Details for: CL0000915

Cell ID: CL0000915

Cell Name: CD8-alpha-alpha-positive, alpha-beta intraepithelial T cell

Description: An alpha-beta intraepithelial T cell with the phenotype CD8-alpha-alpha-positive located in the columnar epithelium of the gastrointestinal tract. These cells have a memory phenotype of CD2-negative and CD5-negative.

Synonyms: CD8-alpha-alpha-positive, alpha-beta intraepithelial T lymphocyte, CD8-alpha-alpha-positive, alpha-beta intraepithelial T-cell, CD8-alpha-alpha-positive, alpha-beta intraepithelial T-lymphocyte

Selected Context(s): Overall

Gene Significance Landscape

Display Options
Score:
Display
Genes

Contexts:

Cell Significance Index (CSI) is uniquely calculated to reveal cell-specific gene markers. More info here

Significant Genes List

Genes with the highest and lowest Percentile Rank Scores (PRS) for CD8-alpha-alpha-positive, alpha-beta intraepithelial T cell within the selected context(s).

Gene ID: A unique numerical identifier for this specific gene.
Symbol: Shortened abbreviation or name that represents this gene.
Ensembl Gene ID: A unique identifier assigned by Ensembl for genomic data mapping.
CSI Score: A combined effect size and statistical significance measure for CD8-alpha-alpha-positive, alpha-beta intraepithelial T cell. Higher scores indicate a stronger, more significant difference in expression.
(Previously described as "Fold Change", but now represents Cliff's Delta × –log10(p).)

Gene ID: A unique numerical identifier for this specific gene.
Symbol: Shortened abbreviation or name that represents this gene.
Ensembl Gene ID: A unique identifier assigned by Ensembl for genomic data mapping.
CSI Score: A combined effect size and statistical significance measure for CD8-alpha-alpha-positive, alpha-beta intraepithelial T cell. Higher scores indicate a stronger, more significant difference in expression.
Average CSI: csi sum / gene count
Cell network configuration

This network visualizes key genes for CD8-alpha-alpha-positive, alpha-beta intraepithelial T cell. It primarily includes:
1. Top genes highly significant for this cell (Num. Top Cell Genes - based on the 'Min. CSI' setting).
2. Any additional specific 'Context Genes' you add below.
The final network is a combined view. Choose an Interaction Source (pathways or protein interactions) and optionally compare CSI scores with a Baseline Cell Type.

Maximum number of selected genes.
Select a context for the baseline cell.
Select a context for the target cell.
Target Cell for CSI:  CD8-alpha-alpha-positive, alpha-beta intraepithelial T cell (CL0000915)

 Legend
Nodes (Genes):
 Query Gene
Node size also reflects Target Cell CSI magnitude.
Node Color (Target Cell CSI in specific network):
 Very High
 High
 Medium
 Low
 Very Low
 N/A or Not Sig.
Edges (Interactions):
 STRING (Protein-Protein)
 ONTOLOGY (Shared Pathway)
 Colors vary by pathway category; default arrow applies.

Loading network (please wait)...

## Summary The [CD8-alpha-alpha-positive, alpha-beta intraepithelial T cell](/details-cell/CL0000915) is a specialized lymphocyte residing within the columnar epithelium of the gastrointestinal tract, characterized by a CD8-alpha-alpha homodimer and an alpha-beta T-cell receptor. The gene significance profile, based on expression specificity (**Overall** `csi_z`), suggests that the identity of this cell is defined less by unique immune effector molecules and more by a heightened and distinct state of metabolic and biosynthetic activity. The high specificity of numerous genes involved in mitochondrial respiration, protein translation, and RNA processing indicates this cell is maintained in a state of high readiness, poised to execute surveillance and effector functions at the gut barrier. ## Key Characteristics and Function The functional profile of the [CD8-alpha-alpha-positive, alpha-beta intraepithelial T cell](/details-cell/CL0000915) is dominated by genes essential for core cellular processes, suggesting its unique role is predicated on the high-level maintenance of these fundamental activities. * **High Metabolic and Energy Production State:** A prominent cluster of top marker genes is associated with mitochondrial function and aerobic respiration. This includes multiple subunits of ATP synthase ([ATP5MG](/details-gene/10632), [ATP5F1E](/details-gene/514), [ATP5MC2](/details-gene/517)) and cytochrome c oxidase ([COX4I1](/details-gene/1327)), as well as the mitochondrial protein [CHCHD2](/details-gene/51142). The high specificity scores for these genes suggest an exceptionally high and constitutive energy demand, consistent with a sentinel cell actively surveying the complex gut microenvironment. * **Elevated Protein Synthesis and RNA Processing:** The cell is characterized by a remarkable enrichment for genes involved in translation and RNA biology. This includes translation elongation factors ([EEF1B2](/details-gene/1933), [EEF1D](/details-gene/1936)), poly(A) binding protein ([PABPC1](/details-gene/26986)), and a suite of heterogeneous nuclear ribonucleoproteins ([HNRNPA1](/details-gene/3178), [HNRNPA2B1](/details-gene/1746), [HNRNPC](/details-gene/3183)). This signature points to a highly active translational machinery, likely required to maintain its protein repertoire for immediate function and to rapidly produce effector molecules upon activation. * **Cytoskeletal Dynamics and Structural Maintenance:** The high specificity of genes like cofilin 1 ([CFL1](/details-gene/1072)) and myosin light chain 6 ([MYL6](/details-gene/4637)) highlights the importance of cytoskeletal regulation. This is crucial for maintaining cell shape and motility within the epithelial layer, as well as for forming immunological synapses during antigen recognition. * **Core Immune Identity:** The high score for Beta-2-microglobulin ([B2M](/details-gene/567)), a component of MHC class I molecules, confirms its T-cell lineage and role in antigen presentation or interaction. Conversely, the very low significance of the B-cell specific marker [CD79A](/details-cell/CL0000973) and the gamma-delta T-cell receptor gene [TRGC1](/details-gene/6966) aligns perfectly with its defined identity as an alpha-beta T cell. ## Clinical Significance and Contextual Roles **Overall**, this cell type appears to be a metabolically primed sentinel of the gut epithelium. Its location positions it as a first responder to pathogens, commensal microbiota, and dietary antigens. The strong expression specificity of fundamental housekeeping genes rather than overt inflammatory mediators suggests a primary role in maintaining tissue homeostasis, mediating tolerance, and executing controlled, rapid immune responses to breach of the epithelial barrier. Dysregulation of this cell population could be central to intestinal pathologies. An over-reactive state might contribute to the chronic inflammation seen in Inflammatory Bowel Disease (IBD) or the tissue damage in Celiac Disease. Conversely, a hypo-responsive state could lead to increased susceptibility to enteric pathogens. The unique metabolic and biosynthetic signature of these cells may represent a therapeutic target for modulating gut-specific immunity. The surprisingly low significance score for the tissue-residency transcription factor [ZNF683](/details-gene/257101) (Hobit) suggests that this IEL subset may utilize an alternative or distinct transcriptional program to establish and maintain its position within the epithelium, a feature that warrants further investigation. ## Potential Mechanisms and Research Directions 1. **Hypothesis: The "Metabolic Readiness" Sentinel Model.** The defining characteristic of this [CD8-alpha-alpha-positive, alpha-beta intraepithelial T cell](/details-cell/CL0000915) is a constitutively high metabolic and translational state. This "readiness" allows it to perform continuous surveillance and mount immediate effector responses upon antigen encounter, bypassing the need for extensive metabolic and transcriptional reprogramming from a quiescent state, which is critical for a frontline immune cell at a dynamic barrier surface. * **Surprising Findings:** The most specific markers for this cell type are not canonical T-cell effector genes (e.g., granzymes, perforin, cytokines) but rather fundamental "housekeeping" genes involved in energy production and protein synthesis. This suggests its identity and function are defined more by the high-intensity regulation of core cellular machinery than by the expression of a unique set of functional molecules. * **Testable Questions:** How does the single-cell metabolic flux (e.g., via SCENITH) of these IELs compare to circulating naive or memory CD8+ T cells? Do these IELs exhibit a faster kinetics of effector protein production post-TCR stimulation compared to their circulating counterparts? 2. **Hypothesis: An Alternative Tissue-Residency Program.** The unique phenotype of this cell, particularly its CD8-alpha-alpha expression and memory characteristics, is maintained by a distinct epigenetic and transcriptional program that may be independent of canonical tissue-residency factors like Hobit ([ZNF683](/details-gene/257101)). The high specificity of histone variants ([H3 3A](/details-gene/3020), [H3 3B](/details-gene/3021)) and ubiquitin ([UBB](/details-gene/7314)) suggests a unique chromatin landscape that poises the cell for its specific function while potentially repressing alternative fates or inflammatory programs. * **Surprising Findings:** The low significance index for [ZNF683](/details-gene/257101), a transcription factor strongly associated with tissue-resident memory T cells (TRM) in other tissues, is unexpected. This implies that residency and function in the gut intraepithelial environment may be governed by a different set of master regulators or a combinatorial code of more ubiquitously expressed factors. * **Testable Questions:** What is the genome-wide chromatin accessibility landscape (via ATAC-seq) of these IELs, and which transcription factor binding motifs are enriched in the accessible regions? Does conditional knockout of H3.3 variants in T cells specifically impair the development or maintenance of this IEL population in the gut?