Pglyrp3/4 Promote Treg and Inhibit Th17 Responses Figure 5. Pglyrp3 and Pglyrp4 are expressed primarily in the differentiated epidermal cells in both untreated and oxazolone- treated skin in the atopic dermatitis model. Transverse sections of the ears from either untreated or oxazolone-treated mice (sensitization followed by 10 applications of oxazolone to the ears every other day) were stained by an immunoperoxidase method with either anti-Pglyrp3 or anti- Pglyrp4 antibodies or IgG (negative control); bar = 50 mm. doi:10.1371/journal.pone.0024961.g005 higher numbers of Th17 cells (CD4+IL-17+) in the affected ears in Pglyrp32/2 mice compared to WT mice (Figure 8A, B and C). Thus, on day 20 in Pglyrp32/2 mice the numbers of Th17 cells in the ears increased from undetectable (,10/ear) to ,650 Th17 cells/ear, 3.5 times higher than in WT mice (Figure 8A). Virtually all detectable IL-17+ cells in the oxazolone-treated ears were CD4+ (Th17 cells) and there were very few (,50/ear, not shown) other IL-17+ cells in the inflamed skin (such as CD8+, c/d T cells, or NKT cells), and therefore the observed increases in the numbers IL-17+ cells mostly represent increases in Th17 cells (CD4+IL-17+). There was no significant difference in the numbers of Th1 (CD4+IFN-c+) and Th2 (CD4+IL-4+) cells in the ears of WT and Pglyrp32/2 mice on day 20 (Figure 8C). Oxazolone-treated mice had substantially swollen cervical lymph nodes (.3 mm in diameter, compared to ,0.5 mm in untreated mice), where on day 13 the numbers of Th2 cells and on day 20 the numbers of all PLoS ONE | www.plosone.org 7 September 2011 | Volume 6 | Issue 9 | e24961