Flow cytometric detection and phenotype of IRTA1⁺ cells. A tonsil total cell suspension was labeled with a control antibody (gray histogram) and IRTA1 or lineage-specific markers (black lines). (Left) IRTA1⁺ cells (5.5% in this sample) are gated. (Right) Top row shows total and purified B-cell phenotype; bottom row, IRTA1⁺ cell gating. All staining was performed with the anti-IRTA1 polyclonal antibody.