Figure 6. Transferred residual γδ T cells alter splenic B cells in vivo and co-cultured residual γδ T cells selectively diminish MZ B cells in vitro.

(A) B6.TCR-δ^−/− mice (δ^−/−) were transferred with purified splenic γδ T cells from B6.TCR-Vγ4^−/−/Vγ6^−/− (Vγ4^−/−/6^−/−) or B6.TCR-Vγ4^−/−/Vγ6^−/−/IL-4^−/− (Vγ4^−/−/6^−/−/IL-4^−/−) mice. 10 days after the cell transfer, B cell populations in the spleen were compared as detailed for Figure 2, using the indicated markers. Data of one representative experiment are shown. (B) Effect of transferred residual γδ T cells on absolute numbers of MZB cells in the spleen of δ^−/− mice, n = 4 mice per group. (C) Effect of transferred residual γδ T cells on CD21 expression in the spleen of δ^−/− mice, n = 4 mice per group. (D) CD21 expression by transitional B cells in untreated wt, Vγ4^−/−/6^−/− and Vγ4^−/−/6^−/−/IL-4^−/−, n = 4 mice per group. *P<0.05, **P<0.01, ***P<0.001 (E) The CD8^pos fraction of Vγ1^pos γδ T cells in the spleen: Relative frequencies of CD8^pos γδ T cells within the splenic Vγ1^pos subset of C57BL/6 (wt), B6.TCR-Vγ4^−/−/6^−/− (Vγ4^−/−/6^−/−) and B6.TCR-Vγ4^−/−/Vγ6^−/−/IL-4^−/− (Vγ4^−/−/6^−/−/IL-4^−/−) mice. n = 5 mice per group, **P<0.01, ***P<0.001 (F) CD43-negative MZ B cell-rich splenic B cells from B6-TCR-Vγ1^−/− (Vγ1^−/−) mice were cultured for 60 hrs alone or in the presence of splenic Vγ1^pos γδ T cells from different mouse strains, and subsequently stained to identify MZ B cells. Only Vγ1^pos cells from B6.TCR-Vγ4^−/−/Vγ6^−/− (Vγ4^−/−/6^−/−) mice substantially diminished MZ B cells. (G) Same B cells as in panel a were cultured alone or in the presence of CD8^pos or CD8^neg fractions of Vγ1^pos cells from Vγ4^−/−/6^−/− mice, and subsequently stained to identify MZ B cells. Only Vγ1^pos cells expressing CD8 diminished MZ B cells. Data panels F and G are representative of several similar experiments.