A trial of alloreactive T-cell depletion using biotinylated galactose oxidase for the prevention of acute graft-versus-host diseases.

: Galactose oxidase was labelled onto the surface of mitomycin-C treated splenic lymphocytes from BALB/C mice (H-2d, Mlsb). Mouse splenic lymphocytes from DBA/2 (H-2d, Mlsa) mixed with the galactose oxidase labelled BALB/C lymphocytes allowed DBA/2 cells which recognized the Mlsb on the BALB/C cells to make direct contact with the galactose oxidase labelled BALB/C cells. By adding galactose, sodium iodide and catalase to the mixture, the contacting stimulator cells will generate hydrogen peroxide in the vicinity of the contacting responder cells and the iodine ions will exert a toxic effect on the responder cells while non-specific cytotoxicity was prevented by catalase. When fresh mitomycin-C treated BALB/C lymphocytes were added to the cell mixture, the mixed lymphocyte response against BALB/C cells by the treated DBA/2 lymphocytes was abolished. On the other hand, when fresh mitomycin-C treated lymphocytes from C57BL/6 mice (H-2b, Mlsb) were mixed with the treated DBA/2 cells, the mixed lymphocyte response against C57BL/6 cells by the treated DBA/2 lymphocytes was partially retained. Therefore, although some non-specific cytotoxicity was present, a method to deplete specific T-lymphocytes that recognize major histocompatibility antigen from a mixed cell population while maintaining immune responsiveness towards other antigens was developed. This method may have a beneficial effect on the control of post-transplant immunity and may be used as a prophylaxis of graft-versus-host disease.