Figure 6.

Detection of GMRα on the surface of blood leukocytes. Cell surface expression of mouse GMRα in different blood cell populations was determined by FACS using GM-Fc or control-Fc. (A) Granulocytes were gated by their SSC^highFSC^int–high phenotype (left panel 1), and subdivided into neutrophils (Neu, Gr-1^highSSC^high; left panel 2), eosinophils (Eos, Gr-1^lowSSC^v.high; left panel 2) and basophils (Bas, CD49b⁺IgE⁺; left panel 3). Binding of control-Fc (middle panels) and GM-Fc (right panels) was then assessed on the three populations as indicated. GM-Fc bound to all three granulocyte populations (B) Monocytes (Mo) were identified by their F4/80⁺CD11b⁺ phenotype (left panel) after gating on SSC^low cells (not shown). The monocytes were further divided by their expression of Gr-1 and assessed for binding of control-Fc (middle panel) or GM-Fc (right panel). GM-Fc bound well to both major monocyte subsets. (C) GMRα expression was also determined on lymphoid cells. T cells (top panels, gated on CD3⁺), NK cells (middle panels, gated on CD3^–CD49b⁺) and B cells (bottom panels, gated on CD19⁺) were assessed for binding of GM-Fc (grey lines) and control-Fc (black line). No specific binding of GM-Fc was detected on the lymphocyte populations.