Bone Marrow Mesenchymal Stem Cells Enhance the Differentiation of Human Switched Memory B Lymphocytes into Plasma Cells in Serum-Free Medium

Figure 4

Mesenchymal stem cells influence plasma cell formation with or without cellular contact. Five independent samples of switched memory B lymphocytes were cultured as described in Figure 2(a) for the expansion and transition phases. For the differentiation phase, cells were grown in the presence of L4.5 cells, with or without MSC, which were added either in direct contact or in the upper chambers of a transwell. All assays were done in parallel for all conditions and at 21% and 8% O₂. The same gating strategy was used as described in Figure 3. (a) and (b) Frequencies of CD38⁺CD138⁺ populations as observed following culture at 21% and 8% O₂, respectively. (c) and (d) Frequencies of CD31⁺CD39⁺ populations as observed following culture at 21% and 8% O₂, respectively. (e) A representative profile of CD38 and CD138 expression at the end of the differentiation step for each condition tested at 21% O₂ is shown. (f) CD138 expression on cells following cultures with MSC in transwell (red line) and in direct contact (gray line), compared to unlabeled cells (shaded). Statistical analyses were done using a Dunn multiple comparison -test, and values are shown as indicated; , , and . Data are presented as means ± SEM.

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