[11] CHAPTER V LESSON 1 Flashcards
AHG’s obtained from immunized nonhuman species bind to human globulins such as (?] either free in serum or attached to antigens on red blood cells (RBC’s).
IgG or complement
2 major types of blood group antibodies:
IgM
IgG
- bind to corresponding antigen
IgM
directly agglutinate RBCs suspended in saline
IgM
- “nonagglutinating” or “incomplete antibodies”
IgG
because their single monomer structure is too small to directly agglutinate sensitized RBCs
IgG
described the use of the antiglobulin test for the detection of weak and nonagglutinating Rh antibodies in serum.
Coombs, Mourant, and Race
described the use of AHG to detect in vivo sensitization of the RBCs of babies suffering from HDFN.
Coombs and coworkers
described the principle of the test
Moreschi
Kell blood group antibodies and assoc. antigen
Moreschi
Reported weeks after the Coombs had described the test
Moreschi
- RBCs has been sensitized by an antibody
Hemagglutination
Early AHG reagents were prepared using a (?) as the immunogen.
crude globulin fraction
demonstrated that the antibody activity that detected Rh o antibodies were associated with the anti-gamma globulin fraction in the reagent.
Coombs and Mourant
: Observed that different reaction patterns were obtained when dilutions of AHG were used to test cells sensitized with warm as compared to cold antibodies.
Dacie
published data showing that the reactivity of AHG to cells sensitized with warm antibodies resulted from anti-gamma globulin activity, whereas antinongamma globulin activity was responsible for the activity of cells sensitized by cold antibodies.
Dacie and coworkers
was shown to be beta globulin and had specificity for complement
nongamma globulin component
Later studies revealed that the complement activity was a result of
C3 and C4
can be used to detect RBCs sensitized with IgG alloantibodies, IgG autoantibodies, and complement components.
antiglobulin test
can occur either in vivo or in vitro:
Sensitization
is detected by a one stage procedure
In vivo sensitization
In vivo sensitization ex.
Direct antiglobulin test (DAT)
The use of AHG to detect [?] of RBCs is a two-stage technique
in vitro sensitization
In vitro sensitization ex.
Indirect antiglobulin test (IAT)