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. 2021 Feb 12;11:628923. doi: 10.3389/fimmu.2020.628923

Figure 5.

Figure 5

PD-1 is upregulated on IgA-expressing BMPC following BCR stimulation. BM MNCs were cultured for up to four days in the presence of 1 µg/ml anti-BCR F(ab)2 IgM/IgG/IgA (aBCR) or medium (control). (A) A representative histogram of PD-1 is shown (filled grey: staining d1 medium control; solid lines: staining d1 aBCR). PD-1 expression on IgA+ (left) and IgA− (right) BMPC was analyzed among the subsets defined by CD19. Mean ± SD; n = 6–16 for each timepoint, Kruskal-Wallis-Test with Dunn’s correction for multiple comparisons. *p < 0.001, **p < 0.0001. (B) Absolute cell counts of PD-1+ cells during the culture with anti-BCR among IgA+ (left) and IgA− (right) BMPC of CD19+ and CD19− BMPC. Mean ± SD; n = 5–12 for each timepoint, Kruskal-Wallis-Test with Dunn’s correction for multiple comparisons. *p < 0.001. (C) PD-1 expression on IgM+ BMPC was analyzed among the subsets defined by CD19. Mean ± SD; n = 4–9 for each timepoint, Kruskal-Wallis-Test with Dunn’s correction for multiple comparisons. (D) Representative histogram (d1 medium control and aBCR) of BTLA (MFI) and cumulative data of IgA+ and IgA− CD19+/− BMPC after BCR stimulation. n = 2–16 for each timepoint. (E) BM MNCs were incubated with SYK inhibitor entospletinib or DMSO as a control 30 min prior to stimulation with anti-BCR for 1 day and stained for PD-1 together with CD19, IgA and IgM. Frequency of PD-1+ cells from stimulated samples minus unstimulated controls (Δ%) for the BMPC subsets defined by CD19, IgA and IgM, bar indicates mean, n = 3.