Characterization of anti–Ly-6M antisera.

(A) Stable K562 clones expressing either empty vector or the full-length Ly-6M cDNA (clones 1, 15, 25) were stained with control IgG (empty histograms) or anti–Ly-6M antisera (filled histograms). The antisera recognize a range of surface Ly-6M protein expression. (B) Stable K562 clones transfected with either the Ly-6A (upper plots) or Ly-6G (lower plots) cDNAs were obtained. On the left, transgene expression is demonstrated by staining with the indicated monoclonal antibodies (filled histograms) compared with isotype controls (empty histograms). On the right, no cross-reactive staining is noted when these same clones were analyzed using anti–Ly-6M antisera (filled histograms). (C, upper plot) A stable Ly-6M K562 clone was stained with control IgG (solid line) or anti–Ly-6M antisera (filled histogram). The GPI linkage of Ly-6M is demonstrated by a shift in fluorescence to the left when anti–Ly-6M staining was preceded by PI-PLC treatment (heavy line). (Lower plot) A stable Ly-6M K562 clone was stained with control IgG (solid line) or anti–Ly-6M antisera (filled histogram). The specificity of the antisera is demonstrated by a reduction in signal when anti–Ly-6M staining was preceded by preincubation with recombinant Ly-6M protein (heavy line).