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T cell markers

Your guide to identifying and studying T cells.
Last edited Thu 25 Apr 2024

T cells are a type of white blood cell or lymphocyte that recognizes and targets pathogen-infected cells, or cancer cells, for clearance. T cells originate from hematopoietic stem cells in the bone marrow and precursors are shuttled to the thymus for final maturation. T cells are selective, so that they are tolerant to the body’s own cells (self-molecules) but remain highly sensitive to non-self pathogens. There are many subsets of T cells, each with important functions relating to the immune system. Immunophenotyping offers a way to identify and quantify the different populations of T cells within a sample, using antibodies to detect specific antigens expressed by these cells, which are known as markers.

Three subtypes that are commonly studied in T cell research include:

Killer T cells recognize antigens, released by the infecting agent that becomes bound to the host cell. Killer T cells are capable of identifying and interacting with diverse cell types and pathogens. The T cell receptor binds the foreign antigen triggering the release of cytotoxins into the infected cell leading to cell death.

Helper T cells facilitate the immune system in fighting infection. Th cells recognize and bind to a pathogenic antigen, leading to the release of soluble factors (cytokines) that signal to the rest of the immune system to launch a response. Th cells are classified into different subsets, including Th1 cells and Th2 cells. Th1 cells bind to phagocytic macrophages and dendritic cells. Th2 cells bind and activate B cells, required for antibody production and, thus, securing life-long immunity against certain bacterial or viral infections.

Regulatory T cells keep the immune system in check. They ensure that once an immune response has occurred it is shut down. This regulatory mechanism represses immune activity thus preventing an exaggerated immune response. Normally functioning Treg cells are critical for safeguarding against autoimmune disease.

The table below describes further classes of T cell and markers applicable to their study.

Cell

Function

Markers

Naïve T cell

Successfully differentiated and undergone central selection in the thymus.

CD3, CD62L, CD197

Killer CD8 T cell

See above

CD8, IFNγ, TNFα, EOMES

Helper CD4 T cell

See above

CD4, CD183, IFNγ, IL-2, IL-4, IL-12, IL-18, STAT4, STAT1, CD194

Th1 T cell

Assist in activating macrophages to combat pathogens and subvert their microbial avoidance strategies

CD3, CD4, CD28, CD4, CD45, IFNγ, TNFα, T-bet

Th2 T cell

Produce cytokines, capable of mediating strong antibody production, eosinophil activation, and the restraint of a few macrophage capacities, giving phagocyte-independent defensive reactions.

CD3, CD4, CD45, CD184, CD365, GATA3, IL-4

Th17 T cell

Involved in host defense against extracellular pathogens, especially at the mucosal and epithelial borders. Dysregulation has been strongly associated with the pathogenesis of various autoimmune diseases.

CD3, CD4, CD194, IL17A, TGFβ, IL-6

Follicular helper T cell

A specialized subset of CD4+ T cells that help B cells produce antibodies against foreign pathogens. Found in secondary lymphoid organs (SLOs), tonsil, spleen and lymph nodes.

CD3, CD4, CD185, CD183, IL-21

Regulatory T cell

See above

CD4, CD25, CD127, CD152, TGFβ, IL-10, IL-12, FoxP3, STAT5

Central memory T cells

Provide central immunosurveillance by draining peripheral tissue sites. They provide effective long-term protection and have a high proliferative potential. Interchange into effector memory T cells upon antigen reencounter.

CD3, CD62L, CD197

Effector memory T cell

Present in the blood and peripheral organs for immunosurveillance in the defense against pathogens.

CD45, CD44

CD3

CD3 is involved in activating cytotoxic T-cells and T-helper cells.

We recommend

CD4

Initiates the early phase of T-cell activation. May function as an important mediator of indirect neuronal damage in infectious and immune-mediated CNS diseases. 

We recommend

CD8

T cell signaling; cytotoxic T cell-antigen interactions.

We recommend

CD25

Alternative names:

Interleukin-2 receptor subunit alpha, IL2RA, TAC antigen, TCGFR

Receptor for IL2 in complex with CD122 and CD132. 

We recommend

CD28

Alternative names:

TP44

Costimulation of T-cells. Induces T-cell activation and survival, interleukin-2 production, T-helper type 2 cell development and clonal expansion.

We recommend

CD44

Alternative names:

Epican, HUTCH-I, LHR, PGP-1, ECMR-III, IN, INLU, MC56, MDU2, MIC4, MUTCH-1

Leukocyte rolling, homing and aggregation. Adhesion of leukocytes to endothelial cells, stromal cells, and the extracellular matrix. Important in epithelial cell adhesion (cell-cell and cell-matrix) to hyaluronate in basement membranes and maintaining the polar orientation of cells.

We recommend

CD45

Alternative names:

Leukocyte common antigen, L-CA, PTPRC

Critical for B- and T-cell receptor-mediated activation. Also required for thymic selection.

We recommend

CD62L

Alternative names:

L-selectin, SELL, LAM1, LECAM1, LYAM1, Leu-8

Leukocyte rolling and homing on activated endothelium.

We recommend

CD127

Alternative names:

IL7R

Receptor for IL7. Involved with T-cell homeostasis and function.

We recommend

CD152

Alternative names:

CTLA-4

Negative regulation of T-cell activation. Contributes to the maintenance of peripheral T-cell tolerance to self antigens. It exerts its major effects on T-cell immune responses via regulation of the cell cycle.

We recommend

CD183

Alternative names:

CXCR3, GPR9, MigR

Receptor for CXCL9, CXCL10 and CXCL11. Upon ligand binding, induces responses that are involved in leukocyte traffic, integrin activation, cytoskeletal changes and chemotactic migration. 

We recommend

CD184

Alternative names:

CXCR4, HM89, LESTR, WHIM

Involved in AKT signaling cascade, regulates cell migration, hematopoietic progenitor cell homing and acts as co-receptor with CD4 for HIV-1 cell entry. Receptor for CXCL12.

We recommend

CD185

Alternative names:

CXCR5, BLR1, MDR15

Binds B-cell chemoattractant BL. Involved in B-cell migration into B-cell follicles of spleen and Peyer patches.

We recommend

CD194

Alternative names:

CCR4

Receptor for MIP-1, RANTES, TARC, and MCP-1 to regulate cell trafficking of leukocytes. Co-receptor for HIV-2. 

We recommend

CD197

Alternative names:

CCR7, BLR2, CMKBR7

Activates B- and T- lymphocytes, controls migration of B-cells and memory T-cells to inflamed tissues, stimulates dendritic cell migration. 

We recommend

CD365

Alternative names:

HAVCR1, TIM-1

Receptor for hepatitis A virus and TiMD4. May be involved in the moderation of asthma and allergic diseases.

We recommend

IFNγ

Alternative names:

Interferon gamma

We recommend

TNFα

We recommend

EOMES

Alternative names:

Tbr2

We recommend

IL-2

We recommend

IL-4

We recommend

IL-6

We recommend

IL-10

Interleukin 10 (IL-10) is an anti-inflammatory cytokine that plays an essential role in maintaining mucosal homeostasis and preventing pro-inflammatory responses. Loss-of-function mutations in genes encoding IL-10 cytokine and IL-10 receptor have been linked to very early-onset IBD.

We recommend

References

View 1 reference for IL-10

IL-12

We recommend

IL17A

We recommend

IL-18

We recommend

Il-21

We recommend

STAT1

Transcription factor found in helper Th1 cells.

We recommend

STAT4

Transcription factor found in helper Th1 cells.

We recommend

STAT5

Transcription factor.

We recommend

T-bet

Alternative names:

Tbx21

We recommend

GATA3

We recommend

TGF-beta

Transforming growth factor-β (TGF-β) is an immune-suppressive cytokine produced by many cell types, including immune cells. TGF-β signaling regulates mucosal immune system reactions and is shown to be impaired in the intestines of patients with IBD.

We recommend

FoxP3

Transcription factor.

We recommend

References

IL-10

Neurath, M. F. Cytokines in inflammatory bowel disease Nature Rev Immunol 5 (14),329-342 (2014)