Rapid detection of JMH antibodies with recombinant Sema7A (CD108) protein and the particle gel immunoassay.
BACKGROUND
At present, identification of antibodies against the high-prevalence JMH antigen is difficult and limited to reference laboratories having panels of rare red blood cell (RBC) specimens in stock. Here, a novel method is described for detection of anti-JMH with particles coated with recombinant semaphorin 7A (Sema7A, CD108), the protein that carries the JMH blood group antigens.


METHODS
Recombinant Sema7A protein was generated and coupled onto superparamagnetic particles coated with streptavidin. The coated particles were tested in the presence of different serum and plasma samples (11 anti-JMH, 20 other antibodies, and 50 samples from nonimmunized blood donors) with the particle gel immunoassay and flow cytometry.


RESULTS
Sema7A-coated particles reacted with all 11 samples containing anti-JMH, but not with samples lacking anti-JMH. In addition, the anti-JMH agglutination scores were higher with Sema7A-coated particles than with JMH-positive RBCs in all cases.


CONCLUSIONS
Recombinant blood group proteins have the potential to replace RBCs as antigen carriers for identification of certain RBC alloantibodies.
Seltsam
Axel
A
Institute for Transfusion Medicine, Hannover Medical School, Hannover, Germany. seltsam.axel@mh-hannover.de
Agaylan
Ashraf
A
Grueger
Daniela
D
Meyer
Oliver
O
Blasczyk
Rainer
R
Salama
Abdulgabar
A
D015703:Antigens, CD / Q000276:immunology*; D001789:Blood Group Antigens / Q000276:immunology*; D002460:Cell Line; D058851:GPI-Linked Proteins; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007518:Isoantibodies / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology; D039961:Semaphorins / Q000276:immunology*; D012995:Solubility; D013997:Time Factors
D015703:Antigens, CD; D001789:Blood Group Antigens; D058851:GPI-Linked Proteins; D007518:Isoantibodies; D011994:Recombinant Proteins; C118753:SEMA7A protein, human; D039961:Semaphorins