Recently discovered T cell subsets cannot keep their commitments.
After activation by antigen/MHC (signal 1) and CD28-dependent co-stimulation (signal 2), resting CD4(+) T cells commit to one of a variety of functionally and molecularly defined phenotypes. Two long established CD4 phenotypes, Th1 and Th2 cells, have been regarded as terminally differentiated formats. Recently, two additional phenotypes, tissue-protective regulatory (Tregs) and tissue-destructive Th17 T cells, have also been discovered, and neither represents a terminally differentiated phenotype. Rather, Tregs and Th17(+) cells respond to cues provided by the inflammatory texture in which these cells reside. We review the important scientific and therapeutic implications of these differences herein.
Strom
Terry B
TB
Departments of Medicine and Surgery, Harvard Medical School, Transplant Institute, Division of Immunology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA. tstrom@bidmc.harvard.edu
Koulmanda
Maria
M
D000818:Animals; D006801:Humans; D007108:Immune Tolerance; D010641:Phenotype; D016176:T-Lymphocyte Subsets / Q000502:physiology*; D006377:T-Lymphocytes, Helper-Inducer / Q000502:physiology*; D050378:T-Lymphocytes, Regulatory / Q000502:physiology*