Using positive selection one specific antibody binds directly to the celltype of interest. The cells will be “touched” by the antibody. All the unwanted cells remain unbound and will be separated from the labeled and wanted cells in the following enrichment steps. The easiest way to hold back the labeled cells, when coupled to a solid phase, is to use cell strainer or magnets.
The flow through is free of antibody-bound beads and can be used for another positive or negative cell enrichment. The enrichment with pluriBead can be done without any preparation of whole blood. The contamination with unbound cells especially platelets or erythrocytes is very low when the cells are directly isolated out of whole blood. Positive separation goes faster, is mostly less expansive and results in a higher purity