Virus-Specific CD8+ Stem Memory T Lymphocytes Display Enhanced Anti-Virus Responses

• Published in: Blood 2023-11, Vol.142 (Supplement 1), p.1181-1181
• Main Authors: Cao, Xunhong, Pei, Xuying, Shang, Qiannan, Zhao, Xiangyu, Huang, Xiaojun
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2023-188897

Virus specific memory CD8+ T cells can be divided into three subsets, stem memory (T SCM), central (T CM) and effector (T EM), but their lineage relationships and their ability to persist and confer protective immunity against virus infection are not well understood. Our results show that virus-specific CD8+T SCM have a greater capacity than T CM and T EM to persist in vivo and in vitro and are more efficient in mediating protective immunity against CMV infection and EBV infection because of their increased self-renew potential whether in transcriptome or in epigenome. We firstly expanded virus-specific T cells containing CD8+TSCM and CD8+TCM cells in vitro by stimulating healthy human PBMCs with cytokines and CMV (pp65 and IE1) and EBV (LMP2a and EBNA1) virus peptides. Then we fully evaluated the phenotypic and functional differences of diverse virus-specific memory T subsets and found that CD8+TSCM cells are a subset of low exhaustion, high migration and high secretion of IL-2. However, the expression of IFN-γand TNF-a and CD107a were lower compared with TEM cells, although comparable to CD8+TCM cells. We then evaluated the self-renewal and differentiation capacity of CD8+TSCM cells, compared with TCM or TEM cells. The results showed after stimulated with a-CD3/CD2/CD28 for 5 days, that CD8+TSCM cells possess around 50% of CD45RA+CD62L+ subpopulation cells. Meanwhile, CD8+TSCM cells constantly keep a higher expression of CD45RA+ cells than TCM and TEM cells in different proliferation generations. Notably, around 20% of TCM cells,5% of TEM cells and 10% of TEFF cells were found, suggesting that TSCM cells can reconstitute the whole memory T subsets. By contrast, the TCM cells mainly retained a central memory phenotype or differentiated into effector memory T cells and the TEM cells maintained its original phenotype. We also used the stem cell index to evaluate the stemness of different subgroups, and the results confirmed that the stemness evaluation of TSCM cells were significantly higher than TCM and TEM subsets. In vivo rein-fusion of different virus-specific T cell into irradidated NPG mice also showed that CD8+TSCM cells in vivo can differentiate into all memory T subsets in vivo while TCM cells mainly retained TEM and TCM subgroups at 4W post T cell infusion in mouse liver,lung and spleen(Figure 1A-G). To explore whether the antiviral ability of TSCM cells lasted longer than that of TCM and TEM cells. We first evaluated the apoptosis of different T