Comprehensive phenotypic analysis of the gut intra-epithelial lymphocyte compartment: perturbations induced by acute reovirus 1/L infection of the gastrointestinal tract

Abstract

Intestinal intra-epithelial lymphocytes (IELs) form a highly specialized lymphoid compartment. IELs consist primarily of T cells that are dispersed as single cells within the epithelial cell layer that surrounds the intestinal lumen. These lymphocytes along with lamina propria lymphocytes are considered to play an important role in the regulation of immune responses. IELs are heterogeneous with regard to phenotype, and they contain sub-populations with diverse functions. In our most recent study, we found that intra-duodenal inoculation of mice with reovirus serotype 1/strain Lang (reovirus 1/L) induced expression of both germinal center and T cell antigen and CD11c on IELs suggesting these cells to be the recently stimulated cells in gut mucosal tissue. We also demonstrated that IELs from these mice when cultured in vitro in the presence of reovirus 1/L-pulsed antigen-presenting cells generated reovirus 1/L-specific MHC-restricted CTL whose function was mediated utilizing perforin, Fas-FasL and TRAIL mechanisms. This present study provides a comprehensive analysis of the diverse subsets of IELs, which function with other mucosal cells to provide a strong, protective immunity in a highly regulated fashion inside the microenvironment of the intestinal epithelium. We demonstrated that the IEL population contains both thymus-dependent (TD) and thymus-independent (TI) lymphocytes in mice and that a complex phenotype is present when sub-populations are analyzed for TCR, Thy-1, CD4, CD8 and B220 expression in a comprehensive manner. In reovirus 1/L-inoculated mice, we found a decrease in the TI population and an increase in the TD population characterized by significant alterations in various sub-populations. This increase was largely due to an increase in CD4(+), CD8(+) and CD4/CD8 double-positive sub-populations of TD IELs. Intracellular cytokine analysis demonstrated induction of IFN-gamma and an increase in effector/cytotoxic CD8 and CD4 cells after reovirus 1/L infection. These results suggest that TD IELs may play an important role in the clearance of reovirus 1/L infection from gut.

Alteration of the Thymic T Cell Repertoire by Rotavirus Infection Is Associated with Delayed Type 1 Diabetes Development in Non-Obese Diabetic Mice

“…RRV infection had no effect on CD8 + TCRγδ IEL, which increased as a proportion of total T cells from 19±4% on day 14 post infection to 47±2% on day 21 and 59±1% on day 35 in both mock- and RRV-infected NOD mice (C. Zufferey and B. S. Coulson, unpublished data). These results confirm previous findings that the TCRγδ IEL frequency in mice reaches ∼50% by 20 days of age, and are consistent with the lack of effect of reovirus infection on TCRγδ IEL frequency compared to control mice [48], [49]. The low level of RRV replication in infant C57BL/6 mice may explain their unaltered numbers of CD8αβ TCRαβ IEL and rapid decrease in PD-L1 expression intestinally.…”

Salivary glands act as mucosal inductive sitesviathe formation of ectopic germinal centers after site‐restricted MCMV infection

“…Activated B cells express the GL7 epitope, but mature B cells do not; thus, GL7 serves as a marker for GCs in the immunized spleen and lymph nodes (60,61). Further, our results demonstrating GCT expression in ectopic GCs of the salivary gland and its coexpression on B220 ϩ B cells would suggest that these cells are recently activated MCMV-specific cells, since we have previously found a similar population of B220 ϩ GCT ϩ B cells in PPs after acute stimulation with reovirus (15)(16)(17)(62)(63)(64). In addition, our earlier studies demonstrated that GCT is a marker, which identifies reovirus 1/L-specific precursor and effector CTL in PPs of reovirus 1/Linoculated mice (17,63).…”

“…In addition, our earlier studies demonstrated that GCT is a marker, which identifies reovirus 1/L-specific precursor and effector CTL in PPs of reovirus 1/Linoculated mice (17,63). We demonstrated that GCT is expressed by recently activated gut lymphocytes and that this recently stimulated GCT-expressing population preferentially migrated to the intraepithelial compartment and lamina propria following enteric virus infection (16,17). These results suggested that GCT can be used as an activation marker for gut lymphocytes.…”

“…2D). GCT has been described as a GC B-cell marker and a marker for T lymphocytes that have recently egressed from a mucosal inductive site (15)(16)(17). GCT ϩ cells (blue) were detected within the salivary gland follicles ( Fig.…”

Prevention of TNBS-induced colitis by different Lactobacillus and Bifidobacterium strains is associated with an expansion of γδT and regulatory T cells of intestinal intraepithelial lymphocytes

“…[26][27][28] LPLs constitute the major effector cells along gut mucosal surfaces, whereas IELs are interspersed with enterocytes, thus having direct contact with foreign antigens derived from the gut lumen, and are thought to play a key role in the immune responses toward these antigens and in the pathogenesis of a variety of diseases. 29,30 A role in the repair from experimental colitis in mice has been ascribed to IELs due to the activity of cdT cells, [31][32][33] which represent a major T-cell subpopulation within IELs. 34 While some studies have indicated a regulation of LPLs function by probiotics in IBD, 35 up to now there are no data of a possible involvement of IELs in the protective activity of probiotics in colitis.…”