Table 1.

Treg Effector Molecules.

Effector Cell Type Ligand/Receptor Target Cell Mechanism
CTLA-4 Treg B7 molecules (CD80/CD86) DC Inhibition of DC activation through the trans-endocytosis and degradation of CD80 and CD86 molecules by Treg
Sterically hinders the association of naïve T cells with DC through co-ordinated activity with LFA-1
Negative regulation of effector T cell survival by signaling through Foxp3
IL-2 Activated T cells High-affinity IL-2 receptor Treg IL-2 deprivation by Treg in low-affinity TCR and antigen–MHC interactions induce T cell apoptosis
TIGIT Treg, T cells, NK cells CD155 (PVR), CD112 (PVRL2) DC Inhibition of IL-12 (p40) production by DCBinds CD155 (PVR) and CD112 (PVRL2) on APCs
Increases IL-10 expression inducing tolerogenic DC which suppress T cell proliferation and IFN-γ production
LAG-3 Treg MHC-II DC Inhibits DC maturation
Inhibits co-stimulation of naïve T cells by DC
CD39/CD73 Activated Treg Treg Activated T cells, DC CD39 converts ATP in the extracellular space into ADP and AMP, decreasing inflammation
CD39 increases suppressive activity of Treg
CD73 converts AMP to adenosine which inhibits DC function and activated T cells
IL-10 Treg IL-10R T cells, DC Inhibits T cell proliferation, decreases production of IL-2, TNF-α, and IL-5
Impairs Th1 responses by inhibiting DC activation and inhibiting secretion of IL-2
TGF-β Treg TGF-βR T cells Direct suppression of effector T cells
Inhibits cytokine production and cytotoxic function of T cells
IL-35 Treg IL-35R Naïve T cells, DC Direct inhibition of T cell proliferation
Induction of naïve T cells to become activated IL-35 Treg
Gzmb Treg Perforin-independent entry into target cell Activated T cells, DC Induction of apoptosis in target cells
FGL2 T cells, Treg, activated Treg FcγRIIB/RIII DC Inhibition of DC maturation
Suppression of Th1 and Th17 effector T cell responses

ADP, adenosine diphosphate; AMP, adenosine monophosphate; APC, antigen-presenting cell; ATP, adenosine triphosphate; CTLA-4, cytotoxic T lymphocyte-associated protein 4; DC, dendritic cell; FGL2, fibrinogen-like protein 2; Foxp3, forkhead box p3; Gzmb, granzyme B; IL, interleukin; LAG-3, lymphocyte activation gene 3; LFA-1, lymphocyte function-associated antigen 1; MHC, major histocompatibility complex; PVR, poliovirus receptor; PVRL, poliovirus receptor ligand; TCR, T cell receptor; TGF, transforming growth factor; TIGIT, T cell immunoreceptor with Ig and ITIM domains.

RMMJ Rambam Maimonides Medical Journal Rambam Health Care Campus 2015 July; 6(3): e0024. ISSN: 2076-9172
Published online 2015 July 30. doi: 10.5041/RMMJ.10209