Hemagglutination inhibition of Cromer blood group antibodies with soluble recombinant decay-accelerating factor.
BACKGROUND
Cromer blood group antigens are located on decay-accelerating factor (DAF, CD55), which contains four short consensus repeats (SCRs). Cromer system antibodies may be of clinical significance in blood transfusion.


METHODS
Soluble recombinant DAF (srDAF) constructs, consisting of all four SCRs or of only two SCRs, were expressed in the yeast Pichia pastoris. They are used in hemagglutination-inhibition tests with Cromer system antibodies and with DAF-specific monoclonal antibodies.


RESULTS
The srDAF inhibited hemagglutination by all Cromer system alloantibodies in undiluted serum. Antibodies to antigens of other blood group systems were not inhibited by the srDAF. Hemagglutination-inhibition tests with domain-deleted srDAF showed that UMC is on SCR-4 and confirmed that Tca, TcaTcb, and WESb are on SCR-1; Dra is on SCR-3; and Cra is on SCR-4.


CONCLUSIONS
Hemagglutination inhibition with srDAF is useful in the recognition of antibodies that belong to the Cromer blood group system and facilitates pretransfusion testing. This use of domain-deleted srDAF provides an easy method of determining epitope location on DAF and is an aid to more precise identification of Cromer system antibodies.
Daniels
G L
GL
Bristol Institute for Transfusion Sciences, United Kingdom.
Green
C A
CA
Powell
R M
RM
Ward
T
T
D001789:Blood Group Antigens / Q000276:immunology*; D018958:CD55 Antigens / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*; D006385:Hemagglutination Inhibition Tests / Q000379:methods*; D006801:Humans; D007518:Isoantibodies / Q000097:blood; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology; D012995:Solubility
D001789:Blood Group Antigens; D018958:CD55 Antigens; D007518:Isoantibodies; D011994:Recombinant Proteins