Journal: PLoS ONE
Article Title: PP4 Is Essential for Germinal Center Formation and Class Switch Recombination in Mice
doi: 10.1371/journal.pone.0107505
Figure Lengend Snippet: ( A ) FACS assay of apoptosis of splenic B cells that were freshly isolated from WT and CD23 cre PP4 F/F mice (n = 3/group) and subjected to AnnexinV vs 7AAD staining. Viabilities are shown for the immature (IM), follicular (FO) and marginal zone (MZ) B cell populations. Numbers in quadrants represent the percentage of the indicated population relative to the total. ( B ) Quantitation of the percentage of viable (AnnexinV − 7AAD − ) cells in the IM, FO and MZ B cell populations in (A). Data are the mean ± SD of triplicate samples from each group. For (A–B), results are representative of two independent experiments. ( C ) In vivo BrdU incorporation assay. Left panel: WT and CD23 cre PP4 F/F mice (n = 3/group) were i.p. injected with BrdU twice daily (8 h apart) on 3 consecutive days. IM, FO and MZ splenocytes were freshly sorted, subjected to intracellular staining with anti-BrdU plus 7AAD, and analyzed by FACS. Right panel: Diagram indicating relative position of specific mitotic phase cells in the FACS profiles in the left panel. ( D ) Quantitation of the results in (C) showing the percentages of cells in the G0/G1, S and G2/M phases. Data are the mean ± SD of triplicate samples from each group. For (C–D), results are representative of two independent experiments. ( E ) In vitro BrdU incorporation assay. Splenic B cells were freshly isolated from WT (n = 3) or CD23 cre PP4 F/F (n = 4) mice and cultured in BrdU-containing maintenance medium alone (Medium), or in maintenance medium containing 1 µg/ml anti-IgM (IgM low), 10 µg/ml anti-IgM (IgM high), 5 µg/ml anti-CD40 Ab (CD40), 1 µg/ml anti-IgM plus anti-CD40 Abs (IgM/CD40), 1 µg/ml LPS (LPS low), or 10 µg/ml LPS (LPS high). After 48 h, cells were analyzed by FACS. Data shown are the quantitation of the mean percentage ± SD of B cells in S phase relative to total B cells after 48 h stimulation. ( F ) Quantitation of the mean percentage ± SD of B cells in G2/M phase from the data in (E) after 48 h stimulation. ( G ) Quantitation of the mean percentage ± SD of activated (CD80 + CD86 + ) B cells from the data in (E) after 24 h (d1) or 48 h (d2) of stimulation. ( H ) Quantitation of the mean percentage ± SD of CD40 + CD25 + B cells from the data in (G) after 48 h (d2) stimulation. For (E–H), results are representative of two independent experiments.
Article Snippet: Purified splenic B cells were seeded at a density of 1×10 6 /ml and cultured for 4 days in RPMI medium containing either 50 μg/ml lipopolysaccharide (LPS; InvivoGen) to induce switching from IgM to IgG 3 , or in RPMI medium containing 50 μg/ml LPS plus 10 ng/ml IL-4 (PeproTech) to induce switching from IgM to IgG 1 .
Techniques: Isolation, Staining, Quantitation Assay, In Vivo, BrdU Incorporation Assay, Injection, In Vitro, Cell Culture