Modulation of CALLA (CD10) antigen on cultured ALL (REH) cells: effect of various modulators.

Phorbol ester (TPA)-induced down-regulation of the common ALL (CALLA) antigen was studied by continuous flow immunocytometry with the aid of several CD10 monoclonal antibodies, including a new CD10 monoclonal antibody (DGH-10-1-A9), shown to be of IgG1 isotype, recognizing a 100 kDa cell surface protein and effectively inhibited by a series of reference CD10 monoclonal antibodies. The TPA-induced down-regulation of CALLA on REH cells was demonstrated with the aid of the following CD10 monoclonal antibodies: J-5, VIL-A1 and DGH-10-1-A9. No major modulations in cell surface expression of CALLA on REH cells were observed after induction with 1,25-(OH)2 vitamin D3, retinoic acid, recombinant interferon (IFN) alpha 2a and recombinant interleukin 2.