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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.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.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.

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Related in: MedlinePlus

Spectratype data.Raw CD4+ spectratype data (upper panel) forsubject 1 on days 70 (left) and 183 (right) post-transplantation.CD4+ TCRBV usage frequency for average over10 healthy controls (solid bars), and subject 1 (striped bars) onthe same two days. The raw spectratype profiles are not representedon a consistent scale. Assays that had no peaks above 500fluorescent units are routinely excluded from subsequent analysis.These are marked with an asterisk.
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pcbi-1000396-g002: Spectratype data.Raw CD4+ spectratype data (upper panel) forsubject 1 on days 70 (left) and 183 (right) post-transplantation.CD4+ TCRBV usage frequency for average over10 healthy controls (solid bars), and subject 1 (striped bars) onthe same two days. The raw spectratype profiles are not representedon a consistent scale. Assays that had no peaks above 500fluorescent units are routinely excluded from subsequent analysis.These are marked with an asterisk.

Mentions: Spectratype analysis provided information about CDR3 length diversity withineach functional TCRBV family. Briefly, CD4 T cells were isolated from theperipheral blood of subjects and controls. RNA was prepared and used forcomplementary DNA (cDNA) synthesis. The cDNA was used as a template for 23TCRBV-specific primer pairs covering 21 TCRBV families to amplify thecomplete CDR3 region by PCR [54]. Each PCRproduct, representing a different TCRBV family, was size separated bycapillary gel electrophoresis and the product lengths were identified usingthe GeneScan software (Applied Biosciences). Product length distributions ofa Gaussian-like profile correspond to a polyclonal T cell repertoire.Variations between spectratype histograms of DiGeorge subjects and those ofhealthy adult controls provide information about the diversification of theTCRBV repertoire over time following transplantation. The raw spectratypedensitograms and TCRBV family frequency comparisons taken at two timespost-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) forsubject 1 on days 70 (left) and 183 (right) post-transplantation.CD4+ TCRBV usage frequency for average over10 healthy controls (solid bars), and subject 1 (striped bars) onthe same two days. The raw spectratype profiles are not representedon a consistent scale. Assays that had no peaks above 500fluorescent units are routinely excluded from subsequent analysis.These are marked with an asterisk.
© Copyright Policy
Related In: Results  -  Collection

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

pcbi-1000396-g002: Spectratype data.Raw CD4+ spectratype data (upper panel) forsubject 1 on days 70 (left) and 183 (right) post-transplantation.CD4+ TCRBV usage frequency for average over10 healthy controls (solid bars), and subject 1 (striped bars) onthe same two days. The raw spectratype profiles are not representedon a consistent scale. Assays that had no peaks above 500fluorescent units are routinely excluded from subsequent analysis.These are marked with an asterisk.
Mentions: Spectratype analysis provided information about CDR3 length diversity withineach functional TCRBV family. Briefly, CD4 T cells were isolated from theperipheral blood of subjects and controls. RNA was prepared and used forcomplementary DNA (cDNA) synthesis. The cDNA was used as a template for 23TCRBV-specific primer pairs covering 21 TCRBV families to amplify thecomplete CDR3 region by PCR [54]. Each PCRproduct, representing a different TCRBV family, was size separated bycapillary gel electrophoresis and the product lengths were identified usingthe GeneScan software (Applied Biosciences). Product length distributions ofa Gaussian-like profile correspond to a polyclonal T cell repertoire.Variations between spectratype histograms of DiGeorge subjects and those ofhealthy adult controls provide information about the diversification of theTCRBV repertoire over time following transplantation. The raw spectratypedensitograms and TCRBV family frequency comparisons taken at two timespost-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.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.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