Fig. 1.

B cells induce peripheral tolerance in antigen-specific and polyclonal T-cell populations. (A–C) Naive, LPS or CpG WT (open symbols) or mOVA B cells (filled symbols) (10⁷) were transferred into WT C57BL/6 mice. Two weeks after OVA challenge, T cells from peripheral lymph nodes were cultured in vitro in the presence of the indicated concentrations of pOVA 323–339, and the rate of proliferation was determined by [³H] thymidine incorporation (mean Δcpm ± SE, n = 3). (A) T-cell proliferation in cells recovered from animals receiving unstimulated WT or mOVA B cells (n = 3; P < 0.03 for >3 μM OVA). (B) T-cell proliferation in cells recovered from animals receiving LPS-treated WT or mOVA B cells (n = 3; P ≤ 0.02 at all concentrations). (C) T-cell proliferation in cells recovered from animals receiving CpG-treated WT or mOVA B cells (n = 3; P values not significantly different). (D–F) Serum and whole-splenocyte cell cultures from the same animals were used to assess anti-OVA IgG titers and IFN-γ production measured by ELISpot (mean background − subtracted spots ± SE). (D) IgG titers after transfer of WT or mOVA B cells (n = 3; unstimulated B cells, P = 0.02; LPS B cells, P = 0.001; CpG B cells P values not significantly different). (E) IFN-γ production after transfer of LPS-treated WT or LPS mOVA B cells and peptide rechallenge (n = 3; P = 0.03 for 2 μM OVA; P = 0.06 for 6 μM OVA). (F) IFN-γ production after transfer of CpG-treated WT or CpG mOVA B cells and peptide rechallenge (n = 4; P values not significantly different). (G and H) LPS- or CpG mOVA B cells were transferred into a WT mouse 1 d before OTII T cells. Seven days after OTII T-cell transfer, T-cell proliferation from pooled peripheral lymph nodes and spleen was assessed. (G) T-cell proliferation in cells recovered from animals receiving LPS-treated WT or mOVA B cells (n = 3; P < 0.01). (H) T-cell proliferation in cells recovered from animals receiving CpG-treated WT or mOVA B cells (n = 4; P = no significant difference).