The use of the 33CELLection Kit (TM) in the isolation of carcinoma cells from mononuclear cell suspensions

A study was performed to evaluate in vitro the sensitivity, specificity and variability of a new immunomagnetic microbead isolation technique which pr ovides subsequent immunological staining of captured carcinoma cells. In a mixture of peripheral blood mononuclear cells (PBMCs) and human carcinoma c ells the epithelial cancer cells were isolated with the Dynal(R) RAM IgG1 C ELLection(TM) Kit using Dynabeads M-280 coated with a rat monoclonal antibo dy (Mab) against mouse IgG1. The rat Mab was biotinylated and attached to D ynabeads via streptavidin and a DNA linker. The anti-epithelial monoclonal mouse antibody Ber-EP4 was used as the primary capture antibody. In order t o permit phenotyping of the isolated carcinoma cells the magnetic beads wer e removed from the carcinoma cells by DN'ase digestion of the DNA linker be tween the magnetic bead and the secondary antibody. In an ex vivo model sys tem an average recovery of approximately 60% of a human colon carcinoma cel l line HCC-2998 seeded in 5.10(6) PBMCs was obtained, and the recovered cel ls could subsequently be immunologically stained for the surface antigen CD 87 (urokinase plasminogen activator receptor). No positive stained cells we re found in control experiments with PBMCs without carcinoma cells. Despite a relatively low recovery, the described method will be valuable for the d etection of carcinoma cells in cytospin preparations with subsequent phenot yping of the cells for expression of surface antigens. Depending on the cho sen antibodies, the method may be useful for the isolation and characterisa tion of other cell types in various cell suspensions. (C) 2000 Elsevier Sci ence B.V. All rights reserved.