Direct and indirect antibody-induced TX-100 resistance of cell surface antigens.

Translocation into detergent-insoluble microdomains (rafts) represents one of the earliest events in the process of cell activation, which follows the binding of surface receptor with natural ligand or mimicking antibody. In this study, the antibody-induced TX-100 resistance of surface antigens has been studied utilizing flow cytometry on TX-100 extracted cells. TX-100 resistance was evaluated by the ratio of antigen retained on the cells after detergent extraction compared with mAb-pretreated and untreated cells. All the antigens under study except CD98 demonstrated antibody-induced TX-100 resistance if the cells were treated with monoclonal antibodies and further cross-linked with secondary antibodies prior to lysis. CD20, CD5, and sIgM molecules were capable of transferring into TX-100-insoluble state in the absence of additional cross-linking. The experiments on modification of raft and cytoskeletal components of the cell, as well as the data on co-localization of TX-100-resistant antigens with raft and cytoskeletal markers strongly indicate that antibody-induced TX-100 resistance of antigens is mainly related to the translocation of antigens into lipid microdomains.