T Cell

Cytotoxic T cell
Surface
phenotype
αβ TCR, CD3, CD8
Transcription
factors
EOMES, T-bet, BLIMP1
Effector
molecules
secreted
Perforin, granzyme, IFNγ
Function Cytotoxic; kill infected and
transformed cells and thereby
protect the host from viral
infections and cancer. Direct
killing is mediated by secretion of
perforin and granzymes, which
cause apoptosis of target cells.
Otherfeatures
In humans, mainly CD45RO+. Some
terminally differentiated CTLs in
humans re-express CD45RA.

Exhausted T cell
Surface
phenotype
CD3, CD8, PD1,
TIM3, 1B11, LAG3
Transcription
factors
BLIMP1
Function Generated in response
to chronic antigenmediated
TCR
stimulation. These
cells express inhibitory
receptors and lack
effector cytokine
production; they
therefore fail tomount
effective antiviral
immune responses.

Anergic T cell
Surface
phenotype
αβ TCR, CD3, BTLA
Effector
factors
GRAIL, CBL-B, ITCH, NEDD4
Function These cells are generated
following TCR activation in
the absence of co-stimulatory
signals, which leads them
to become unresponsive to
subsequent stimulatory signals.
They are functionally inactive
cells and fail to proliferate orproduce IL-2. Their generation
may be important for avoiding
autoimmune responses.
Other
features
Increased expression of p27KIP1,
which leads to cell cycle arrest.

TR1 cell
Surface
phenotype
αβ TCR, CD3, CD4
Transcription
factors
Not known
Effector
molecules
secreted
IL-10
Function Immunosuppression
mediated by IL-10
production. These cells
are generated from naive
T cells inthe presence of
TGFβ and IL-27 or in the
presence of the immunosuppressive
drugs
vitamin D3 and
dexamethasone.

Natural TReg cell
Surface phenotype αβ TCR, CD3, CD4, CD25, CTLA4, GITR
Transcription factors FOXP3, STAT5, FOXO1, FOXO3
Effector molecules secreted IL-10, TGFβ, IL-35
Function Mediate immunosuppression and tolerogenic responses
through contact-dependent and -independentmechanisms. These cells are generated in the thymus.

Inducible TReg cell
Surface phenotype αβ TCR, CD3, CD4, CD25, CTLA4, GITR
Transcription factors FOXP3, FOXO1, FOXO3, STAT5, SMAD2, SMAD3, SMAD4
Effector molecules secreted IL-10, TGFβ
Function Promote immunosuppression and tolerance by
contact-dependent and -independent mechanisms.
These cells are generated from naive T cells in theperiphery and, at least in some cases, TGFβ and IL-2
are important for their differentiation.

NKT cell
Surface phenotype NK1.1, SLAMF1, SLAMF6, TGFβR,
Vα14, Jα18 (mouse)
Vα24, Jα18 (human)
Transcription
factors
PLZF
Effector molecules
secreted
IL-4, IFNγ, IL-17A
Function Can have both pro- and anti-inflammatory
functions. Have been shown to modulate immune
responses in several differentsettings, including
cancer, autoimmunity, allergy, infection and graftversus-
host disease.
Other features SAP expression. CD1-restricted TCR.
MAIT cells express an invariant TCR α-chain
(Vα33Jα19 in mice; Vα7.2Jα19 in humans).
MAIT cells are MR1 restricted (not CD1 restricted)
but have similarities to NKT cells.

CD8αα T cell
Surface
phenotype
αβ or γδ TCR, CD3,
CD8αα, B220
Effectormolecules
secreted
IL-10, TGFβ
Function Intraepithelial lymphocytes
are found in the gut. They can
develop intra- or extrathymically.
They express αβ or
γδ TCRs. γδ TCR+ cells express
KGF, whereas αβ TCR+ cells do
not. Most αβ TCRs are
enriched for self-reactivity.
They require β2 microglobulindependent
MHC class I
expression for their generation
and/or homeostasis. They can
haveregulatory functions
through the production of
IL-10 and TGFβ.
CD4+ αβ T cell
Surface phenotype αβ TCR, CD3, CD4, CCR7, CD62Lhi, IL-7R (CD127)
Transcription
factors
THPOK
Function Patrol through lymph nodes scanning peptide–
MHC class II molecule complexes on APCs for
the presence of their cognate antigen. Following
activation by APCs, naive CD4+ T cells
differentiate into effector...