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Sensory adaptation in naive peripheral CD4 T cells.

Smith K, Seddon B, Purbhoo MA, Zamoyska R, Fisher AG, Merkenschlager M - J. Exp. Med. (2001)

Bottom Line: Here we show that pMHC contact modulates the expression of CD5 by naive CD4 T cells in a process that requires the continued expression of p56(lck).Reduced CD5 levels in T cells deprived of pMHC contact are predictive of elevated Ca(2)+ responses to subsequent TCR engagement by anti-CD3 or nominal antigen.Adaptation to peripheral pMHC contact may be important for regulating naive CD4 T cell responsiveness.

View Article: PubMed Central - PubMed

Affiliation: Lymphocyte Development Group, MRC Clinical Sciences Centre, ICSM Hammersmith Hospital, London W12 0NN, UK.

ABSTRACT
T cell receptor interactions with peptide/major histocompatibility complex (pMHC) ligands control the selection of T cells in the thymus as well as their homeostasis in peripheral lymphoid organs. Here we show that pMHC contact modulates the expression of CD5 by naive CD4 T cells in a process that requires the continued expression of p56(lck). Reduced CD5 levels in T cells deprived of pMHC contact are predictive of elevated Ca(2)+ responses to subsequent TCR engagement by anti-CD3 or nominal antigen. Adaptation to peripheral pMHC contact may be important for regulating naive CD4 T cell responsiveness.

Show MeSH
Loss of CD5 expression levels and basal tyrosine phosphorylation from naive CD4 LN cells maintained in vitro without TCR stimulation. Suspension cultures of APC-depleted Rag1o/o AND TCR transgenic LN cells (see Materials and Methods) were analyzed (A) for expression of TCR Vβ3 (the AND β chain) and CD5 by flow cytometry (histogram overlays are on a log scale and gated on CD4+ cells) and (B) for tyrosine phosphorylation status by Western blot analysis of total cell lysates with anti phosphotyrosine mAb. Note the decline of CD5 and tyrosine phosphorylation levels over time.
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fig1: Loss of CD5 expression levels and basal tyrosine phosphorylation from naive CD4 LN cells maintained in vitro without TCR stimulation. Suspension cultures of APC-depleted Rag1o/o AND TCR transgenic LN cells (see Materials and Methods) were analyzed (A) for expression of TCR Vβ3 (the AND β chain) and CD5 by flow cytometry (histogram overlays are on a log scale and gated on CD4+ cells) and (B) for tyrosine phosphorylation status by Western blot analysis of total cell lysates with anti phosphotyrosine mAb. Note the decline of CD5 and tyrosine phosphorylation levels over time.

Mentions: APC-depleted CD4 LN T cells from unprimed AND TCR transgenic mice (37) deficient in Rag1 (38) were employed as a near homogeneous population of naive peripheral T cells with uniform TCR specificity (37, 41). While CD5 expression increased dramatically when AND LN cells were cultured under conditions of TCR engagement (data not shown), CD5 levels declined to 50% or less of the ex vivo levels when these cells were cultured for 24 to 48 h in the absence of TCR stimulation. This downregulation was selective for CD5 since the expression of CD4 and TCR remained unchanged or increased slightly during the culture period (Fig. 1 A). CD5 downregulation was accompanied by a reduction of protein tyrosine phosphorylation relative to the level in resting T cells freshly isolated ex vivo, including p21 phospho-ζ (33, 44; Fig. 1 B).


Sensory adaptation in naive peripheral CD4 T cells.

Smith K, Seddon B, Purbhoo MA, Zamoyska R, Fisher AG, Merkenschlager M - J. Exp. Med. (2001)

Loss of CD5 expression levels and basal tyrosine phosphorylation from naive CD4 LN cells maintained in vitro without TCR stimulation. Suspension cultures of APC-depleted Rag1o/o AND TCR transgenic LN cells (see Materials and Methods) were analyzed (A) for expression of TCR Vβ3 (the AND β chain) and CD5 by flow cytometry (histogram overlays are on a log scale and gated on CD4+ cells) and (B) for tyrosine phosphorylation status by Western blot analysis of total cell lysates with anti phosphotyrosine mAb. Note the decline of CD5 and tyrosine phosphorylation levels over time.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2195983&req=5

fig1: Loss of CD5 expression levels and basal tyrosine phosphorylation from naive CD4 LN cells maintained in vitro without TCR stimulation. Suspension cultures of APC-depleted Rag1o/o AND TCR transgenic LN cells (see Materials and Methods) were analyzed (A) for expression of TCR Vβ3 (the AND β chain) and CD5 by flow cytometry (histogram overlays are on a log scale and gated on CD4+ cells) and (B) for tyrosine phosphorylation status by Western blot analysis of total cell lysates with anti phosphotyrosine mAb. Note the decline of CD5 and tyrosine phosphorylation levels over time.
Mentions: APC-depleted CD4 LN T cells from unprimed AND TCR transgenic mice (37) deficient in Rag1 (38) were employed as a near homogeneous population of naive peripheral T cells with uniform TCR specificity (37, 41). While CD5 expression increased dramatically when AND LN cells were cultured under conditions of TCR engagement (data not shown), CD5 levels declined to 50% or less of the ex vivo levels when these cells were cultured for 24 to 48 h in the absence of TCR stimulation. This downregulation was selective for CD5 since the expression of CD4 and TCR remained unchanged or increased slightly during the culture period (Fig. 1 A). CD5 downregulation was accompanied by a reduction of protein tyrosine phosphorylation relative to the level in resting T cells freshly isolated ex vivo, including p21 phospho-ζ (33, 44; Fig. 1 B).

Bottom Line: Here we show that pMHC contact modulates the expression of CD5 by naive CD4 T cells in a process that requires the continued expression of p56(lck).Reduced CD5 levels in T cells deprived of pMHC contact are predictive of elevated Ca(2)+ responses to subsequent TCR engagement by anti-CD3 or nominal antigen.Adaptation to peripheral pMHC contact may be important for regulating naive CD4 T cell responsiveness.

View Article: PubMed Central - PubMed

Affiliation: Lymphocyte Development Group, MRC Clinical Sciences Centre, ICSM Hammersmith Hospital, London W12 0NN, UK.

ABSTRACT
T cell receptor interactions with peptide/major histocompatibility complex (pMHC) ligands control the selection of T cells in the thymus as well as their homeostasis in peripheral lymphoid organs. Here we show that pMHC contact modulates the expression of CD5 by naive CD4 T cells in a process that requires the continued expression of p56(lck). Reduced CD5 levels in T cells deprived of pMHC contact are predictive of elevated Ca(2)+ responses to subsequent TCR engagement by anti-CD3 or nominal antigen. Adaptation to peripheral pMHC contact may be important for regulating naive CD4 T cell responsiveness.

Show MeSH