IMMUNOLOCALIZATION OF CYCLOPHILIN IN NORMAL AND CYCLOSPORINE A-TREATED HUMAN-LYMPHOCYTES

A polyclonal rabbit antibody against a protein fraction (10-30 kDa) of human thymuses with a high CsA-binding activity of dominant protein c yclophilin (CPH) was prepared and characterized. In immunoblotting wit h the cell lysate from JURKAT T cell line, this antibody specifically reacted with 18-kDa protein corresponding to CPH. In indirect immunofl uorescence the antibody visualized granular structures in JURKAT cells and human peripheral blood lymphocytes. In JURKAT cells cultivated wi th 1-2 mu g of CsA per ml for 7 days a much weaker reaction of the ant ibody was found, compared with non-treated cells. In some CsA-treated cells the antibody visualized various 'star-like' or filamentous struc tures. A similar staining pattern has also been obtained in lymphocyte s of the patients receiving CsA therapy. Complementary staining with r hodamine-tagged phalloidin revealed changes in F-actin distribution of CsA-treated JURKAT cells. In conclusion, the treatment with CsA induc es dramatic changes of CPH cellular distribution, which may take part in the final therapeutic effect of the drug.