Involvement of IL-2 in homeostasis of regulatory T cells: the IL-2 cycle.
A large body of evidence on the activity of regulatory T (Treg) cells was gathered during the last decade, and a similar number of reviews and opinion papers attempted to integrate the experimental findings. The abundant literature clearly delineates an exciting area of research but also underlines some major controversies. A linear cause-result interpretation of experimental maneuvers often ignores the fact that the activity of Treg cells is orchestrated with the effector T (Teff) cells within an intricate network of physiological immune homeostasis. Every modulation of the activity of the effector (cytotoxic) immune system revolves to affect the activity of regulatory (suppressive) cells through elaborate feedback loops of negative and positive regulation. The lack of IL-2 production by innate Treg cells makes this cytokine a prime coupler of the effector and suppressive mechanisms. Here we attempt to integrate evidence that delineates the involvement of IL-2 in primary and secondary feedback loops that regulate the activity of suppressive cells within the elaborate network of physiological immune homeostasis.
Yarkoni
Shai
S
Target-In Ltd, Petach Tikva, Israel.
Kaminitz
Ayelet
A
Sagiv
Yuval
Y
Yaniv
Isaac
I
Askenasy
Nadir
N
D000818:Animals; D006706:Homeostasis / Q000276:immunology*; D006801:Humans; D016753:Interleukin-10 / Q000276:immunology; D007376:Interleukin-2 / Q000276:immunology*; D053645:Interleukin-2 Receptor alpha Subunit / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D008822:Mice, Transgenic; D018448:Models, Immunological; D015375:Receptors, Interleukin-2 / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D016212:Transforming Growth Factor beta / Q000276:immunology
D007376:Interleukin-2; D053645:Interleukin-2 Receptor alpha Subunit; D015375:Receptors, Interleukin-2; D016212:Transforming Growth Factor beta; D016753:Interleukin-10