Details for: CL0000972

Cell ID: CL0000972

Cell Name: class switched memory B cell

Description: Per DSD: Class switched memory B cells are also reportedly CD48-positive, CD229-positive, and CD352-positive.

Synonyms: class switched memory B lymphocyte, class switched memory B-cell, class switched memory B-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 class switched memory B 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 class switched memory B 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 class switched memory B 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 class switched memory B 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:  class switched memory B cell (CL0000972)

 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 [class switched memory B cell](/details-cell/CL0000972) is a mature B lymphocyte responsible for maintaining long-term humoral immunity. It is characterized by having undergone immunoglobulin class-switch recombination, enabling it to produce antibody isotypes such as IgG, IgA, or IgE upon re-exposure to a specific antigen. The gene significance profile suggests this cell is not merely quiescent but is maintained in a state of high metabolic and translational readiness, poised for rapid reactivation. Strikingly, its most specific markers are components of the MHC class I antigen presentation pathway, particularly [B2M](/details-gene/567) and the non-classical molecule [HLA E](/details-gene/3133), indicating a specialized role in immune regulation and survival, potentially through interactions with natural killer (NK) cells. ## Key Characteristics and Function Analysis of gene significance in the **Overall** context reveals that the identity and function of the [class switched memory B cell](/details-cell/CL0000972) are defined by several key biological processes. * **Antigen Presentation and Immune Regulation:** The two most specific markers, [B2M](/details-gene/567) (CSI 136.49) and [HLA E](/details-gene/3133) (CSI 124.81), are integral to MHC class I antigen presentation. While B cells are professional antigen-presenting cells (APCs) via MHC class II (evidenced by the high specificity of [HLA DPA1](/details-gene/3113)), the exceptional specificity of these class I components suggests a crucial, defining role. HLA-E is known to present a limited peptide repertoire and serves as a ligand for the inhibitory receptor NKG2A on NK cells. This may indicate a primary function in self-recognition and survival, allowing these long-lived memory cells to evade NK cell-mediated cytotoxicity. * **High Metabolic and Translational Poise:** A significant number of top markers are involved in core cellular energetics and protein synthesis. This includes mitochondrial genes critical for oxidative phosphorylation such as [COX2](/details-gene/4513) (CSI 120.01), [COX1](/details-gene/4512) (CSI 114.05), and [COX7C](/details-gene/1350) (CSI 95.23), as well as genes essential for protein translation and stability like [PABPC1](/details-gene/26986) (CSI 116.34) and [EEF1B2](/details-gene/1933) (CSI 109.45). This signature is consistent with a cell that is metabolically primed for rapid differentiation and antibody production upon reactivation, rather than being in a state of deep dormancy. The high specificity of iron-storage proteins [FTH1](/details-gene/2495) and [FTL](/details-gene/2512) further supports this state of metabolic preparedness. * **Transcriptional and Cell Cycle Regulation:** The functional profile is balanced by the specific expression of regulatory proteins. The B-cell translocation gene 1, [BTG1](/details-gene/694) (CSI 115.14), is a known anti-proliferative factor whose expression is maximal in the G0/G1 phases of the cell cycle ([Link](https://doi.org/10.1002/j.1460-2075.1992.tb05213.x)). Its high specificity in these cells suggests a mechanism that actively maintains quiescence while the cell remains metabolically active. Additionally, RNA-binding proteins and helicases like [DDX5](/details-gene/1655), [YBX1](/details-gene/4904), and [HNRNPA2B1](/details-gene/3181) are prominent, indicating that post-transcriptional regulation is critical for maintaining the memory state. * **Cellular Identity:** The low significance scores for markers associated with other lineages, such as the T-cell receptor alpha constant gene [TRAC](/details-gene/28755) (CSI 3.00), confirm the distinct B-cell identity of this population. The relatively low specificity score for [CD72](/details-gene/971) (CSI 3.67), a pan-B cell marker, may suggest its expression is less defining for this mature subset compared to other B cell populations. ## Clinical Significance and Contextual Roles **Overall**, the gene expression profile of [class switched memory B cells](/details-cell/CL0000972) highlights mechanisms central to their long-term survival and function, with implications for immunity and disease. The prominence of the [HLA E](/details-gene/3133)-[B2M](/details-gene/567) axis suggests a crucial mechanism for immune evasion that ensures the persistence of the memory B cell pool. By displaying inhibitory signals to NK cells, these memory cells can survive for decades, providing a durable defense against pathogens. Dysregulation of this axis could potentially compromise long-term immunity or, conversely, contribute to the survival of malignant B cells in certain lymphomas. The high specificity of the anti-proliferative gene [BTG1](/details-gene/694) is clinically relevant. This gene is involved in a chromosomal translocation t(8;12) found in B-cell chronic lymphocytic leukemia ([Link](https://doi.org/10.1002/j.1460-2075.1992.tb05213.x)), highlighting its role as a potential tumor suppressor in B lymphocytes. Its defining expression in healthy memory B cells underscores the importance of tightly controlled cell cycle entry for this population, a process that is subverted during malignant transformation. Furthermore, the cell's state of high metabolic readiness, driven by robust expression of mitochondrial and translational machinery, is fundamental to its role in anamnestic responses. This pre-primed state allows for a swifter and more potent antibody response upon secondary infection compared to the primary response from naive B cells. Understanding the factors that maintain this poised state could offer therapeutic avenues to enhance vaccine efficacy or modulate autoimmune responses where memory B cells are pathogenic. ## Potential Mechanisms and Research Directions 1. **Hypothesis:** The high specificity of the MHC class I components [HLA E](/details-gene/3133) and [B2M](/details-gene/567) is not for traditional antigen presentation to T cells, but rather constitutes a primary survival mechanism for long-lived [class switched memory B cells](/details-cell/CL0000972). This expression provides a constitutive inhibitory signal to NK cells via the NKG2A/CD94 receptor, protecting the memory B cell reservoir from innate immune surveillance and ensuring its persistence over time. * **Surprising Findings:** It is unexpected that the most specific genetic markers for a cell type renowned for MHC class II-mediated antigen presentation are components of the MHC class I pathway. This suggests that interaction with the innate immune system (specifically NK cells) may be as fundamental to the identity of a memory B cell as its interaction with T helper cells. * **Testable Questions:** Does the selective depletion of NK cells in vivo lead to an expansion or altered persistence of the class-switched memory B cell compartment? Furthermore, does blocking the HLA-E:NKG2A interaction in co-culture assays result in increased NK cell-mediated lysis of memory B cells compared to naive B cells? 2. **Hypothesis:** [Class switched memory B cells](/details-cell/CL0000972) exist in a unique "revved and ready" state, characterized by the co-expression of genes driving high metabolic potential (e.g., [COX1](/details-gene/4512), [COX2](/details-gene/4513)) and potent cell cycle inhibitors (e.g., [BTG1](/details-gene/694)). This state allows the cell to maintain the energetic and translational capacity for rapid reactivation while a strong molecular "brake" actively prevents inappropriate proliferation, ensuring the stability of the memory pool until a cognate antigen is encountered. * **Surprising Findings:** The concurrent high specificity of genes for both robust mitochondrial respiration and potent cell cycle arrest is a paradox. It indicates that the quiescent state of memory B cells is not a passive, low-energy state but an actively maintained, energy-dependent condition of readiness. * **Testable Questions:** Do [class switched memory B cells](/details-cell/CL0000972) exhibit a higher basal mitochondrial oxygen consumption rate than naive B cells? Does shRNA-mediated knockdown of [BTG1](/details-gene/694) in these cells lower the threshold for activation, leading to proliferation in response to sub-optimal stimuli (e.g., bystander cytokine stimulation without BCR engagement)?