A High-Incidence Model for Autoimmune Gastritis Figure 4. Mice with autoimmune gastritis have an increased level of Foxp3+ Treg cells in the stomach. Cells were harvested from (A, B) paragastric lymph node, inguinal lymph node and (A, C) stomach tissue for intracellular staining of Foxp3. The numbers indicate the percentages of Foxp3+ Treg cells in donor CD90.2+CD4+ T cells in paragastric and inguinal lymph nodes and Foxp3+ Treg cells in total CD4+ T cells in stomach tissue. Data pooled from three independent experiments. In (B) and (C), each circle represents the data from one mouse. Mann-Whitney U test was used; bars, mean, and **, P,0.01. doi:10.1371/journal.pone.0027153.g004 the lack of T cell tolerance to the gastric autoantigen, which indicated the presence of H+/K+ ATPase-specific T cells in H/ Ka2/2 mice. We further demonstrated that transfer of CD4+ T cell populations from H/Ka2/2 mice induced damage to the stomach tissues of recipient mice soon after transfer. Autoimmune gastritis induced by the transfer of H/Ka2/2 CD4+ T cells was consistently severe: all the recipient mice developed the most severe disease eight weeks after transfer and their stomach physiology was significantly affected as indicated by the increase in stomach weight and pH. This model is advantageous because the severity and incidence of disease approaches that observed in TCR transgenic mice yet is caused by a polyclonal repertoire, it is technically simple to establish, it does not rely upon perturbation of the normal Treg cell repertoire. The donor cell population from the H/Ka2/2 mice was enriched to ,85% CD4+ T cells by a ‘‘negative selection’’ procedure because the major aim of this work was to produce a simple, inexpensive and convenient disease model. We conclude that it is the CD4+ T cells in the inoculum that caused Figure 5. Severity of autoimmune gastritis correlates to stomach weight. Mice were killed at indicated time points after transfer of CD4+ T cells from H/Ka2/2 mice and the severity of autoimmune gastritis was determined. Data were pooled from six independent experiments. Each circle represents the data from one mouse. Bars, mean. doi:10.1371/journal.pone.0027153.g005 Figure 6. Significant difference in stomach weight among gastritis scores. Thymectomy was performed on BALB.B6-Gasa congenic mice on day 3 of age and mice killed at 12 weeks. The severity of autoimmune gastritis and stomach weight was determined. Data pooled from at least 100 independent thymectomies. Each circle represents the data from one mouse. Mann-Whitney U test was used; bars, mean, **, P,0.01 and ***, P,0.001. doi:10.1371/journal.pone.0027153.g006 PLoS ONE | www.plosone.org 5 November 2011 | Volume 6 | Issue 11 | e27153