INDUCTION OF SURFACE-ANTIGEN RECOGNIZED BY NEW MONOCLONAL-ANTIBODY, YU311, ON 1-BETA-D-ARABINOFURANOSYLCYTOSINE-RESISTANT HUMAN LEUKEMIC-CELL LINE

A new monoclonal antibody, YU311, against an antigen expressed on 1-beta-D-arabinofuranosylcytosine(araC)-resistant human leukemic cell line with decreased deoxycytidine kinase activity was generated. YU311 reacted with ara-C-resistant human leukemic cell line (KY-Ra), but not with its parental cell line (KY-821) which was sensitive to ara-C. YU311 recognized the 92-kDa membrane protein. Furthermore, YU311 inhibited the growth of KY-Ra in suspension medium with and without ara-C. In immunocytochemistry, there was no difference in expression of usual differentiation antigens between KY-Ra and KY-821. These findings indicate that antigenic change could occur in ara-C-resistant human leukemic cells with stable expression of differentiation antigens and that the 92-kDa membrane protein may be one of the membrane proteins which regulate cell growth of KY-Ra.