Dominant trait linked to chromosome 1 in DBA/2 mice for the resistance to autoimmune gastritis appears in bone marrow cells

Rewiring of Microbiota Networks in Erosive Inflammation of the Stomach and Small Bowel

The development of non-invasive, inexpensive, and effective early diagnosis tests for gastric and small-bowel lesions is an urgent requirement. The introduction of magnetically guided capsule endoscopy (MGCE) has aided examination of the small bowel for diagnoses. However, the distribution of the fecal microbiome in abnormal erosions of the stomach and small bowel remains unclear. Herein, alternations in the fecal microbiome in three groups [normal, small-bowel inflammation, and chronic gastritis (CG)] were analyzed by metagenomics and our well-developed method [individual-specific edge-network analysis (iENA)]. In addition to the dominant microbiota identified by the conventional differential analysis, iENA could recognize novel network biomarkers of microbiome communities, such as the genus Bacteroide in CG and small-bowel inflammation. Combined with differential network analysis, the network-hub microbiota within rewired microbiota networks revealed high-ranked iENA microbiota markers, which were disease specific and had particular pathogenic functions. Our findings illuminate the components of the fecal microbiome and the importance of specific bacteria in CG and small-bowel erosions, and could be employed to develop preventive and non-invasive therapeutic strategies.

Induction of autoimmune gastritis by neonatal thymectomy requires autoantibodies and is prevented by anti-FcγR antibodies

The autoantibodies (auto-Abs) that are a hallmark of neonatally thymectomized (NTx) mice with autoimmune gastritis (AIG) have been poorly explored. We investigated their immune significance using B cell-deficient (B(-)) mice and found that B(-) mice are totally resistant to AIG but become susceptible to AIG after receiving bone marrow cells from B(+) mice. This susceptibility is most likely caused by the production of auto-Abs by B cells because B(-) pups also became susceptible to AIG when nourished by an AIG dam producing auto-Abs of the IgG class during the suckling period. NTx B(-) mice receiving purified IgG auto-Abs at this developmental stage similarly developed AIG. Auto-Abs probably act on antigen handling for antigen presentation because the treatment of NTx B(+) mice with anti-FcγR Abs prevented the development of AIG. Auto-Abs are indispensable for AIG development but are not sufficient because auto-Ab treatment did not increase AIG incidence in NTx B(+) mice above the baseline.

Population doublings of murine CD4(+) memory T cells during continuous antigen stimulation in vivo

We investigated the expansion rate of CD4(+) memory T cells using a newly developed in vivo system. Neonatal thymectomy abrogates the subsequent production of T cells and induces autoimmune gastritis (AIG) by the activation of CD4(+) T cells; this disease was transferred into athymic nude mice through the inoculation of splenic CD4(+) memory T cells. The transferred CD4(+) T cells increased logarithmically in number during the first 2months in the spleen of the recipients. The serial transfer of these splenocytes at two-month intervals revealed that the numbers of the AIG-transferable generations were inversely correlated with the age of the first AIG donors. The duration of the AIG-promoting capacity of CD4(+) T cells under continuous antigenic stimulation in vivo was approximately equivalent-one and a half years. These results indicate that there exists an intrinsic population doubling limit in memory CD4(+) T cells similar to that of self-renewing naïve ones.