BB LEC - ABO Blood System Flashcards
most important system in transfusion and transplanta1on therapy
ABO BLOOD GROUP SYSTEM
the only blood group system in which individuals have an1bodies in their serum to an1gens that are absent from their RBCs
ABO BLOOD GROUP SYSTEM
drew blood from himself and five associates, separated the cells and serum, and then mixed each cell sample with each serum. He was inadvertently the first individual to perform forward and reverse grouping.
Landsteiner
• __ genes are dominant than O gene
A and B
__ genes are codominant
A and B
ABO genes are located on chromosome
9
ABO genes are inherited in a what manner following simple Mendelian genetics laws
codominant
H gene codes for what glycosyltransferases
L-fucosyltransferase
A gene codes for what glycosyltransferases
N-acetylgalactosaminyl- transferase
B gene codes for what glycosyltransferases
D-galactosyltransferase
Immunodominant sugar of H gene
L-fucose
Immunodominant sugar of A gene
N-acetyl-D- galactosamine
Immunodominant sugar of B gene
D-galactose
how many percent of all individuals possess the H gene.
99.99%
The forma1on of ABH antigens results from the interaction of genes at three separate loci what are these loci
(ABO, Hh, and Se)
A, B, and H an1gens are formed from the same basic precursor material called
(called a paragloboside or glycan)
On the __ day of fetal life, attachment of immunodominant sugars occurs on the RBC membrane and it is dependent on ABH genes inherited.
37th
antigens fully developed by what age
2-4 YEARS
is actually the precursor structure on which A and B an1gens are made
H antigen
The ___ genes are closely linked and located on chromosome 19
H and Se
The H and Se genes are closely linked and located on chromosome ?
19
what gene must be inherited to form the ABO antigens on the RBCs
H
what gene must be inherited to form the ABO antigens in secretions.
Se
what type of precursor substance
terminal galactose on the precursor substance is attached to the N-acetylglucosamine in a beta 1 → 4 linkage
type 2
what type of precursor substance
beta 1 → 3 linkage between galactose and N-acetylglucosamin
type 3
ABH antigens on the RBC are constructed on oligosaccharide chains of a type ?? precursor substance.
2
- are mostly naturally occurring antibodies that are
detectable 3 to 6 months after birth following exposure to ABO-likeantigensin theenvironment
ABO ANTIBODIES
ABO ANTIBODIES detectable when??
3 to 6 months after birth following exposure to ABO-likeantigensin theenvironment
are mostly IgM and react best at RT or below.
ABO ANTIBODIES
most anBbodies found in cord blood serum are of ?? origin
maternal
Antibody production peaks when an individual is between___ years of age and declines later in life.
5 and 10
Although anti-A (from a group B individual) and anti-B (from a group A individual) contains predominantly IgM antibody, there may be small quantities of __ present.
IgG
___ antibody is not a combination of anti-A and anti-B but is a separate “cross-reacting” antibody that is usually IgG in nature
Anti-A,B
Predominant Ig in Anti-A,B
IgG
ABO Ab activate complement at what temp?
37C
is defined as using known sources of commercial antisera (anti-A, anti-B) to detect antigens on an individual’s RBCs.
Forward grouping
is defined as detecting ABO antibodies in the patient’s serum by using known reagent RBCs, namely A1 and B cells.
Reverse grouping (back type)
Testing RBCs with reagent __ is not required as a routine part of ABO testing.
anti-A,B
However, some believe that ___ is more effective at detecting weakly expressed A and B antigens than reagent anti-A or anti-B
anti-A,B
However, the production and use of _____have made anti- A and anti-B reagents much more sensitive, to the point where weak A and B antigens can be detected routinely.
monoclonal antisera
. It is still routinely used when performing ABO confirmation of blood donors, because it is more economical to use one reagent (anti-A,B) than to use two reagents (anti-A and anti-B) to verify group O donor units.
Anti-A,B
Reagent anti-A,B can be prepared using : (3)
blended monoclonal anti-A and anti-B; polyclonal human anti-A,B; or a blend of monoclonal anti-A, anti-B, and anti- A,B.
It has been postulated that ____ are chemically similar to A and B antigens.
bacteria, pollen particles, and other substances present in nature
Antibody production in most OTHER blood group systems requires ___ by transfusion or pregnancy
the introduction of foreign RBCs
_____ is unique to the ABO blood group system.
performance of serum grouping
- regulates the formation of H antigen and subsequently, of A and B antigens in secretory cells
WHAT SYSTEM
Sese system
WHAT SYSTEM
- regulates production of H antigens on erythrocytes
Zz system
Regulating gene for ABH Antigens
FUT1 (Zz gene)
Regulating gene for ABH Soluble susbtances
FUT2 (Se gene)
name of Zz gene
FUT1
name of Se gene
FUT2
1st sugar in the precursor substance
of ABH Ag
glucose
1st sugar in the precursor substance
of ABH Soluble substances
N-acetylgalactosamine
: represent phenotypes that show weaker variable serologic reactivity with the commonly used human polyclonal anti-A, anti-B and anti-A,B reagents
ABO SUBGROUPS
who described two different A antigens based on reactions between group A RBCs and anti-A and anti-A1
von Dungern
The __ subgroups are generally more common than B sub- groups
A
___ is found in greatest concentration on the RBCs of group O individuals
H antigen
for the base of formation of H, Lewis, I/i, P1 antigens
common carb structure (antigen building block)
2 terminal sugars in the oligosaccharide chain
D-galactose and N-acetylglucosamine
only antigen in H blood group system
H antigen
amorph of the H locus, with rare frequency
h
gene product of H allele
transferase enzyme
Gene products of the ABO alleles require __ to be the acceptor molecule
H antigen
The FUT1 gene adds galactose to both oligosaccharide chains in red cells and in secretions. TRUE OR FALSE
TRUE
alleles in ABO locus
A, B, O
nonfunctional ABO allele
resulting gene is an enzymatically inactive protein
O allele
defined the molecular basis of the ABO phenotypes
Yamamoto
