ORIGINAL RESEARCH article
Front. Immunol.
Sec. T Cell Biology
SA-β-Gal stratification reveals senescence-associated heterogeneity and differential cell death susceptibility in human CD8 effector T cells
- LG
Luis Garza-Martinez 1,2
- MA
Mark Apadeer 1
- NM
Nica Mariz-Aquino 1,2
- PS
Paolo Sebastian Turano 1,2
- EA
Elizabeth Akbulut 1
- DO
Dillon Oswald 1,2
- SS
Sukhwinder Singh 2
- PF
Patricia Fitzgerald-Bocarsly 1,2
1. Rutgers University School of Graduate Studies, Newark, United States
2. Rutgers New Jersey Medical School Department of Pathology Immunology and Laboratory Medicine, Newark, United States
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Abstract
Cellular senescence in human T cells remains incompletely defined, particularly with respect to how senescence-associated states influence susceptibility to cell death. Here, we used flow-cytometric SPiDER-based detection of senescence-associated β-galactosidase (SA-β-gal) activity to profile human CD8+ T cell subsets from young and old donors. Effector memory (CD8EM) and effector memory re-expressing CD45RA (CD8EMRA) cells displayed the greatest within-subset heterogeneity in SA-β-gal activity. For this reason, we stratified the effector subsets by the lowest (bottom 25%) and highest (top 25%) quartiles of SA-β-Gal signal. We found that these populations occupied distinct regions in UMAP projections and were reproducibly enriched in different FlowSOM metaclusters, indicating that SA-β-Gal activity captures structured phenotypic states within differentiated CD8+ T-cell compartments. These states differed in senescence-associated markers, including CD27, CD28, CD57, and CX3CR1, as well as granzyme-associated programs involving Gzm A, B and K, whereas chronological age had only a limited effect once subsets were analyzed separately. Functionally, nutrient-limited conditions unmasked marked differences in cell death susceptibility between these populations. Following PMA/ionomycin stimulation, SA-β-Gal high CD8EM and CD8EMRA cells underwent accelerated stimulation-induced cell death, showed increased caspase-3/7 activation, and exhibited lower post-treatment γH2AX signalrelative to SA-β-Gal low counterparts. In contrast, in the absence of stimulation-induced energetic demand, SA-β-Gal high cells displayed greater resistance to cell death. Together, SA-β-Gal stratification resolves structured heterogeneity within human CD8 effector T cells and supports a context-dependent model in which senescence-associated effector states become selectively vulnerable to stimulation-induced death under metabolic stress.
Summary
Keywords
CD8 T cell, Cell Death, Effector memory T cell, EMRA T cells;, Granzymes, nutrient limitation, senescence-associated beta-galactosidase (SAβGal), T-cell senescence
Received
01 September 2026
Accepted
02 October 2026
Copyright
© 2026 Garza-Martinez, Apadeer, Mariz-Aquino, Turano, Akbulut, Oswald, Singh and Fitzgerald-Bocarsly. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Patricia Fitzgerald-Bocarsly
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