Details for: CL0000934

Cell ID: CL0000934

Cell Name: CD4-positive, alpha-beta cytotoxic T cell

Description: A CD4-positive, alpha-beta T cell that has cytotoxic function.

Synonyms: CD4-positive, alpha-beta cytotoxic T lymphocyte, CD4-positive, alpha-beta cytotoxic T-cell, CD4-positive, alpha-beta cytotoxic T-lymphocyte

Selected Context(s): Overall

Gene Significance Landscape

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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 CD4-positive, alpha-beta cytotoxic 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 CD4-positive, alpha-beta cytotoxic 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 CD4-positive, alpha-beta cytotoxic 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 CD4-positive, alpha-beta cytotoxic 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:  CD4-positive, alpha-beta cytotoxic T cell (CL0000934)

 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.

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## Summary The [CD4-positive, alpha-beta cytotoxic T cell](/details-cell/CL0000934) is a specialized lymphocyte subset that combines the canonical CD4 co-receptor expression with the functional capacity for direct cell-mediated cytotoxicity. **Overall**, the gene significance profile suggests this cell is defined by a state of high metabolic readiness and robust intercellular communication machinery. The top markers by expression specificity ([csi_z](/help/calculations)) are dominated by genes involved in antigen presentation, such as [B2M](/details-gene/567) and [HLA E](/details-gene/3133), and components of the mitochondrial respiratory chain, including [COX1](/details-gene/4512). This signature indicates a cell primed for both recognizing and interacting with target cells, while possessing the energetic capacity required to execute its cytotoxic effector program. ## Key Characteristics and Function Analysis of the top defining genes reveals several core functional clusters that characterize the [CD4-positive, alpha-beta cytotoxic T cell](/details-cell/CL0000934). * **Antigen Presentation and Immune Recognition:** The highest-scoring markers, [B2M](/details-gene/567) (CSI: 77.78) and [HLA E](/details-gene/3133) (CSI: 62.20), underscore the critical importance of antigen presentation pathways in defining this cell's identity. [B2M](/details-gene/567) is an essential component of MHC class I molecules, while [HLA E](/details-gene/3133) is a non-classical MHC class Ib molecule involved in modulating responses of both T cells and NK cells. Their high specificity suggests this cell is heavily engaged in immune surveillance and communication, potentially presenting antigens or regulating the activity of other lymphocytes. The expression of [GNLY](/details-gene/10578), a key cytolytic protein, directly confirms its cytotoxic potential ([Link](https://pubmed.ncbi.nlm.nih.gov/2434598/)). * **High Metabolic Activity:** A prominent signature of this cell is its high metabolic state, evidenced by the specificity of multiple genes involved in oxidative phosphorylation. This includes mitochondrial-encoded genes like [COX1](/details-gene/4512) and [COX2](/details-gene/4513), as well as nuclear-encoded components like [ATP5F1E](/details-gene/514) and [COX4I1](/details-gene/1327). This suggests that a heightened capacity for ATP production is not just a general feature but a specific, defining characteristic required to fuel the energetically demanding processes of immune activation, proliferation, and the synthesis and release of cytotoxic granules. * **Dynamic Cytoskeletal and Translational Machinery:** The cell exhibits high specific expression of genes involved in maintaining cellular structure and function. This includes cytoskeletal regulators like [CFL1](/details-gene/1072) (cofilin) and myosin light chains ([MYL6](/details-gene/4637), [MYL12A](/details-gene/10627)), which are crucial for cell motility and the formation of the immunological synapse. Furthermore, high scores for translation elongation factors ([EEF1B2](/details-gene/1933), [EEF1D](/details-gene/1936)) and ubiquitin ([UBC](/details-gene/7316)) point to a robust capacity for protein synthesis and turnover, likely supporting the rapid production of effector molecules upon activation. * **Lineage Confirmation:** The cell's identity as an alpha-beta T cell is further solidified by the lack of significant expression of T-cell receptor gamma chain genes, such as [TRGC1](/details-gene/6966) and [TRGC2](/details-gene/6967), which serve as effective anti-markers. Similarly, the low specificity score for interferon-gamma ([IFNG](/details-gene/3458)) may suggest that while the cell can produce this cytokine, it is not as defining a feature as its cytotoxic and metabolic profiles when compared to other immune cell types like canonical Th1 cells. ## Clinical Significance and Contextual Roles Given its unique combination of CD4 expression and cytotoxic function, the [CD4-positive, alpha-beta cytotoxic T cell](/details-cell/CL0000934) is likely a key player in both anti-viral and anti-tumor immunity. Its ability to directly kill target cells, as indicated by markers like [GNLY](/details-gene/10578), places it in a critical effector role. The high specificity of genes like [TPT1](/details-gene/7178) (Translationally-Controlled Tumor Protein) and [S100A6](/details-gene/6277) (Calcyclin), which are often dysregulated in cancer ([Link](https://doi.org/10.1016/s0021-9258(18)67137-6/)), suggests this cell type may be particularly relevant in the tumor microenvironment. The cell's pronounced metabolic signature points to a state of high activation and effector function. In clinical contexts, a high abundance of these cells could be a biomarker for an active and effective cytotoxic immune response. The strong expression of [TXNIP](/details-gene/10628), an inhibitor of the antioxidant protein thioredoxin, may indicate that this cell operates under high levels of oxidative stress, a condition often found during robust immune responses or within inflamed tissues. The unique ability to potentially recognize antigens via MHC class II (through CD4) while killing cells that present antigens via MHC class I could allow it to bridge helper and killer T cell functions, making it a versatile asset in complex disease settings. ## Potential Mechanisms and Research Directions 1. **Hypothesis:** The unique metabolic profile, characterized by the high specificity of certain cytochrome c oxidase (COX) subunits ([COX1](/details-gene/4512), [COX2](/details-gene/4513)) but not others ([COX3](/details-gene/4514), [COX7A2](/details-gene/1347)), reflects a specific configuration of the mitochondrial electron transport chain. This adaptation may optimize energy production to sustain prolonged cytotoxic activity and survival, particularly in challenging microenvironments like solid tumors where resources are scarce. * **Surprising Findings:** It is noteworthy that not all subunits of a key metabolic complex like cytochrome c oxidase show high specificity. This differential signature implies a highly regulated and specific metabolic adaptation rather than a simple global increase in mitochondrial biogenesis. * **Testable Questions:** Does the selective knockout or inhibition of the specifically expressed COX subunits ([COX1](/details-gene/4512), [COX4I1](/details-gene/1327)) in [CD4-positive, alpha-beta cytotoxic T cells](/details-cell/CL0000934) impair their killing efficiency or long-term persistence more significantly than in conventional [CD8-positive, alpha-beta T cells](/details-cell/CL0000625)? 2. **Hypothesis:** The pronounced specificity of antigen presentation molecules ([B2M](/details-gene/567), [HLA E](/details-gene/3133)) suggests that a primary, defining function of this cell, beyond direct killing, is to actively modulate the local immune response. By acting as non-professional antigen-presenting cells via MHC class I and engaging with NK cells via [HLA E](/details-gene/3133), these CD4+ cytotoxic cells may serve as critical coordinators that amplify or regulate subsequent waves of the anti-tumor or anti-viral response. * **Surprising Findings:** The fact that antigen presentation machinery components are the most specific markers, even more so than direct cytotoxic effector molecules like [GNLY](/details-gene/10578), elevates the cell's role from a simple "killer" to a more complex "killer-communicator." This suggests its identity is equally defined by its ability to interact with and influence other immune cells. * **Testable Questions:** Using in vitro co-culture systems, can activated [CD4-positive, alpha-beta cytotoxic T cells](/details-cell/CL0000934) process and present exogenous antigens on their MHC class I molecules to activate naive [CD8-positive, alpha-beta T cells](/details-cell/CL0000625)? Furthermore, does blocking the [HLA E](/details-gene/3133) interaction on these cells alter NK cell activation and cytotoxicity in the co-culture?