Purification of human PCs from different territories.

The figure shows a representative example of the consecutive steps followed in the protocol used for the purification of PCs from tonsil (CD20/CD38 staining, upper panel), blood (CD19/CD38 staining, middle panel), and BM (CD19/CD38 staining, lower panel). Tonsil CD38^h cells were pre-enriched by treatment with anti-CD31 mAb and MACS, and this cell fraction was the starting point in isolating tonsil CD38^h cells by FACS. PBMC from tet-immunized volunteers were used in a first step of blood CD38^h cell pre-enrichment by treatment with anti-CD19 mAb and MACS. Blood CD38^h cells were finally purified from this CD19⁺ cell fraction by FACS. BM CD38^h cells were isolated from BMMCs in a single step by treatment with anti-CD138 mAb and MACS. In the 3 territories CD38^h cells were identified as PCs by Giemsa staining as well as intracytoplasmic Ig staining of cytospin preparations of purified CD38^h cells (upper and lower photograph, respectively), in each territory. Original magnification × 300.