Details for: CL0001062

Cell ID: CL0001062

Cell Name: effector memory CD8-positive, alpha-beta T cell, terminally differentiated

Description: This cell type is seen in human but not found in the mouse.

Synonyms: CD8+ TEMRA, CD8-positive TEMRA, TEMRA

Selected Context(s): Overall

Gene Significance Landscape

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Score:
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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 effector memory CD8-positive, alpha-beta T cell, terminally differentiated 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 effector memory CD8-positive, alpha-beta T cell, terminally differentiated. 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 effector memory CD8-positive, alpha-beta T cell, terminally differentiated. 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 effector memory CD8-positive, alpha-beta T cell, terminally differentiated. 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:  effector memory CD8-positive, alpha-beta T cell, terminally differentiated (CL0001062)

 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 [effector memory CD8-positive, alpha-beta T cell, terminally differentiated](/details-cell/CL0001062), also known as CD8+ TEMRA, is a mature cytotoxic T lymphocyte characterized by a state of terminal differentiation. The gene significance profile suggests this cell is primed for potent, immediate effector functions, underscored by the high specificity of genes involved in T-cell mediated cytotoxicity and antigen presentation, such as the non-classical MHC class I molecule [HLA E](/details-gene/3133) and its essential component [B2M](/details-gene/567). The cell's molecular signature is dominated by genes supporting high metabolic activity and protein synthesis, consistent with a cell poised for rapid response rather than further proliferation. ## Key Characteristics and Function Analysis of top marker genes, based on expression specificity (`csi_z`), reveals several key functional clusters that define the [CD8+ TEMRA cell](/details-cell/CL0001062). * **Antigen Presentation and Cytotoxicity:** The most significant markers are [HLA E](/details-gene/3133) and [B2M](/details-gene/567), components of the MHC class I antigen presentation pathway. Their high specificity scores indicate a unique role in this cell type. While HLA-E is known for presenting a limited peptide repertoire to receptors on [NK cells](/details-cell/CL0000623) and other lymphocytes, its prominence here suggests a specialized function in regulating cytotoxic responses. The presence of [CD3E](/details-gene/916) confirms the cell's T-cell lineage and its capacity for T-cell receptor-mediated activation. * **High Metabolic Readiness:** A large number of top markers are associated with energy metabolism and protein synthesis, suggesting a state of high metabolic preparedness. This includes key components of the mitochondrial electron transport chain, such as [COX1](/details-gene/4512) and [COX2](/details-gene/4513), and ATP synthesis ([ATP5F1E](/details-gene/514)). This metabolic machinery likely supports the energetic demands of maintaining a cytotoxic-ready state. * **Protein Synthesis and Housekeeping:** The cell exhibits high expression specificity for genes involved in translation ([EEF1D](/details-gene/1936), [TMA7](/details-gene/51372)), protein folding and stability ([UBC](/details-gene/7316)), iron metabolism ([FTL](/details-gene/2512), [FTH1](/details-gene/2495)), and cytoskeletal dynamics ([CFL1](/details-gene/1072), [MYL12A](/details-gene/10627)). This profile is consistent with a cell actively maintaining a large pool of effector proteins. * **Transcriptional and Post-transcriptional Regulation:** The significance of genes like the antiproliferative transcription coregulator [BTG1](/details-gene/694) and the RNA helicase [DDX5](/details-gene/1655) may reflect the regulatory networks that maintain the terminally differentiated state, limiting further proliferation while preserving effector function. The Anti-Markers list does not contain strongly suppressed genes, indicating that the identity of this cell is defined more by the specific expression of its key markers rather than the stark absence of lineage-inappropriate genes. ## Clinical Significance and Contextual Roles The **Overall** context suggests that [CD8+ TEMRA cells](/details-cell/CL0001062) are a population of highly experienced, late-stage effector cells. In a clinical context, these cells are often expanded during chronic viral infections (such as CMV), in certain autoimmune conditions, and with aging. Their terminally differentiated state, potentially reinforced by the expression of antiproliferative genes like [BTG1](/details-gene/694), implies they have limited capacity for self-renewal and are primarily programmed for immediate effector activity. This makes them critical for controlling persistent pathogens but may also contribute to immunosenescence, where an accumulation of these cells could exhaust the pool of more plastic memory T cells. The strong signature for metabolic machinery ([COX1](/details-gene/4512), [COX2](/details-gene/4513)) suggests these cells are not quiescent but are actively maintained in a state of alert. Their function is likely critical in providing a rapid first line of defense upon re-exposure to a known antigen, deploying their cytotoxic payload without the need for extensive proliferation and differentiation. The specific role of [HLA E](/details-gene/3133) as the top marker is of particular interest, as its interactions can deliver both activating and inhibitory signals, suggesting these cells are involved in a complex regulatory crosstalk within the immune system. ## Potential Mechanisms and Research Directions 1. **Hypothesis: CD8+ TEMRA cells are maintained in a state of "metabolic pre-activation" to enable immediate cytotoxic function.** The data reveals an unusually high specificity for genes encoding core components of mitochondrial oxidative phosphorylation ([COX1](/details-gene/4512), [COX2](/details-gene/4513), [ATP5F1E](/details-gene/514)). We hypothesize that rather than being metabolically quiescent like some memory cells, [CD8+ TEMRA cells](/details-cell/CL0001062) constitutively maintain a high level of oxidative phosphorylation. This metabolic state may not be for proliferation but to fuel the constant synthesis and readiness of cytotoxic granules and to power immediate effector functions upon T-cell receptor engagement, bypassing the typical metabolic switch required by other memory subsets. * **Surprising Findings:** It is notable that core metabolic genes rank higher in specificity than many canonical cytotoxic effector genes (e.g., granzymes, perforin). This suggests that the *potential* to be an effector, as defined by metabolic capacity, is a more unique and defining characteristic of the TEMRA state than the effector molecules themselves. * **Testable Questions:** Does the basal oxygen consumption rate (OCR) of [CD8+ TEMRA cells](/details-cell/CL0001062) significantly exceed that of central memory [CD8+ T cells](/details-cell/CL0000625)? Furthermore, does pharmacologic inhibition of the electron transport chain more acutely impair the immediate (within 1-2 hours) cytotoxic capacity of TEMRA cells compared to other memory T-cell subsets? 2. **Hypothesis: HLA-E expression on CD8+ TEMRA cells serves as a key regulatory checkpoint to prevent off-target activation and mediate interactions with the innate immune system.** The top marker is the non-classical MHC molecule [HLA E](/details-gene/3133), which typically presents a restricted set of self-peptides and interacts with NK cell receptors like NKG2A (inhibitory) and NKG2C (activating). We hypothesize that the high expression of [HLA E](/details-gene/3133) on [CD8+ TEMRA cells](/details-cell/CL0001062) is not primarily for presenting foreign antigens but for self-regulation and communication. This HLA-E surface expression could serve as a ligand for inhibitory receptors on adjacent cells (or even on the TEMRA cells themselves), raising their activation threshold to prevent unwarranted cytotoxicity. Conversely, it could engage activating receptors on [NK cells](/details-cell/CL0000623), coordinating a broader immune response. * **Surprising Findings:** The most specific marker for a highly specialized adaptive immune cell is a molecule more commonly associated with innate immune regulation and NK cell function. This blurs the line between the adaptive and innate roles of this lymphocyte subset. * **Testable Questions:** Does antibody-mediated blocking of [HLA E](/details-gene/3133) on the surface of [CD8+ TEMRA cells](/details-cell/CL0001062) lower their threshold for activation by sub-optimal TCR stimulation? Additionally, do [CD8+ TEMRA cells](/details-cell/CL0001062) modulate the cytotoxic activity of co-cultured NKG2A+ or NKG2C+ [NK cells](/details-cell/CL0000623) in an HLA-E-dependent manner?