Human Vgamma2Vdelta2 T cells contain cytoplasmic RANTES.
The adult human Vgamma2Vdelta2 T cell repertoire is a product of chronic selection in the periphery. Endogenous antigens drive the expansion of cells expressing the Vgamma2Vdelta2 TCR. Thus, we would expect the majority of circulating Vgamma2Vdelta2 T cells to be antigen experienced and to have memory phenotype, in contrast to the alpha/beta TCR+ subsets that include a substantial fraction of naive cells. We sought to characterize functional aspects of Vgamma2Vdelta2 T cells that might show whether circulating cells are memory or naive. For these studies, we focus on the expression of the CC chemokine regulated upon activation normal T cell expressed and secreted (RANTES). In naive alphabeta T cells, an initial stimulus triggers the onset of RANTES transcription followed later by protein expression. In memory CD8+ alphabeta T cells, RANTES mRNA is already present in unstimulated cells and protein expression is triggered immediately by TCR signaling; some cells may also contain RANTES protein in cytoplasmic stores. We show here that the vast majority of circulating human T cells contain RANTES protein in cytoplasmic stores and the chemokine is secreted rapidly after TCR signaling. Primary Vgamma2Vdelta2 T cell lines obtained after in vitro stimulation with phosphoantigens behaved similarly to circulating Vgamma2Vdelta2 T cells and contained both RANTES mRNA and protein, but only very low levels of mRNA or protein for macrophage inflammatory protein (MIP)-1alpha or MIP-1beta. The presence of stored RANTES shows that circulating Vgamma2Vdelta2 T cells are mostly memory phenotype and capable of rapid chemokine responses to phosphoantigen stimulation. Considering that one of 40 circulating CD3+ lymphocytes is Vgamma2Vdelta2+, they comprise the largest circulating memory population against a single antigen, and phosphoantigen stimulation will trigger a rapid activation with immediate release of RANTES.
Tikhonov
I
I
Institute of Human Virology, University of Maryland Biotechnology Institute, 725 West Lombard Street, Room N546, Baltimore, 21201, USA.
Deetz
C O
CO
Paca
R
R
Berg
S
S
Lukyanenko
V
V
Lim
J K
JK
Pauza
C D
CD
D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D018946:Chemokine CCL5 / Q000096:biosynthesis / Q000097:blood / Q000235:genetics / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation; D012333:RNA, Messenger / Q000096:biosynthesis / Q000097:blood / Q000235:genetics; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000097:blood / Q000276:immunology*
D018946:Chemokine CCL5; D012333:RNA, Messenger; D016692:Receptors, Antigen, T-Cell, gamma-delta