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Requirements for peptide-induced T cell receptor downregulation on naive CD8+ T cells.

Cai Z, Kishimoto H, Brunmark A, Jackson MR, Peterson PA, Sprent J - J. Exp. Med. (1997)

Bottom Line: These stringent requirements did not apply to TCR downregulation.Thus, TCR downregulation seemed to depend solely on TCR/peptide/interaction and did not require either CD8 or B7-1 expression; ICAM-1 potentiated TCR downregulation, but only with limiting doses of peptides.TCR downregulation was most prominent with high affinity peptides and appeared to be neither obligatory nor sufficient for T cell activation.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology, IMM4, The Scripps Research Institute, La Jolla, California 92037, USA.

ABSTRACT
The requirements for inducing downregulation of alpha/beta T cell receptor (TCR) molecules on naive major histocompatibility complex class I-restricted T cells was investigated with 2C TCR transgenic mice and defined peptides as antigen. Confirming previous results, activation of 2C T cells in response to specific peptides required CD8 expression on the responder cells and was heavily dependent upon costimulation provided by either B7-1 or ICAM-1 on antigen-presenting cells (APC). These stringent requirements did not apply to TCR downregulation. Thus, TCR downregulation seemed to depend solely on TCR/peptide/interaction and did not require either CD8 or B7-1 expression; ICAM-1 potentiated TCR downregulation, but only with limiting doses of peptides. TCR downregulation was most prominent with high affinity peptides and appeared to be neither obligatory nor sufficient for T cell activation. In marked contrast to T cell activation, TCR downregulation was resistant to various metabolic inhibitors. The biological significance of TCR downregulation is unclear, but could be a device for protecting T cells against excessive signaling.

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TCR and CD69 expression on CD8+ 2C cells stimulated by  spleen cells in the absence or presence of peptides. 5 × 105 CD8+ 2C  cells were cultured with 5 × 106 T-depleted B10.D2 (Ld+) or R103 (Ld−)  spleen cells in the presence or absence of p2Ca, QL9, SL9, or P1A peptides (10 μM) for the indicated time (12 h for C). The cells were harvested and stained with PE-conjugated anti-CD8 mAb and FITC-conjugated 1B2 mAb. TCR expression was analyzed by FACScan® gating on  CD8+ 2C cells. In B, the mean fluorescence intensity (MFI) of staining is  shown. The data in A, B a, B b, B c, and C are from five separate experiments.
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Figure 1: TCR and CD69 expression on CD8+ 2C cells stimulated by spleen cells in the absence or presence of peptides. 5 × 105 CD8+ 2C cells were cultured with 5 × 106 T-depleted B10.D2 (Ld+) or R103 (Ld−) spleen cells in the presence or absence of p2Ca, QL9, SL9, or P1A peptides (10 μM) for the indicated time (12 h for C). The cells were harvested and stained with PE-conjugated anti-CD8 mAb and FITC-conjugated 1B2 mAb. TCR expression was analyzed by FACScan® gating on CD8+ 2C cells. In B, the mean fluorescence intensity (MFI) of staining is shown. The data in A, B a, B b, B c, and C are from five separate experiments.

Mentions: To examine TCR expression, purified populations of naive phenotype (CD44lo) CD8+ cells were prepared from 2C LN and cultured in vitro with Ldpositive B10.D2 spleen cells or Ld-negative H-2 recombinant R103 (KdDbL−) spleen cells ± peptides for up to 3 d. The cells were then harvested, stained for the clonotypic 2C TCR (1B2), for CD69 and CD8 expression, and FACS® analyzed. The data in Fig. 1 show TCR and CD69 expression on gated CD8+ cells for cultures harvested after various periods. The data make two points.


Requirements for peptide-induced T cell receptor downregulation on naive CD8+ T cells.

Cai Z, Kishimoto H, Brunmark A, Jackson MR, Peterson PA, Sprent J - J. Exp. Med. (1997)

TCR and CD69 expression on CD8+ 2C cells stimulated by  spleen cells in the absence or presence of peptides. 5 × 105 CD8+ 2C  cells were cultured with 5 × 106 T-depleted B10.D2 (Ld+) or R103 (Ld−)  spleen cells in the presence or absence of p2Ca, QL9, SL9, or P1A peptides (10 μM) for the indicated time (12 h for C). The cells were harvested and stained with PE-conjugated anti-CD8 mAb and FITC-conjugated 1B2 mAb. TCR expression was analyzed by FACScan® gating on  CD8+ 2C cells. In B, the mean fluorescence intensity (MFI) of staining is  shown. The data in A, B a, B b, B c, and C are from five separate experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2196147&req=5

Figure 1: TCR and CD69 expression on CD8+ 2C cells stimulated by spleen cells in the absence or presence of peptides. 5 × 105 CD8+ 2C cells were cultured with 5 × 106 T-depleted B10.D2 (Ld+) or R103 (Ld−) spleen cells in the presence or absence of p2Ca, QL9, SL9, or P1A peptides (10 μM) for the indicated time (12 h for C). The cells were harvested and stained with PE-conjugated anti-CD8 mAb and FITC-conjugated 1B2 mAb. TCR expression was analyzed by FACScan® gating on CD8+ 2C cells. In B, the mean fluorescence intensity (MFI) of staining is shown. The data in A, B a, B b, B c, and C are from five separate experiments.
Mentions: To examine TCR expression, purified populations of naive phenotype (CD44lo) CD8+ cells were prepared from 2C LN and cultured in vitro with Ldpositive B10.D2 spleen cells or Ld-negative H-2 recombinant R103 (KdDbL−) spleen cells ± peptides for up to 3 d. The cells were then harvested, stained for the clonotypic 2C TCR (1B2), for CD69 and CD8 expression, and FACS® analyzed. The data in Fig. 1 show TCR and CD69 expression on gated CD8+ cells for cultures harvested after various periods. The data make two points.

Bottom Line: These stringent requirements did not apply to TCR downregulation.Thus, TCR downregulation seemed to depend solely on TCR/peptide/interaction and did not require either CD8 or B7-1 expression; ICAM-1 potentiated TCR downregulation, but only with limiting doses of peptides.TCR downregulation was most prominent with high affinity peptides and appeared to be neither obligatory nor sufficient for T cell activation.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology, IMM4, The Scripps Research Institute, La Jolla, California 92037, USA.

ABSTRACT
The requirements for inducing downregulation of alpha/beta T cell receptor (TCR) molecules on naive major histocompatibility complex class I-restricted T cells was investigated with 2C TCR transgenic mice and defined peptides as antigen. Confirming previous results, activation of 2C T cells in response to specific peptides required CD8 expression on the responder cells and was heavily dependent upon costimulation provided by either B7-1 or ICAM-1 on antigen-presenting cells (APC). These stringent requirements did not apply to TCR downregulation. Thus, TCR downregulation seemed to depend solely on TCR/peptide/interaction and did not require either CD8 or B7-1 expression; ICAM-1 potentiated TCR downregulation, but only with limiting doses of peptides. TCR downregulation was most prominent with high affinity peptides and appeared to be neither obligatory nor sufficient for T cell activation. In marked contrast to T cell activation, TCR downregulation was resistant to various metabolic inhibitors. The biological significance of TCR downregulation is unclear, but could be a device for protecting T cells against excessive signaling.

Show MeSH
Related in: MedlinePlus