Production and characterization of anti-Kell monoclonal antibodies using transfected cells as the immunogen

Monoclonal antibodies (Mabs) to blood group antigens are valuable as diagno stic reagents for typing red blood cells (RBCs) in the clinical setting, an d for structure-function studies of proteins, Here, we report a powerful sy stem that enabled us to produce Mabs to blood group antigens. A murine eryt hroleukaemia (MEL) cell line expressing Kell protein, a transmembrane glyco protein that carries a number of clinically relevant antigens, was used as a novel immunogen. Mabs with different specificities to the Kell protein we re produced from a single mouse fusion: an anti-js(b) (MIMA-8), and two ant ibodies (MIMA-9 and MIMA-10) with novel specificities, that reacted with RB Cs with the common Kell phenotype but not with RBCs with K+k- or Kp(a+b-) o r K-0 phenotypes, The non-reactivity with both K+k- or Kp(a+b-) RBCs implie d that the epitope was influenced by the molecular changes associated with an absence of the it or Kp(b) antigens. MIMA-8 is the first example of a Ma b anti-js(b) and was used in the clinical laboratory for screening donor RB Cs for Js(b-) blood and for typing RBCs from patients even when the RBCs we re coated with anti-IgG as is the case in autoimmune haemolytic anaemia. He avy and light chain variable regions of MIMA-8 were cloned and the sequence is given, This study illustrates the potential of this novel immunization approach for malting monoclonal antibodies to blood group antigens.