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. 2011 Nov 10;6(11):e27528. doi: 10.1371/journal.pone.0027528

Figure 5. Increased IL-7 production and expansion of fibroblastic reticular cells in LNs of old MRL-Faslpr mice.

Figure 5

(A) Transcript level analysis. RT-PCR was performed to examine IL-7 and IL-7Rα expression in LNs of young (Y, 6 weeks) and older (O, 20 weeks) MRL-Faslpr and control C57BL/6 (B6) mice. Data were normalized using HPRT1 and expressed as fold change (± SD) compared to transcript levels in B6 mice. (B) IL-7 protein levels in young and older MRL-Faslpr. Immunoblot was used to determine IL-7 protein levels in LNs of young (Y, 6 weeks) and older (O, 18 weeks) MRL-Faslpr and control C57BL/6 (B6) mice. Data acquired by densitometry were normalized using β-actin and expressed as ford change (± SD) compared to IL-7 protein levels in B6 mice. (C) Flow cytometric analysis of fibroblastic reticular cells (FRCs). LN cells of MRL-Faslpr and control B6 mice were stained with antibodies to CD45, gp38 (podoplanin) and CD31. Representative plots showing the frequency of FRCs (CD31– gp38+) in the CD45– LN cell population are depicted. (D) Accumulation of FRCs and IL-7Rα+ T cells in MRL-Faslpr mice. The number (± SD) of FRCs and IL-7Rα+ T cells in LNs of young and older MRL-Faslpr compared to B6 controls was determined by flow cytometry. (E) Accumulation of FRCs is proportional to the number of total LN cells in MRL-Faslpr mice. LN cells were isolated from mice displaying various levels of lymphadenopathy. The numbers of FRCs (CD45– CD31– gp38+) and IL-7Rα+ T cells (TCRβ+) were determined by flow cytometry and plotted as a function of the number of total LN cells for each individual mouse. Linear regression and goodness of fit (r) were calculated using Prism 4 software. Dotted lines indicate the frequency ± 1 STD of FRCs (left panel) and IL-7Rα+ T cells (right panel) as determined in young mice before development of lymphadenopathy, and predict how these cell types would accumulate with disease progression if their frequencies were maintained at a constant. Data are representative of 2–3 independent experiments with 3–5 mice/group. Asterisks indicate statistical significance (p<0.05).