Treatment with depleting CD4 monoclonal antibody results in a preferential loss of circulating naive T cells but does not affect IFN-gamma secreting TH1 cells in humans.

The neurotransmitter γ-aminobutyric acid (GABA) is known to affect the activation and function of immune cells. This study investigated the role of GABA transporter (GAT)-2 in the differentiation of type 1 helper T (Th1) cells. Naïve CD4+ T cells isolated from splenocytes of GAT-2 knockout (KO) and wild-type (WT) mice were cultured; Th1 cell differentiation was induced and transcriptome and bioinformatics analyses were carried out. We found that GAT-2 deficiency promoted the differentiation of naïve T cells into Th1 cells. RNA sequencing revealed 2984 differentially expressed genes including 1616 that were up-regulated and 1368 that were down-regulated in GAT-2 KO cells compared to WT cells, which were associated with 950 enriched Gene Ontology terms and 33 enriched Kyoto Encyclopedia of Genes and Genomes pathways. Notably, 4 signal transduction pathways (hypoxia-inducible factor [HIF]-1, Hippo, phospholipase D, and Janus kinase [JAK]/signal transducer and activator of transcription [STAT]) and one metabolic pathway (glycolysis/gluconeogenesis) were significantly enriched by GAT-2 deficiency, suggesting that these pathways mediate the effect of GABA on T cell differentiation. Our results provide evidence for the immunomodulatory function of GABA signaling in T cell-mediated immunity and can guide future studies on the etiology and management of autoimmune diseases.

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Limited expression of R5-tropic HIV-1 in CCR5-positive type 1–polarized T cells explained by their ability to produce RANTES, MIP-1α, and MIP-1β

Blood ◽

10.1182/blood.v95.4.1167.004k11_1167_1174 ◽

2000 ◽

Vol 95 (4) ◽

pp. 1167-1174 ◽

Cited By ~ 37

Author(s):

Francesco Annunziato ◽

Grazia Galli ◽

Filomena Nappi ◽

Lorenzo Cosmi ◽

Roberto Manetti ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Memory T Cells ◽

Receptor Expression ◽

Th2 Cells ◽

Th1 Cells ◽

Naive T Cells ◽

Naïve T Cells ◽

Viral Spread ◽

Hiv 1

Human T helper (Th) cells (Th1- or Th2-oriented memory T cells as well as Th1- or Th2-polarized naive T cells) were infected in vitro with an R5-tropic HIV-1 strain (BaL) and assessed for their profile of cytokine production, CCR5 receptor expression, and HIV-1 p24 antigen (p24 Ag) production. Higher p24 Ag production was found in CCR5-negative Th2-like memory T cells than in CCR5-positive Th1-like memory T cells. By contrast, p24 Ag production was higher in Th1-polarized activated naive T cells in the first 4 days after infection. However, p24 Ag production in Th1-polarized T cells became comparable or even lower than the production in Th2-polarized populations later in infection or when the cells were infected with HIV-1BaL after secondary stimulation. The higher levels of p24 Ag production by Th1-polarized naive T cells soon after infection reflected a higher virus entry, as assessed by the single round infection assay using the HIV–chloramphenicol acetyl transferase (HIV-CAT) R5-tropic virus that contains the envelope protein of HIV-1 YU2 strain. The limitation of viral spread in the Th1-polarized populations, despite the initial higher level of T-cell entry of R5-tropic strains, was due to the ability of Th1 cells to produce greater amounts of β-chemokines than Th2 cells. In fact, an inverse correlation was observed between Th1-polarized naive T cells and Th1-like memory-activated T cells in regards to p24 Ag production and the release of the following CCR5-binding chemokines: regulated on activation normal T expressed and secreted (RANTES), macrophage inflammatory protein–1 (MIP-1), and MIP-1β. Moreover, infection with the HIV-1BaL strain of Th1-polarized T cells in the presence of a mixture of anti-RANTES, anti–MIP-1, and anti–MIP-1β neutralizing antibodies resulted in a significant increase of HIV-1 expression. These findings suggest that Th1-type responses may favor CD4+ T-cell infection by R5-tropic HIV-1 strains, but HIV-1 spread in Th1 cells is limited by their ability to produce CCR5-binding chemokines.

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Cytokine transcriptional events during helper T cell subset differentiation.

Journal of Experimental Medicine ◽

10.1084/jem.184.2.397 ◽

1996 ◽

Vol 184 (2) ◽

pp. 397-406 ◽

Cited By ~ 117

Author(s):

J A Lederer ◽

V L Perez ◽

L DesRoches ◽

S M Kim ◽

A K Abbas ◽

...

Keyword(s):

T Cells ◽

Transcription Factors ◽

T Cell ◽

Cell Subset ◽

Cytokine Gene Expression ◽

Ifn Gamma ◽

Naive T Cells ◽

Naïve T Cells ◽

Th2 Differentiation

The molecular basis for changes in cytokine expression during T helper (Th) cell subset differentiation is not well understood. We have characterized transcriptional events related to cytokine gene expression in populations of naive T cell receptor-transgenic T cells as they are driven in vitro toward Th1 or Th2 phenotypes by interleukin (IL)-12 or IL-4 treatment, respectively. Quantitative reverse transcriptase-polymerase chain reaction analysis of cytokine transcripts indicates that interferon (IFN) gamma, IL-4, and IL-2 mRNA are expressed with distinct kinetics after naive T cells are stimulated with antigen and either IL-4 or IL-12. IFN-gamma mRNA appears as early as 6 h in IL-12-treated cultures, IL-4 appears only after 48 h in IL-4-treated cultures, and IL-2 is equivalently expressed in both types of cultures. Analyses were performed to determine if there were any differences in activation of IL-2 or IL-4 transcription factors that accompanied Th1 versus Th2 differentiation. These studies demonstrated that signal transducer and activator of transcription 6 (STAT6) binds to a sequence in the IL-4 promoter and that this STAT6-binding site can support IL-4-dependent transcription of a linked heterologous promoter. Prolonged activation of STAT6 is characteristic of populations undergoing Th2 differentiation. Furthermore, STAT6 is activated in an autocrine manner when differentiated Th2 populations are stimulated by antigen receptor ligation. Th1 populations derived from IL-12 plus antigen treatment of naive T cells remain responsive to IL-4 as indicated by induction of STAT6 and IL-4 mRNA. These data indicate that Th1 and Th2 differentiation represents the combination of different, apparently independently regulated transcriptional events. Furthermore, among transcription factors that bind to the IL-4 or IL-2 promoters, STAT6 is the one whose activation distinguishes Th2 versus Th1 development.

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B7 and interleukin 12 cooperate for proliferation and interferon gamma production by mouse T helper clones that are unresponsive to B7 costimulation.

Journal of Experimental Medicine ◽

10.1084/jem.180.1.223 ◽

1994 ◽

Vol 180 (1) ◽

pp. 223-231 ◽

Cited By ~ 235

Author(s):

E E Murphy ◽

G Terres ◽

S E Macatonia ◽

C S Hsieh ◽

J Mattson ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Interleukin 12 ◽

T Helper ◽

Ifn Gamma ◽

Naive T Cells ◽

Naïve T Cells ◽

Maximal Stimulation ◽

Costimulatory Signals ◽

Stimulation Of

We have previously shown that dendritic cells isolated after overnight culture, which can express B7 and are potent stimulators of naive T cell proliferation, are relatively poor at inducing the proliferation of a panel of murine T helper 1 (Th1) clones. Maximal stimulation of Th1 clones was achieved using unseparated splenic antigen presenting cells (APC). An explanation for these findings is provided in the present study where we show that FcR+ L cells transfected with B7 stimulate minimal proliferation of Th1 clones in response to anti-CD3 antibodies, in contrast to induction of significant proliferation of naive T cells. However, addition of interleukin 12 (IL-12) to cultures of Th1 cells stimulated with anti-CD3 and FcR+ B7 transfectants resulted in a very pronounced increase in proliferation and interferon gamma (IFN-gamma) production. Exogenous IL-12 did not affect the B7-induced proliferation of naive T cells. This showed that whereas costimulatory signals delivered via B7-CD28 interaction are sufficient to induce significant proliferation of naive T cells activated through occupancy of the T cell receptor, Th1 T cell clones require cooperative costimulation by B7 and IL-12. This costimulation was shown to be specific by inhibition of proliferation and IFN-gamma production using chimeric soluble cytolytic T lymphocyte-associated antigen 4-human IgG1Fc (CTLA4-Ig) and anti-IL-12 antibodies. Furthermore, the significant antigen specific proliferation and IFN-gamma production by Th1 clones observed when splenocytes were used as APC was almost completely abrogated using CTLA4-Ig and anti-IL-12 antibodies. Thus two costimulatory signals, B7 and IL-12, account for the ability of splenic APC to induce maximal stimulation of Th1 clones. IL-10 downregulates the expression of IL-12 by IFN-gamma-stimulated macrophages and this may account largely for t the ability of IL-10 to inhibit APC function of splenic and macrophage APC for the induction of Th1 cell proliferation and IFN-gamma production. Indeed we show that IL-12 can overcome the inhibitory effect of IL-10 for the APC-dependent induction of proliferation and IFN-gamma production by Th1 clones. These results suggest that proliferation by terminally differentiated Th1 clones, in contrast to naive T cells, requires stimulation via membrane-bound B7 and a cytokine, IL-12. It is possible that these signals may result in the activation of unresponsive T cells during an inflammatory response. IL-10, by its role in regulating such innate inflammatory responses, may thus help to maintain these T cells in an unresponsive state.

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