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: 4 complete abstracts (720 words), 10 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
A subset of activated T cells generated in response to primary immune challenge or immunization upon re-challenge (see immunologic memory). Memory T cells feature many discrete properties indicative of various differentiation such as expression pattern of ccr7 receptors and can be divided into central memory and effector memory T cells.
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: Memory T Cell; T Cell, Memory; Memory T Lymphocytes; Lymphocyte, Memory T; Lymphocytes, Memory T; Memory T Lymphocyte; T Lymphocyte, Memory; T Lymphocytes, Memory.
Where it fits in the MeSH classification
- Broader topics
- Immunological Memory Cells; T-Lymphocyte Subsets
Related concepts
- Immunologic Memory
- Ccr7 Receptors
Research landscape
PubMed indexes 1,249 records tagged with the MeSH heading “Memory T Cells” (counts retrieved 2026-10-31). 1,248 of them (99.9%) were published from 2020 onward, and the busiest period so far is 2020 onward with 1,248 records.
Reviews account for 193 records (15.5%) and meta-analyses for 2. Randomized controlled trials number 12 (1.0%) 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 | 1 |
| 2000-2009 | 0 |
| 2010-2019 | 0 |
| 2020 onward | 1,248 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 193 | 15.5% |
| Meta-analyses | 2 | 0.2% |
| Randomized controlled trials | 12 | 1.0% |
Method: PubMed query "Memory T Cells"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-31.
Reading the evidence in anatomy and physiology
Anatomy describes how body structures are built and physiology describes how they normally work, so most findings here are descriptive or mechanistic rather than evidence about treatment. Much of what is known comes from dissection, imaging, tissue studies and experiments in animals, and measurements in healthy volunteers can differ from those in people with disease or at different ages. Normal ranges vary between individuals and populations. Check whether a result was measured in people or in another species, the age and health of the participants, and the method used.
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 |
|---|---|---|---|---|
| Pre-existing polymerase-specific T cells expand in abortive seronegative SARS-CoV-2 | 2022 | Research article Design not recorded in structured metadata | 383 | cc by PMID 34758478 · DOI · PMC8732273 |
| Unadjuvanted intranasal spike vaccine elicits protective mucosal immunity against sarbecoviruses | 2022 | Research article Design not recorded in structured metadata | 325 | cc by PMID 36302057 · DOI · PMC9798903 |
| Cross-reactive memory T cells associate with protection against SARS-CoV-2 infection in COVID-19 contacts | 2022 | Research article Design not recorded in structured metadata | 298 | cc by PMID 35013199 · DOI · PMC8748880 |
| Antigen reactivity defines tissue-resident memory and exhausted T cells in tumors | 2026 | Research article Design not recorded in structured metadata | 23 | cc by PMID 41461987 · DOI · PMC12764432 |
Pre-existing polymerase-specific T cells expand in abortive seronegative SARS-CoV-2 [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Individuals with potential exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) do not necessarily develop PCR or antibody positivity, suggesting that some individuals may clear subclinical infection before seroconversion.
- Closing excerpt
- Our data highlight RTC-specific T cells as targets for vaccines against endemic and emerging Coronaviridae.
- 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 (258 words)
Individuals with potential exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) do not necessarily develop PCR or antibody positivity, suggesting that some individuals may clear subclinical infection before seroconversion. T cells can contribute to the rapid clearance of SARS-CoV-2 and other coronavirus infections1-3. Here we hypothesize that pre-existing memory T cell responses, with cross-protective potential against SARS-CoV-2 (refs. 4-11), would expand in vivo to support rapid viral control, aborting infection. We measured SARS-CoV-2-reactive T cells, including those against the early transcribed replication-transcription complex (RTC)12,13, in intensively monitored healthcare workers (HCWs) who tested repeatedly negative according to PCR, antibody binding and neutralization assays (seronegative HCWs (SN-HCWs)). SN-HCWs had stronger, more multispecific memory T cells compared with a cohort of unexposed individuals from before the pandemic (prepandemic cohort), and these cells were more frequently directed against the RTC than the structural-protein-dominated responses observed after detectable infection (matched concurrent cohort). SN-HCWs with the strongest RTC-specific T cells had an increase in IFI27, a robust early innate signature of SARS-CoV-2 (ref. 14), suggesting abortive infection. RNA polymerase within RTC was the largest region of high sequence conservation across human seasonal coronaviruses (HCoV) and SARS-CoV-2 clades. RNA polymerase was preferentially targeted (among the regions tested) by T cells from prepandemic cohorts and SN-HCWs. RTC-epitope-specific T cells that cross-recognized HCoV variants were identified in SN-HCWs. Enriched pre-existing RNA-polymerase-specific T cells expanded in vivo to preferentially accumulate in the memory response after putative abortive compared to overt SARS-CoV-2 infection. Our data highlight RTC-specific T cells as targets for vaccines against endemic and emerging Coronaviridae.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 34758478 · DOI · PMC8732273
Unadjuvanted intranasal spike vaccine elicits protective mucosal immunity against sarbecoviruses [2]
Abstract reading summary — source excerpts
- Opening excerpt
- The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has highlighted the need for vaccines that not only prevent disease but also prevent transmission.
- Closing excerpt
- Using divergent spike proteins, prime and spike enables the induction of cross-reactive immunity against sarbecoviruses.
- 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 (124 words)
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has highlighted the need for vaccines that not only prevent disease but also prevent transmission. Parenteral vaccines induce robust systemic immunity but poor immunity at the respiratory mucosa. We developed a vaccine strategy that we call "prime and spike," which leverages existing immunity generated by primary vaccination (prime) to elicit mucosal immune memory within the respiratory tract by using unadjuvanted intranasal spike boosters (spike). We show that prime and spike induces robust resident memory B and T cell responses, induces immunoglobulin A at the respiratory mucosa, boosts systemic immunity, and completely protects mice with partial immunity from lethal SARS-CoV-2 infection. Using divergent spike proteins, prime and spike enables the induction of cross-reactive immunity against sarbecoviruses.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 36302057 · DOI · PMC9798903
Cross-reactive memory T cells associate with protection against SARS-CoV-2 infection in COVID-19 contacts [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Cross-reactive immune responses to SARS-CoV-2 have been observed in pre-pandemic cohorts and proposed to contribute to host protection.
- Closing excerpt
- Our results are thus consistent with pre-existing non-spike cross-reactive memory T cells protecting SARS-CoV-2-naïve contacts from infection, thereby supporting the inclusion of non-spike antigens in second-generation vaccines.
- 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 (158 words)
Cross-reactive immune responses to SARS-CoV-2 have been observed in pre-pandemic cohorts and proposed to contribute to host protection. Here we assess 52 COVID-19 household contacts to capture immune responses at the earliest timepoints after SARS-CoV-2 exposure. Using a dual cytokine FLISpot assay on peripheral blood mononuclear cells, we enumerate the frequency of T cells specific for spike, nucleocapsid, membrane, envelope and ORF1 SARS-CoV-2 epitopes that cross-react with human endemic coronaviruses. We observe higher frequencies of cross-reactive (p = 0.0139), and nucleocapsid-specific (p = 0.0355) IL-2-secreting memory T cells in contacts who remained PCR-negative despite exposure (n = 26), when compared with those who convert to PCR-positive (n = 26); no significant difference in the frequency of responses to spike is observed, hinting at a limited protective function of spike-cross-reactive T cells. Our results are thus consistent with pre-existing non-spike cross-reactive memory T cells protecting SARS-CoV-2-naïve contacts from infection, thereby supporting the inclusion of non-spike antigens in second-generation vaccines.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 35013199 · DOI · PMC8748880
Antigen reactivity defines tissue-resident memory and exhausted T cells in tumors [4]
Abstract reading summary — source excerpts
- Opening excerpt
- CD8+ T cells are an important weapon in the therapeutic armamentarium against cancer.
- Closing excerpt
- These results highlight unique functions for TRM and TEX cells in tumor control, underscoring the need for distinct strategies to harness these populations for cancer therapies.
- 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 (180 words)
CD8+ T cells are an important weapon in the therapeutic armamentarium against cancer. While CD8+CD103+ T cells with a tissue-resident memory T (TRM) cell phenotype are associated with favorable prognoses, the tumor microenvironment also contains dysfunctional exhausted T (TEX) cells that exhibit a variety of TRM-like features. Here we deconvolute TRM and TEX cells across human cancers, ascribing markers and gene signatures that distinguish these populations and enable their functional distinction. Although TRM cells have superior functionality and are associated with long-term survival post-tumor resection, they are not associated with responsiveness to immune checkpoint blockade. Tumor-associated TEX and TRM cells are clonally distinct, with the latter comprising tumor-independent bystanders and tumor-specific cells segregated from cognate antigen. Intratumoral TRM cells can be forced toward an exhausted fate when chronic antigen stimulation occurs, indicating that the presence or absence of continuous antigen exposure within the microenvironment is the key distinction between tumor-associated TEX and TRM populations. These results highlight unique functions for TRM and TEX cells in tumor control, underscoring the need for distinct strategies to harness these populations for cancer therapies.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41461987 · DOI · PMC12764432
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 CD4+ T cell memory [5]
- Research article Targeting memory T cell metabolism to improve immunity [6]
- Research article Tissue resident memory T cells in the respiratory tract [7]
- Research article Hallmarks of the aging T-cell system [8]
- Research article The Multifaceted Role of Tissue-Resident Memory T Cells [9]
- Research article Unlocking the full potential of memory T cells in adoptive T cell therapy for hematologic malignancies [10]
References
- Swadling L, Diniz MO, Schmidt NM, Amin OE, Chandran A, Shaw E, et al.. Pre-existing polymerase-specific T cells expand in abortive seronegative SARS-CoV-2. . 2022. PMID 34758478 · DOI · PMC8732273
- Mao T, Israelow B, Peña-Hernández MA, Suberi A, Zhou L, Luyten S, et al.. Unadjuvanted intranasal spike vaccine elicits protective mucosal immunity against sarbecoviruses. . 2022. PMID 36302057 · DOI · PMC9798903
- Kundu R, Narean JS, Wang L, Fenn J, Pillay T, Fernandez ND, et al.. Cross-reactive memory T cells associate with protection against SARS-CoV-2 infection in COVID-19 contacts. . 2022. PMID 35013199 · DOI · PMC8748880
- Burn TN, Schröder J, Gandolfo LC, Osman M, Wainwright EN, Lam EYN, et al.. Antigen reactivity defines tissue-resident memory and exhausted T cells in tumors. . 2026. PMID 41461987 · DOI · PMC12764432
- Künzli M, Masopust D. CD4+ T cell memory. Nat Immunol. 2023. PMID 37156885 · DOI · PMC10343737
- Corrado M, Pearce EL. Targeting memory T cell metabolism to improve immunity. J Clin Invest. 2022. PMID 34981777 · DOI · PMC8718135
- Zheng MZM, Wakim LM. Tissue resident memory T cells in the respiratory tract. Mucosal Immunol. 2022. PMID 34671115 · DOI · PMC8526531
- Zhang H, Weyand CM, Goronzy JJ. Hallmarks of the aging T-cell system. FEBS J. 2021. PMID 33590946 · DOI · PMC8364928
- Christo SN, Park SL, Mueller SN, Mackay LK. The Multifaceted Role of Tissue-Resident Memory T Cells. Annu Rev Immunol. 2024. PMID 38941605 · DOI
- Sun DY, Hu YJ, Li X, Peng J, Dai ZJ, Wang S. Unlocking the full potential of memory T cells in adoptive T cell therapy for hematologic malignancies. Int Immunopharmacol. 2025. PMID 39608170 · DOI
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 2026-10-31.
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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.