Figure 4. Two-color flow cytometric (A) and immunohistochemical (B-D) analyses of CD13⁺CD3⁺ cells that had infiltrated the gingival tissues of periodontitis patients. (A) Single-cell suspensions from gingival tissues and peripheral blood mononuclear cells of 10 periodontitis patients were stained with FITC-conjugated UCHT-1 (anti-CD3) and/or biotin-conjugated 22A5 (anti-CD13) followed by PE-conjugated SAv, and then subjected to flow cytometric analysis. Results are shown as Mean ± SD of percentage of CD13⁺CD3⁺/CD3⁺ cells in each sample. *Significantly different between gingival tissues and peripheral blood (p < 0.01 by Student’s t test). (B-D) Sections of gingival tissues from periodontitis patients were analyzed by immunohistochemistry as described in MATERIALS & METHODS. Sections were stained with FITC-conjugated UCHT-1 (anti-CD3) (B) and biotin-conjugated 22A5 (anti-CD13) followed by PE-conjugated SAv (C). The combined image of panels (B) and (C) is shown in panel (D). CD13⁺CD3⁺ cells are arrowed.