Table 2.

Metabolic analysis of T cells and CAR-T cells based on single-cell techniques

Type	Method	Cell types	Cell source	Main conclusion	References
Single-cell RNA-seq	10X Genomics	CAR-T cells	5 healthy donors	41BB CAR-T cells had increased markers associated with CD8 central memory T cells and favored fatty acid metabolism	[141]
	1. Bulk-seq 2. 10X Genomics	CAR-T cells	24 patients with LBCL, 137,326 residual cells	Heterogeneity of CAR T cell infusion products contributes to variation in efficacy and toxicity after axi-cel therapy	[171]
	scTCR/transcriptome by 10X Genomics	peripheral blood lymphocytes after TIL infusion	1 patient with metastatic colorectal cancer	After ACT, the TILs gene expression patterns changed, but IL7R, ITGB1, KLF2 and ZNF683 remained expressed in the persistent clonotypes, compared to the non-persistent clonotypes	[161]
Single-cell Proteome	1. CyTOF 2. MIBI-TOF	CD8 T cells	1. Tumor tissue (n = 6) and healthy adjacent tissue from the same patients (n = 6) 2. Unrelated healthy donor PBMCs (n = 5) and lymph node biopsies (n = 3)	1. Three check points were identified of metabolic switching of naive human CD8+ T cells 2. Single-cell metabolic regulome profiling(scMEP) metabolic states associated clearly with distinct immunological phenotypes	[148]
	Mass Cytometry	CD8 T cells CAR-T cells	1. Naive or LMV infected WT C57BL/6 mice 2. 2 advanced NHL patients receiving axi-cel therapy	A distinct metabolic state in early-activate T cells (most abundant 5 days post-infection) characterized by maximal expression of glycolytic and oxidative metabolic proteins	[150]
	Met-Flow	Human PBMCs	12 donors, 150,000 cells per leukocyte population	1. Metabolic remodeling occurs during T cell activation 2. T cell memory subsets show differential metabolic phenotypes; The TCM and TEM populations both expressed higher levels of ACAC, PRDX2, and CPT1A, in contrast to naive and TTEMRA subsets	[172]
Multiplexed single-cell approaches	Ins-seq	Monocytes and macrophages	7648 cells from MCA205 tumor-bearing mice	1. Arginase 1-expressing cells within tumor is a metabolic immune signature of suppressive activity 2.A novel group of Arg1 + Trem2 + regulatory myloid(Mreg) cells was found and cellular markers, metabolic activity and associated pathways were defined	[160]
	1. 10X Genomics 2. Compass	Pathogenic and non-pathogenic Th17 cells	C57BL/6 wild-type mice	1. Pathogenic Th17 maintain higher aerobic glycolysis and TCA activity, whereas non-pathogenic Th17 oxidize fatty acids to produce ATP 2. Th17 pathogenicity was associated with arginine and downstream polyamine metabolism with enhanced polyamine-related enzyme expression in pathogenic Th17 and suppressed levels in Treg cells	[173]
	1. scRNA-seq 2. Mass cytometry 3. scATAC-seq	Human PBMCs	1. Young/Aged healthy adults 2. Young/Aged COVID-19 patients 3. Young/Aged COVID-19 patients recovered	Immune cell landscape was reprogrammed with age and was characterized by T cell polarization from naive and memory cells to effector, cytotoxic, exhausted and regulatory cells, along with other immune cells	[163]