Production of a Recombinant Antibody Specific for i Blood Group Antigen, a Mesenchymal Stem Cell Marker

Abstract Multipotent mesenchymal stem/stromal cells (MSCs) offer great promise for future regenerative and anti-inflammatory therapies. Panels of functional and phenotypical markers are currently used in characterization of different therapeutic stem cell populations from various sources. The i antigen (linear poly- N-acetyllactosamine) from the Ii blood group system has been suggested as a marker for MSCs derived from umbilical cordblood (UCB). However, there are currently no commercially available antibodies recognizing the i antigen. In the present study, we describe the use of antibody phage displaytechnology to produce recombinant antibodiesrecognizing a structure from the surface of mesenchymal stem cells. We constructed IgM phage displaylibraries from the lymphocytes of a donor with an elevated serum anti-i titer. Antibody phage displaytechnology is not dependent on immunization and thus allows the generation of antibodies against poorly immunogenic molecules, such as carbohydrates. Agglutinati...