Rapid selection of donor myoblast clones for muscular dystrophy therapy using cell surface expression of NCAM

This study describes an easy 3 step-procedure to prepare rapidly and at low cost, pure myoblast cell cultures from a normal muscle biopsy. Following collagenase and trypsin treatment of the tissue (step 1), dissociated cells were cloned at a density of 10 cells/ml in MCDB 120 medium (0.2 ml/well). Clones that grew were then tested for NCAM cell surface expression by cytofluorometric analysis (CFA) using Coulter CD56-PE monoclonal antibodies (step 2). Only those clones with more than 98% strongly labelled positive cells were expanded (step 3) for further trials in cell transfer therapy for dystrophic patients. Visualization of the pattern of NCAM expression was performed by immunoperoxidase assay, while the potential ability to form myotubes was confirmed by the observation of their formation within a period of 1 to 2 weeks. The 65% of the CD56+ clones in CFA were the same clones that proved to be myogenic with positive immunoperoxidase assay and myotube formation. This method avoids the fastidious and costly approach of cell sorting (whenever available), avoids contamination hazards due to many manipulations of the clones. Moreover this approach leads to a pure myoblast population free of any contaminating fibroblast which could contribute to connective tissue implement already deleterious in dystrophic patients.