Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 3 complete abstracts (518 words), 9 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
Morphologic alteration of small B lymphocytes or T lymphocytes in culture into large blast-like cells able to synthesize DNA and RNA and to divide mitotically. It is induced by interleukins; mitogens such as phytohemagglutinins, and by specific antigens. It may also occur in vivo as in graft rejection.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Activation, Lymphocyte; Blast Transformation; Blastogenesis; Transformation, Lymphocyte; Lymphocyte Transformation; Transformation, Lymphoblast; Lymphoblast Transformation; Transformation, Blast.
Where it fits in the MeSH classification
- Broader topics
- Immunologic Tests; Immunity, Cellular; Immune System Phenomena
- Narrower topics
- Cross-Priming
- See also
- Blast Crisis
Related concepts
- Lymphocytes
- Interleukins
- Mitogens
- Phytohemagglutinins
- Antigens
- Graft Rejection
Research landscape
PubMed indexes 118,630 records tagged with the MeSH heading “Lymphocyte Activation” (counts retrieved 2026-10-29). 7,999 of them (6.7%) were published from 2020 onward, and the busiest period so far is through 1999 with 63,803 records.
Reviews account for 10,437 records (8.8%) and meta-analyses for 25. Randomized controlled trials number 735 (0.6%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 63,803 |
| 2000-2009 | 25,348 |
| 2010-2019 | 21,480 |
| 2020 onward | 7,999 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 10,437 | 8.8% |
| Meta-analyses | 25 | 0.0% |
| Randomized controlled trials | 735 | 0.6% |
Method: PubMed query "Lymphocyte Activation"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-29.
Reading the evidence in immunology
Immune responses are studied in model organisms, in cells from donors and in patients, and the same pathway can behave differently across these settings. Mouse immune systems differ from human ones in important ways, and blood measurements may not reflect what happens in tissues. Clinical conclusions about immune-mediated disease or immunotherapy come mainly from controlled trials and long-term cohorts. Check the species and tissue studied, whether markers were linked to outcomes patients notice, and the follow-up time.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Cancer cells impair monocyte-mediated T cell stimulation to evade immunity | 2025 | Research article Design not recorded in structured metadata | 151 | cc by PMID 39604727 · DOI · PMC7617236 |
| Reproducible single-cell annotation of programs underlying T cell subsets, activation states and functions | 2025 | Research article Design not recorded in structured metadata | 45 | cc by PMID 40903640 · DOI · PMC12446064 |
| Long COVID involves activation of proinflammatory and immune exhaustion pathways | 2026 | Research article Design not recorded in structured metadata | 40 | cc by PMID 41388153 · DOI · PMC12764429 |
Cancer cells impair monocyte-mediated T cell stimulation to evade immunity [1]
Abstract reading summary — source excerpts
- Opening excerpt
- The tumour microenvironment is programmed by cancer cells and substantially influences anti-tumour immune responses1,2.
- Closing excerpt
- Together, our work uncovers a central role of inflammatory monocytes in intratumoral T cell stimulation, elucidates how oncogenic signalling disrupts T cell responses through counter-regulation of PGE2 and IFN-I, and proposes rational combination therapies to enhance immunotherapies.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (203 words)
The tumour microenvironment is programmed by cancer cells and substantially influences anti-tumour immune responses1,2. Within the tumour microenvironment, CD8+ T cells undergo full effector differentiation and acquire cytotoxic anti-tumour functions in specialized niches3-7. Although interactions with type 1 conventional dendritic cells have been implicated in this process3-5,8-10, the underlying cellular players and molecular mechanisms remain incompletely understood. Here we show that inflammatory monocytes can adopt a pivotal role in intratumoral T cell stimulation. These cells express Cxcl9, Cxcl10 and Il15, but in contrast to type 1 conventional dendritic cells, which cross-present antigens, inflammatory monocytes obtain and present peptide-major histocompatibility complex class I complexes from tumour cells through 'cross-dressing'. Hyperactivation of MAPK signalling in cancer cells hampers this process by coordinately blunting the production of type I interferon (IFN-I) cytokines and inducing the secretion of prostaglandin E2 (PGE2), which impairs the inflammatory monocyte state and intratumoral T cell stimulation. Enhancing IFN-I cytokine production and blocking PGE2 secretion restores this process and re-sensitizes tumours to T cell-mediated immunity. Together, our work uncovers a central role of inflammatory monocytes in intratumoral T cell stimulation, elucidates how oncogenic signalling disrupts T cell responses through counter-regulation of PGE2 and IFN-I, and proposes rational combination therapies to enhance immunotherapies.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 39604727 · DOI · PMC7617236
Reproducible single-cell annotation of programs underlying T cell subsets, activation states and functions [2]
Abstract reading summary — source excerpts
- Opening excerpt
- T cells recognize antigens and induce specialized gene expression programs (GEPs), enabling functions like proliferation, cytotoxicity and cytokine production.
- Closing excerpt
- Our software package starCAT generalizes this framework, enabling reproducible annotation in other cell types and tissues.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (150 words)
T cells recognize antigens and induce specialized gene expression programs (GEPs), enabling functions like proliferation, cytotoxicity and cytokine production. Traditionally, different T cell classes are thought to exhibit mutually exclusive responses, including TH1, TH2 and TH17 programs. However, single-cell RNA sequencing has revealed a continuum of T cell states without clearly distinct subsets, necessitating new analytical frameworks. Here, we introduce T-CellAnnoTator (TCAT), a pipeline that improves T cell characterization by simultaneously quantifying predefined GEPs capturing activation states and cellular subsets. Analyzing 1,700,000 T cells from 700 individuals spanning 38 tissues and five disease contexts, we identify 46 reproducible GEPs reflecting core T cell functions including proliferation, cytotoxicity, exhaustion and effector states. We experimentally demonstrate new activation programs and apply TCAT to characterize activation GEPs that predict immune checkpoint inhibitor response across multiple tumor types. Our software package starCAT generalizes this framework, enabling reproducible annotation in other cell types and tissues.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 40903640 · DOI · PMC12446064
Long COVID involves activation of proinflammatory and immune exhaustion pathways [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Long COVID (LC) involves a spectrum of chronic symptoms after acute severe acute respiratory syndrome coronavirus 2 infection.
- Closing excerpt
- These data suggest that LC is characterized by persistent activation of chronic inflammatory pathways, suggesting new therapeutic targets and potential biomarkers of disease.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (165 words)
Long COVID (LC) involves a spectrum of chronic symptoms after acute severe acute respiratory syndrome coronavirus 2 infection. Current hypotheses for the pathogenesis of LC include persistent virus, tissue damage, autoimmunity, endocrine insufficiency, immune dysfunction and complement activation. We performed immunological, virological, transcriptomic and proteomic analyses from a cohort of 142 individuals between 2020 and 2021, including uninfected controls (n = 35), acutely infected individuals (n = 54), convalescent controls (n = 24) and patients with LC (n = 28). The LC group was characterized by persistent immune activation and proinflammatory responses for more than 180 days after initial infection compared with convalescent controls, including upregulation of JAK-STAT, interleukin-6, complement, metabolism and T cell exhaustion pathways. Similar findings were observed in a second cohort enrolled between 2023 and 2024, including convalescent controls (n = 20) and patients with LC (n = 18). These data suggest that LC is characterized by persistent activation of chronic inflammatory pathways, suggesting new therapeutic targets and potential biomarkers of disease.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41388153 · DOI · PMC12764429
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article The diverse functions of the PD1 inhibitory pathway [4]
- Research article T follicular helper cell differentiation, function, and roles in disease [5]
- Research article CD8+ cytotoxic T lymphocytes in cancer immunotherapy: A review [6]
- Research article CXCL9, CXCL10, CXCL11/CXCR3 axis for immune activation - A target for novel cancer therapy [7]
- Research article CD69: from activation marker to metabolic gatekeeper [8]
- Research article Dendritic Cells and Cancer Immunity [9]
References
- Elewaut A, Estivill G, Bayerl F, Castillon L, Novatchkova M, Pottendorfer E, et al.. Cancer cells impair monocyte-mediated T cell stimulation to evade immunity. . 2025. PMID 39604727 · DOI · PMC7617236
- Kotliar D, Curtis M, Agnew R, Weinand K, Nathan A, Baglaenko Y, et al.. Reproducible single-cell annotation of programs underlying T cell subsets, activation states and functions. . 2025. PMID 40903640 · DOI · PMC12446064
- Aid M, Boero-Teyssier V, McMahan K, Dang R, Doyle M, Belabbaci N, et al.. Long COVID involves activation of proinflammatory and immune exhaustion pathways. . 2026. PMID 41388153 · DOI · PMC12764429
- Sharpe AH, Pauken KE. The diverse functions of the PD1 inhibitory pathway. Nat Rev Immunol. 2018. PMID 28990585 · DOI
- Crotty S. T follicular helper cell differentiation, function, and roles in disease. Immunity. 2014. PMID 25367570 · DOI · PMC4223692
- Farhood B, Najafi M, Mortezaee K. CD8+ cytotoxic T lymphocytes in cancer immunotherapy: A review. J Cell Physiol. 2019. PMID 30520029 · DOI
- Tokunaga R, Zhang W, Naseem M, Puccini A, Berger MD, Soni S, et al.. CXCL9, CXCL10, CXCL11/CXCR3 axis for immune activation - A target for novel cancer therapy. Cancer Treat Rev. 2018. PMID 29207310 · DOI · PMC5801162
- Cibrián D, Sánchez-Madrid F. CD69: from activation marker to metabolic gatekeeper. Eur J Immunol. 2017. PMID 28475283 · DOI · PMC6485631
- Gardner A, Ruffell B. Dendritic Cells and Cancer Immunity. Trends Immunol. 2016. PMID 27793569 · DOI · PMC5135568
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-29.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.