with foreign antibodies and transfusions?

Can share antigens with someone even if foreign

Wrong antigens can generate immune response (if body expects antigen, won’t generate IR; if not, will generate IR)

Need to be careful

What allows for blood group classification?

Presence or absence of these surface antigens

8 standard blood types shows what antigens are present or not

What are common antigens seen on red blood cells?

A, B, Rh

(many individuals may have Antigen A) (combo is what is limited)

(most individuals will not get tested for other antigens than the standards)

How many varieties of naturally occurring antigens do humans have?

30

Why are ABO and Rh antigens normally used?

They cause vigorous transfusion reactions when they are improperly transfused.

What is a transfusion reaction?

Clumping in blood (when wrong transfusion)

Generates serious response

What are other blood groups besides the standards?

M, N, Dufy, Kell, Lewis

Mainly used for legalities

(normally not tested for; may cause mild reaction and concerns individuals with regular transfusions)

What is the structure of H antigen?

galactose (gal) → fucose (fuc)

(everyone has fuc)

gal, fuc

What is the structure of A antigen?

galactose (gal) → N-Acetyl galactosamine (NAG)(galnac) & fucose (fuc)

gal, NAG, fuc

What is the structure of B antigen?

galactose (gal) → galactose (gal) & fucose (fuc)

gal, gal, fuc

What differentiates H, B, A antigens?

Positioning of galactose (gal) → determines immune response

Galactose is present at beginning of chain for all three, followed by differing sugars

What causes antigen-antibody reaction?

Will only occur if antigens are injected into an individual that normally does not have those antigens → antibodies are generated

What do antibodies do during an antigen-antibody reaction?

immune system antibodies will trigger agglutination (clumping) of blood cells

when AB is recognized → AB binds to antigen

antigens are referred as agglutinogens for this reason

What is the structure of an antibody?

Constant domain (body)

Variable domain (V-shaped top)

Variable domain at ends has space for antigen to bind too (both sides)

How can variable domain binding cause clumping?

If variable domain end of antibody binds to two different red blood cells.

Brings together different ones, causes clumping.

What are the most common blood group?

A, O

What is the least common blood group?

AB, B