Tfh cells are associated with autoantibody production in MRL/lpr mice.

<p>(<b>A</b>) H&E staining of spleens from MRL/lpr and B6 mice (left). PNA⁺ GC cells were determined by immunohistochemical staining (right). The scale bar represents 50 μm. (<b>B</b>) A positive correlation between the percentages of CD4⁺CXCR5⁺PD-1⁺ T cells and the number of PNA⁺ GC cells in spleens of MRL/lpr mice (n = 6) was observed. (<b>C</b>) A positive correlation between the percentages of CD4⁺CXCR5⁺PD-1⁺ T cells and renal scores of MRL/lpr mice (n = 6) was observed. (<b>D</b>) A positive correlation between serum levels of IL-21 and ANA in MRL/lpr mice (n = 6) was found. (<b>E</b>) A positive correlation between serum levels of IL-21 and ds-DNA in MRL/lpr mice (n = 6) was found. (<b>F</b>) Sorted CD4⁺CXCR5⁺PD-1⁺ Tfh cells from MRL/lpr and B6 mice were cultured in the presence of anti-CD3 and anti-CD28 for 2 days, detection of IL-21 in the supernatants by ELISA. Results shown are representative of at least three independent experiments. (<b>G</b>) The concentrations of IgM and IgG₁ in sorted naive B cells from B6 mice following a 3-day induction with LPS, anti-CD40, anti-IgM, and 20% of the supernatants from cultured Tfh cells from MRL/lpr (mTfh) and B6 mice (bTfh) or vehicle (culture media with 2 µg/ml plate-bound anti-CD3 and 2 µg/ml soluble anti-CD28) with or without neutralization of IL-21. Results shown are representative of at least three independent experiments.