Limits...
The dynamics of T-cell receptor repertoire diversity following thymus transplantation for DiGeorge anomaly.

Ciupe SM, Devlin BH, Markert ML, Kepler TB - PLoS Comput. Biol. (2009)

Bottom Line: Although it has been demonstrated that disruption of either of these pathways has a profound effect on T-cell development, we do not yet have an understanding of the dynamical interactions of these pathways in their joint shaping of the T cell repertoire.Nevertheless, the diversity of the TCR repertoire depends crucially on TCR-specific regulation.The estimated strength of this TCR-specific regulation is sufficient to ensure rapid establishment of TCR repertoire diversity in the early phase of T cell population growth, and to maintain TCR repertoire diversity in the face of substantial clonal expansion-induced perturbation from the steady state.

View Article: PubMed Central - PubMed

Affiliation: Center for Computational Immunology, Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, North Carolina, USA.

ABSTRACT
T cell populations are regulated both by signals specific to the T-cell receptor (TCR) and by signals and resources, such as cytokines and space, that act independently of TCR specificity. Although it has been demonstrated that disruption of either of these pathways has a profound effect on T-cell development, we do not yet have an understanding of the dynamical interactions of these pathways in their joint shaping of the T cell repertoire. Complete DiGeorge Anomaly is a developmental abnormality that results in the failure of the thymus to develop, absence of T cells, and profound immune deficiency. After receiving thymic tissue grafts, patients suffering from DiGeorge anomaly develop T cells derived from their own precursors but matured in the donor tissue. We followed three DiGeorge patients after thymus transplantation to utilize the remarkable opportunity these subjects provide to elucidate human T-cell developmental regulation. Our goal is the determination of the respective roles of TCR-specific vs. TCR-nonspecific regulatory signals in the growth of these emerging T-cell populations. During the course of the study, we measured peripheral blood T-cell concentrations, TCRbeta V gene-segment usage and CDR3-length spectratypes over two years or more for each of the subjects. We find, through statistical analysis based on a novel stochastic population-dynamic T-cell model, that the carrying capacity corresponding to TCR-specific resources is approximately 1000-fold larger than that of TCR-nonspecific resources, implying that the size of the peripheral T-cell pool at steady state is determined almost entirely by TCR-nonspecific mechanisms. Nevertheless, the diversity of the TCR repertoire depends crucially on TCR-specific regulation. The estimated strength of this TCR-specific regulation is sufficient to ensure rapid establishment of TCR repertoire diversity in the early phase of T cell population growth, and to maintain TCR repertoire diversity in the face of substantial clonal expansion-induced perturbation from the steady state.

Show MeSH

Related in: MedlinePlus

Spectratype data.Raw CD4+ spectratype data (upper panel) for                                subject 1 on days 70 (left) and 183 (right) post-transplantation.                                    CD4+ TCRBV usage frequency for average over                                10 healthy controls (solid bars), and subject 1 (striped bars) on                                the same two days. The raw spectratype profiles are not represented                                on a consistent scale. Assays that had no peaks above 500                                fluorescent units are routinely excluded from subsequent analysis.                                These are marked with an asterisk.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2690399&req=5

pcbi-1000396-g002: Spectratype data.Raw CD4+ spectratype data (upper panel) for subject 1 on days 70 (left) and 183 (right) post-transplantation. CD4+ TCRBV usage frequency for average over 10 healthy controls (solid bars), and subject 1 (striped bars) on the same two days. The raw spectratype profiles are not represented on a consistent scale. Assays that had no peaks above 500 fluorescent units are routinely excluded from subsequent analysis. These are marked with an asterisk.

Mentions: Spectratype analysis provided information about CDR3 length diversity within each functional TCRBV family. Briefly, CD4 T cells were isolated from the peripheral blood of subjects and controls. RNA was prepared and used for complementary DNA (cDNA) synthesis. The cDNA was used as a template for 23 TCRBV-specific primer pairs covering 21 TCRBV families to amplify the complete CDR3 region by PCR [54]. Each PCR product, representing a different TCRBV family, was size separated by capillary gel electrophoresis and the product lengths were identified using the GeneScan software (Applied Biosciences). Product length distributions of a Gaussian-like profile correspond to a polyclonal T cell repertoire. Variations between spectratype histograms of DiGeorge subjects and those of healthy adult controls provide information about the diversification of the TCRBV repertoire over time following transplantation. The raw spectratype densitograms and TCRBV family frequency comparisons taken at two times post-transplantation from one subject are displayed in Figure 2.


The dynamics of T-cell receptor repertoire diversity following thymus transplantation for DiGeorge anomaly.

Ciupe SM, Devlin BH, Markert ML, Kepler TB - PLoS Comput. Biol. (2009)

Spectratype data.Raw CD4+ spectratype data (upper panel) for                                subject 1 on days 70 (left) and 183 (right) post-transplantation.                                    CD4+ TCRBV usage frequency for average over                                10 healthy controls (solid bars), and subject 1 (striped bars) on                                the same two days. The raw spectratype profiles are not represented                                on a consistent scale. Assays that had no peaks above 500                                fluorescent units are routinely excluded from subsequent analysis.                                These are marked with an asterisk.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2690399&req=5

pcbi-1000396-g002: Spectratype data.Raw CD4+ spectratype data (upper panel) for subject 1 on days 70 (left) and 183 (right) post-transplantation. CD4+ TCRBV usage frequency for average over 10 healthy controls (solid bars), and subject 1 (striped bars) on the same two days. The raw spectratype profiles are not represented on a consistent scale. Assays that had no peaks above 500 fluorescent units are routinely excluded from subsequent analysis. These are marked with an asterisk.
Mentions: Spectratype analysis provided information about CDR3 length diversity within each functional TCRBV family. Briefly, CD4 T cells were isolated from the peripheral blood of subjects and controls. RNA was prepared and used for complementary DNA (cDNA) synthesis. The cDNA was used as a template for 23 TCRBV-specific primer pairs covering 21 TCRBV families to amplify the complete CDR3 region by PCR [54]. Each PCR product, representing a different TCRBV family, was size separated by capillary gel electrophoresis and the product lengths were identified using the GeneScan software (Applied Biosciences). Product length distributions of a Gaussian-like profile correspond to a polyclonal T cell repertoire. Variations between spectratype histograms of DiGeorge subjects and those of healthy adult controls provide information about the diversification of the TCRBV repertoire over time following transplantation. The raw spectratype densitograms and TCRBV family frequency comparisons taken at two times post-transplantation from one subject are displayed in Figure 2.

Bottom Line: Although it has been demonstrated that disruption of either of these pathways has a profound effect on T-cell development, we do not yet have an understanding of the dynamical interactions of these pathways in their joint shaping of the T cell repertoire.Nevertheless, the diversity of the TCR repertoire depends crucially on TCR-specific regulation.The estimated strength of this TCR-specific regulation is sufficient to ensure rapid establishment of TCR repertoire diversity in the early phase of T cell population growth, and to maintain TCR repertoire diversity in the face of substantial clonal expansion-induced perturbation from the steady state.

View Article: PubMed Central - PubMed

Affiliation: Center for Computational Immunology, Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, North Carolina, USA.

ABSTRACT
T cell populations are regulated both by signals specific to the T-cell receptor (TCR) and by signals and resources, such as cytokines and space, that act independently of TCR specificity. Although it has been demonstrated that disruption of either of these pathways has a profound effect on T-cell development, we do not yet have an understanding of the dynamical interactions of these pathways in their joint shaping of the T cell repertoire. Complete DiGeorge Anomaly is a developmental abnormality that results in the failure of the thymus to develop, absence of T cells, and profound immune deficiency. After receiving thymic tissue grafts, patients suffering from DiGeorge anomaly develop T cells derived from their own precursors but matured in the donor tissue. We followed three DiGeorge patients after thymus transplantation to utilize the remarkable opportunity these subjects provide to elucidate human T-cell developmental regulation. Our goal is the determination of the respective roles of TCR-specific vs. TCR-nonspecific regulatory signals in the growth of these emerging T-cell populations. During the course of the study, we measured peripheral blood T-cell concentrations, TCRbeta V gene-segment usage and CDR3-length spectratypes over two years or more for each of the subjects. We find, through statistical analysis based on a novel stochastic population-dynamic T-cell model, that the carrying capacity corresponding to TCR-specific resources is approximately 1000-fold larger than that of TCR-nonspecific resources, implying that the size of the peripheral T-cell pool at steady state is determined almost entirely by TCR-nonspecific mechanisms. Nevertheless, the diversity of the TCR repertoire depends crucially on TCR-specific regulation. The estimated strength of this TCR-specific regulation is sufficient to ensure rapid establishment of TCR repertoire diversity in the early phase of T cell population growth, and to maintain TCR repertoire diversity in the face of substantial clonal expansion-induced perturbation from the steady state.

Show MeSH
Related in: MedlinePlus