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Peripheral selection of T cell repertoires: the role of continuous thymus output.

Tanchot C, Rocha B - J. Exp. Med. (1997)

Bottom Line: We investigated the role of continuous thymus output in the shaping of mature T cell repertoires by studying in vivo the survival of a single clone of mature Rag2-deficient T cell receptor (TCR) transgenic cells at different stages of activation in the absence or presence of thymus export.This T cell renewal ensured both the efficiency of recall responses to antigens as memory T cells persisted independently of thymus output, and the capacity of the immune system to respond to new antigen stimulation as the naive T cell pool was continuously renewed.Our results also indicate that thymus export is required to control the number of self-reactive peripheral T cells that may invade the peripheral pools if thymus output fails.

View Article: PubMed Central - PubMed

Affiliation: U345 Institut National de la Sante et de la Recherche Medicale, Institut Necker, 156, 75730 Paris Cedex 15, France.

ABSTRACT
We investigated the role of continuous thymus output in the shaping of mature T cell repertoires by studying in vivo the survival of a single clone of mature Rag2-deficient T cell receptor (TCR) transgenic cells at different stages of activation in the absence or presence of thymus export. In the absence of thymus export, TCR-transgenic lymphocytes survived indefinitely in the peripheral pools. When new lymphocytes were produced in the thymus and migrated to the periphery, resident memory T cells were maintained in constant numbers, whereas naive and self-reactive T cells were replaced by recent thymus migrants. This T cell renewal ensured both the efficiency of recall responses to antigens as memory T cells persisted independently of thymus output, and the capacity of the immune system to respond to new antigen stimulation as the naive T cell pool was continuously renewed. Our results also indicate that thymus export is required to control the number of self-reactive peripheral T cells that may invade the peripheral pools if thymus output fails.

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Exponential decay of four T cell clones of different sizes, calculated according to the formula X(t) = X0 (1 − a)t. The clone size (y-axis) is shown on a linear scale (top) or a log scale (bottom). The life span of  each clone (the number of days required for all members of the clone to  disappear) was calculated as the time required for each decay curve to intercept the x-axis, i.e., to fall below one cell.
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Figure 5: Exponential decay of four T cell clones of different sizes, calculated according to the formula X(t) = X0 (1 − a)t. The clone size (y-axis) is shown on a linear scale (top) or a log scale (bottom). The life span of each clone (the number of days required for all members of the clone to disappear) was calculated as the time required for each decay curve to intercept the x-axis, i.e., to fall below one cell.

Mentions: Using a thymus output of 106/d, taking into account the size of the peripheral pool and applying the formula X(t) = X0 (1 − a)t, we represent the putative exponential decay of clones of different sizes in Fig. 5. The curves in the upper and lower graphs are the same; in the upper graph, the size of each clone (y-axis) is shown on a linear scale, and in the lower graph, in a log scale. To determine the life span of each clone (the time taken for all members of a clone to disappear) we calculated the time required for each decay curve to intercept the x-axis, i.e., to fall below the value of one cell.


Peripheral selection of T cell repertoires: the role of continuous thymus output.

Tanchot C, Rocha B - J. Exp. Med. (1997)

Exponential decay of four T cell clones of different sizes, calculated according to the formula X(t) = X0 (1 − a)t. The clone size (y-axis) is shown on a linear scale (top) or a log scale (bottom). The life span of  each clone (the number of days required for all members of the clone to  disappear) was calculated as the time required for each decay curve to intercept the x-axis, i.e., to fall below one cell.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2199066&req=5

Figure 5: Exponential decay of four T cell clones of different sizes, calculated according to the formula X(t) = X0 (1 − a)t. The clone size (y-axis) is shown on a linear scale (top) or a log scale (bottom). The life span of each clone (the number of days required for all members of the clone to disappear) was calculated as the time required for each decay curve to intercept the x-axis, i.e., to fall below one cell.
Mentions: Using a thymus output of 106/d, taking into account the size of the peripheral pool and applying the formula X(t) = X0 (1 − a)t, we represent the putative exponential decay of clones of different sizes in Fig. 5. The curves in the upper and lower graphs are the same; in the upper graph, the size of each clone (y-axis) is shown on a linear scale, and in the lower graph, in a log scale. To determine the life span of each clone (the time taken for all members of a clone to disappear) we calculated the time required for each decay curve to intercept the x-axis, i.e., to fall below the value of one cell.

Bottom Line: We investigated the role of continuous thymus output in the shaping of mature T cell repertoires by studying in vivo the survival of a single clone of mature Rag2-deficient T cell receptor (TCR) transgenic cells at different stages of activation in the absence or presence of thymus export.This T cell renewal ensured both the efficiency of recall responses to antigens as memory T cells persisted independently of thymus output, and the capacity of the immune system to respond to new antigen stimulation as the naive T cell pool was continuously renewed.Our results also indicate that thymus export is required to control the number of self-reactive peripheral T cells that may invade the peripheral pools if thymus output fails.

View Article: PubMed Central - PubMed

Affiliation: U345 Institut National de la Sante et de la Recherche Medicale, Institut Necker, 156, 75730 Paris Cedex 15, France.

ABSTRACT
We investigated the role of continuous thymus output in the shaping of mature T cell repertoires by studying in vivo the survival of a single clone of mature Rag2-deficient T cell receptor (TCR) transgenic cells at different stages of activation in the absence or presence of thymus export. In the absence of thymus export, TCR-transgenic lymphocytes survived indefinitely in the peripheral pools. When new lymphocytes were produced in the thymus and migrated to the periphery, resident memory T cells were maintained in constant numbers, whereas naive and self-reactive T cells were replaced by recent thymus migrants. This T cell renewal ensured both the efficiency of recall responses to antigens as memory T cells persisted independently of thymus output, and the capacity of the immune system to respond to new antigen stimulation as the naive T cell pool was continuously renewed. Our results also indicate that thymus export is required to control the number of self-reactive peripheral T cells that may invade the peripheral pools if thymus output fails.

Show MeSH
Related in: MedlinePlus