Positive immunoselection using antibody-enzyme complexes.

We have developed an immunoselection technique using catalase-anti-catalase complexes coupled to specific antibodies to protect antigen positive target cells from the lethal effects of H2O2. The antibody-enzyme complexes are bound to the target cells through an antibody bridge with specificity for both the complexes and an anti-target cell antibody. In a model system, Thy-1 positive (RL male 1-3) cells were protected by incubation with rabbit anti-brain-associated theta antigen (BAT), sheep anti-rabbit IgG [F(ab)'2] and catalase-anti-catalase complexes. The amount and composition of the complexes adhering to the cells were measured by dual radiolabeling of the catalase and anti-catalase immunoglobulin. This technique provides a means of identifying and isolating large numbers of cells bearing any antigen for which specific antisera are available.