Abortive differentiation of splenic Tfh cells in <i>L. infantum</i>-infected rhesus macaques.

<p>(<b>A</b>) The relative transcript levels of <i>CXCR5</i>, <i>BCL6</i>, <i>PDCD1</i> and <i>IL21</i> in sorted splenic CD4 T cells were quantified by qPCR. Results are shown as fold change ± SEM over non-infected samples. (<b>B</b>) Representative density plots depicting the expression of CXCR5 and Bcl-6 (upper panels) or CXCR5 and PD-1 (lower panels) in splenic CD4 T cells during the course of infection. (<b>C</b>) Expression (mean ± SEM) of CXCR5, Bcl-6 and PD-1 among splenic CD4 T cells during the course of infection. (<b>D</b>) Percentage (mean ± SEM) of expression of the double positive CXCR5⁺Bcl-6⁺ or CXCR5⁺PD-1⁺ populations and the triple positive CXCR5⁺Bcl-6⁺PD-1⁺ population among splenic CD4 T cells. (<b>E</b>–<b>F</b>) Correlation between the frequency of CXCR5⁺Bcl-6⁺ splenic CD4 T cells and the frequency of CD21⁻CD27⁺CD45RA⁻ splenic B cells (E) or the serum levels of <i>L. infantum</i>-specific IgG (F). (A–D) Data obtained from 2–4 animals per time point. (E–F) Each dot represents an individual animal. Statistical analysis was performed by one-way ANOVA, followed by a Bonferroni's post-hoc test. The Spearman's rank test was used for correlations.