Secretor Flashcards
The mechanism of secretor status expression is linked to the presence or absence of soluble A, B, and H antigens in…
bodily fluids
• This expression is determined by the inheritance of specific genes at the secretor locus.
Secretor status
Type 1:
Type 2:
Body Fluids and Secretions
Red Blood Cells*
Linkage
Type 1:
Type 2:
B1-3
B1-4
Individuals who inherit at least one copy of the _______are classified as secretors.
Se allele (genotypes SeSe or Sese)
The Se allele codes for
fucosyltransferase 2 (FUT2)
______ is an enzyme that adds L-fucose to type 1 oligosaccharide chains in secretory glands.
It may also act on type 2 chains in the secretory glands.
FUT2
This addition of fucose results in the expression of soluble antigens in secretions like: DUBSTAMP
Digestive fluids
Urine
Bile
Saliva
Tears
Amniotic fluid
Milk (Breast milk)
Pathologic fluids (Exudate)
• The _______ allele is an amorph, meaning it does not produce a functional enzyme.
se allele
NON-SECRETOR GENE (se)
• Individuals with the genotype____ are classified as non-secretors
sese
As a result,_____cannot convert glycoprotein antigen precursors to soluble H substances.
Thus, they have neither soluble H antigens nor soluble A or B antigens in their body fluids
non-secretors
• Inhibit the capacity of the their corresponding antibodies to agglutinate the red cell antigens
HEMAGGLUTINATION-INHIBITION REACTION
HIR
• No agglutination (negative reaction) =______
Secretor (because the antibodies are neutralized by the soluble antigens).
HIR
• Agglutination (positive reaction) =
______
Non-secretor (because no soluble antigens are present to neutralize the antibodies).
PROCEDURE
SECRETOR STATUS DETERMINATION
STEP 1: COLLECTION OF SALIVA SAMPLE
• The individual provides a saliva sample (_____), which may contain soluble ABO blood group antigens.*
STEP 2: PREPARATION AND TREATMENT OF THE SAMPLE
• The saliva is ______to destroy enzymes and remove interfering proteins.
After cooling, the sample is centrifuged (10 minutes), and the
_____ (antigen-containing fraction) is collected.
2mL
heated in boiling water for 10 minutes
supernatant
PROCEDURE
STEP 3: INCUBATION WITH ANTI-A, ANTI-B, OR ANTI-H ANTISERA
• The treated saliva sample is mixed with a_______ ; 1 drop each
The antisera must be in____ dilution
• The antigen-antibody reaction is allowed to occur at room temperature for about____
specific antisera (e.g., anti-A, anti-B, or anti-H)
¼
10- 30 minutes.
PRCEDURE
STEP 4: ADDITION OF INDICATOR RBCS
• After incubation, group O RBCs with________ are added; 1 drop each
Reagent red cells: Must be in ____ suspension
• The mixture is centrifuged (15 seconds) and observed for agglutination.
STEP 5: GRADING
• Gently dislodge the cell button and observe for agglutination.
Grade and record results.
known A, B, or H antigens
5%
Blood Group (Secretor)
Tube A (Known A Cells + Anti-A)
Tube B (Known B Cells + Anti-B)
Tube H (Known H Cells + Anti-H)
Soluble Substance(s) Detected in Saliva
A
0
+
0
A, H
Blood Group (Secretor)
Tube A (Known A Cells + Anti-A)
Tube B (Known B Cells + Anti-B)
Tube H (Known H Cells + Anti-H)
Soluble Substance(s) Detected in Saliva
B
+
0
0
B,H
Blood Group (Secretor)
Tube A (Known A Cells + Anti-A)
Tube B (Known B Cells + Anti-B)
Tube H (Known H Cells + Anti-H)
Soluble Substance(s) Detected in Saliva
AB
0
0
0
A,B,H
Blood Group (Secretor)
Tube A (Known A Cells + Anti-A)
Tube B (Known B Cells + Anti-B)
Tube H (Known H Cells + Anti-H)
Soluble Substance(s) Detected in Saliva
O
+
+
0
H
______ is a positive result
______is a negative result
Absence of agglutination
Presence of agglutination
______is to prevent zonal reaction
Dilution of reagents and samples
Excessive levels of ABH substances leads to ABO discrepancies
Pseudomucinous ovarian cyst
Pancreatic and stomach carcinoma
Intestinal obstruction
