Lecture 1 Flashcards
Forward Grouping
Detection of antigens on patients RBCs using known commercial antisera
Reverse Grouping
Detection of ABO antibodies in serum of patients using known commercial RBCs
What is the most common blood types
A+ and O+
ABO antibodies are
IgM
Activate complement
React at room temperature or colder
At what point are ABO antibodies too low to detect?
~3 to 6 months of age
because some, or all, of the antibodies present may be IgG maternal antibodies that have crossed the placenta
When does antibody production peak?
between 5 and 10 years of age
What is predominating class of immunoglobulins in group O?
IgG
What Chromosome is ABO genes found on?
Chromosome 9
What type of gene is O type
O gene is recessive
It is not expressed unless this gene is inherited from both parents (OO)
Blood group A
Antigen: A
Antibody: B
Genotype: AA or AO
Blood Group B
Antigen: B
Antibody: A
Genotype: BB or BO
Blood Group AB
Antigen: Both A and B
Antibody: None
Genotype: AB
Blood Group O
Antigen: None
Antibody: A and B
Genotype: OO
ABH Antigen: H Transferase and Sugar
Glycosyltransferase: a-2-L fucosyltransferase
Sugar: L-fucose
ABH Antigen: A Transferase and Sugar
Glycosyltransferase: a-3-N-acetylgalactosaminyltransferase
Sugar: N-acetyl-D-galactosamine
ABH Antigen: B Transferase and Sugar
Glycosyltransferase: A-3-D-galactosyltransferase
Sugar: D-galactose
Where are most ABH antigens found
~25 to 50% of the number of antigenic sites found on the adult RBC
What other gene does type O have?
H gene (HH or Hh)
What gene is more present?
H gene
What H genes are rare?
Hh
hh is the most rare
hh
genotype hh is extremely rare
does not produce α -2-L-fucosyltransferase and as a result cannot add L-fucose to type 2 chain and H substance is not expressed on RBC
Bombay
term used to refer to phenotypes that lack normal expression of ABH antigens
A gene
higher concentrations of transferase than the B gene.
Results in almost complete conversion of the H antigen on RBC to A antigen sites
Which type has the most antigenic sites?
A1: 810,000 to 1,170,000 antigen sites
What is SeSe or Sese?
Secretor gene
codes for the production of a transferase, results in the modification of the type 1 precursor substance in secretions to express H substance
sese
People who inherit the sese genotype are termed non-secretors
Type A1
RBCs that react with both anti-A & A1
Type A2
RBCs that react with anti-A and not anti-A1
immunodominant sugar on both A1 & A2 RBCs
N-acetyl-D-galactosamine
Lectin
seed extracts that agglutinate human cells with some degree of specificity
Agglutinates A1 or A1B cells
does not agglutinate A2 or A2B cells
Dolichos biflorus
source of anti-A1 Lectin
