Naive, memory, and GC B cells within secondary lymphoid tissue differ in their CCR6 expression.

(A) CCR6 expression was studied within PBMC populations by 2-parameter immunofluorescence analysis using PE-labeled CCR6 MoAb and FITC-labeled CD19 or CD3 MoAbs. (B) Freshly isolated tonsillar B cells were separated according to the expression of distinctive immunophenotypic markers into sIgD^high (naive), sIgD⁻CD44^high (memory), and sIgD⁻CD44⁻ GC B cells, as described in “Material and methods.” CCR6 expression was then assessed by FACS analysis using anti-CCR6-PE MoAb. MFI values for CCR6 staining for individual samples are indicated. Open histograms represent staining with IgG₁ control MoAb. One representative donor of 4 is shown.