T-cell Receptor Complementarity Determining Region 3 Research Articles

Chemical complementarity of tumor resident, T-cell receptor CDR3s and renalase-1 correlates with increased melanoma survival.

Overexpression of the secretory protein renalase-1 negatively impacts the survival of melanoma and pancreatic cancer patients, while inhibition of renalase-1 signaling drives tumor rejection by promoting T-cell activation. Thus, we investigated the chemical complementarity between melanoma-resident, T-cell receptor (TCR) complementarity-determining region 3 (CDR3) amino acid sequences (AAs) and the renalase-1 protein. Increasing complementarity of TCR CDR3s to renalase-1 AAs, as assessed by a chemical complementarity scoring algorithm, was associated with improved overall survival (OS) in melanoma patients. The expression levels of several immune signature genes were significantly, positively correlated with increasing TCR CDR3-renalase-1 complementarity scores. Additionally, the survival association observed with high complementarity of TCR CDR3s to renalase-1 AAs was more robust in cases with low renalase-1 gene expression levels. Mapping of TCR CDR3-renalase-1 in silico interaction sites identified major epitope candidates including RP220, the signaling module of the renalase-1 protein, consistent with the fact that a monoclonal antibody to RP220 is a potent inhibitor of melanoma growth. These findings indicate that renalase-1 is a potential antigen for TCR recognition in melanoma and could be considered as a target for immunotherapy.

Chemical Complementarity of Breast Cancer Resident, T-Cell Receptor CDR3 Domains and the Cancer Antigen, ARMC3, is Associated With Higher Levels of Survival and Granzyme Expression

Introduction: One of the most pressing goals for cancer immunotherapy at this time is the identification of actionable antigens. Methods: This study relies on the following considerations and approaches to identify potential breast cancer antigens: (i) the significant role of the adaptive immune receptor, complementarity determining region-3 (CDR3) in antigen binding, and the existence cancer testis antigens (CTAs); (ii) chemical attractiveness; and (iii) informing the relevance of the integration of items (i) and (ii) with patient outcome and tumor gene expression data. Results: We have assessed CTAs for associations with survival, based on their chemical complementarity with tumor resident T-cell receptor (TCR), CDR3s. Also, we have established gene expression correlations with the high TCR CDR3-CTA chemical complementarities, for Granzyme B, and other immune biomarkers. Conclusions: Overall, for several independent TCR CDR3 breast cancer datasets, the CTA, ARMC3, stood out as a completely novel, candidate antigen based on multiple algorithms with highly consistent approaches. This conclusion was facilitated by use of the recently constructed Adaptive Match web tool.

Delineation of a T-cell receptor CDR3-cancer mutanome aromaticity factor, assessable via blood samples, that facilitates the establishment of survival distinctions in bladder cancer.

A very large and still expanding collection of adaptive immune receptor (IR) recombination reads, representing many diseases, is becoming available for downstream analyses. Among the most productive approaches has been to establish risk stratification parameters via the chemical features of the IR complementarity determining region-3 (CDR3) amino acid (AA) sequences, particularly for large datasets where clinical information is available. Because the IR CDR3 AA sequences often play a large role in antigen binding, the chemistry of these AAs has the likelihood of representing a disease-related fingerprint as well as providing pre-screening information for candidate antigens. To approach this issue in a novel manner, we developed a bladder cancer, case evaluation approach based on CDR3 aromaticity. We developed and applied a simple and efficient algorithm for assessing aromatic, chemical complementarity between T-cell receptor (TCR) CDR3 AA sequences and the cancer specimen mutanome. Results indicated a survival distinction for aromatic CDR3-aromatic mutanome complementary, versus non-complementary, bladder cancer case sets. This result applied to both tumor resident and blood TCR CDR3 AA sequences and was supported by CDR3 AA sequences represented by both exome and RNAseq files. The described aromaticity factor algorithm has the potential of assisting in prognostic assessments and guiding immunotherapies for bladder cancer.

Chemical complementarity between tumor resident, T-cell receptor CDR3s and MAGEA3/6 correlates with increased melanoma survival: Potential relevance to MAGE vaccine auto-reactivity

Cancer testis antigens have been of interest as possible targets for cancer immunotherapies. To better understand the opportunities for the use of such immunotherapy targets, we used a chemical complementarity scoring algorithm and an original web tool to establish aspects of electrostatic complementarity of the CTAs, MAGEA3 and MAGEA6, with melanoma specimen resident, T-cell receptor (TCR) complementarity determining region 3 (CDR3) amino acid sequences. Greater electrostatic complementarity between T-cell receptor CDR3 and tumor CTAs MAGEA3/6 was associated with a greater probability of overall survival, for both the cancer genome atlas and Moffitt Cancer Center samples; and was associated with high levels of T-cell cytotoxicity-related gene expression. Most importantly, this approach allowed for the highly efficient screening of specific segments of the MAGEA3/6 antigens which indicated that certain MAGE segments would have either more or less risk of auto-reactivity. In sum, the chemical complementarity algorithm, and its efficient application via the web tool, adaptivematch.com, offers a convenient opportunity to identify likely parameters important for immunotherapy considerations and melanoma patient risk stratifications.

High-throughput, sliding-window algorithm for assessing chemical complementarity between immune receptor CDR3 domains and cancer mutant peptides: TRG-PIK3CA interactions and breast cancer

Physicochemical assessments of a vast accumulation of adaptive immune receptor (IR) recombinations have led to correlations of those properties with sub-divisions of various diseases. In the cancer setting, such assessments, particularly for the complementarity determining region-3 (CDR3) immune receptor domain, have been used to establish chemical complementarity matches to mutant amino acids (AA). These matches, in some cases, over very large numbers of tumor samples, have correlated with survival and gene expression distinctions. For example, in melanoma, electrostatic charge based, T-cell receptor CDR3-DNAH9 mutant AA complementarity represents better survival over multiple datasets that represent tumor tissue, T-cell receptor CDR3s. In this report, the complementarity approach has been expanded to include a more comprehensive representation of the interaction of T-cell receptor CDR3s and mutant AAs by incorporating the impact of the wild-type AAs surrounding the mutant AA. This “sliding window” approach was benchmarked against two large datasets of empirically determined CDR3-epitope pairs; showed more significant patient subdivisions; revealed a novel, TRG CDR3-mutant PIK3CA linkage in breast cancer; and was particularly suited to use with big data collections using only modest and widely-available processors. Thus, the algorithm should support more rapid and convenient indications (or prescreens) of CDR3-mutant peptide interactions for more focused studies and more efficient development of patient immunology-related prognostic tools and therapies.

Ultra-efficient sequencing of T Cell receptor repertoires reveals shared responses in muscle from patients with Myositis.

BackgroundMyositis, or idiopathic inflammatory myopathy (IIM), is a group disorders of unknown etiology characterized by the inflammation of skeletal muscle. The role of T cells and their antigenic targets in IIM initiation and progression is poorly understood. T cell receptor (TCR) repertoire sequencing is a powerful approach for characterizing complex T cell responses. However, current TCR sequencing methodologies are complex, expensive, or both, greatly limiting the scale of feasible studies.MethodsHere we present Framework Region 3 AmplifiKation sequencing (“FR3AK-seq”), a simplified multiplex PCR-based approach for the ultra-efficient and quantitative analysis of TCR complementarity determining region 3 (CDR3) repertoires. By using minimal primer sets targeting a conserved region immediately upstream of CDR3, undistorted amplicons are analyzed via short read, single-end sequencing. We also introduce the novel algorithm Inferring Sequences via Efficiency Projection and Primer Incorporation (“ISEPPI”) for linking CDR3s to their associated variable genes.FindingsWe find that FR3AK-seq is sensitive and quantitative, performing comparably to two different industry standards. FR3AK-seq and ISEPPI were used to efficiently and inexpensively characterize the T cell infiltrates of surgical muscle biopsies obtained from 145 patients with IIM and controls. A cluster of closely related TCRs was identified in samples from patients with sporadic inclusion body myositis (IBM).InterpretationThe ease and minimal cost of FR3AK-seq removes critical barriers to routine, large-scale TCR CDR3 repertoire analyses, thereby democratizing the quantitative assessment of human TCR repertoires in disease-relevant target tissues. Importantly, discovery of closely related TCRs in muscle from patients with IBM provides evidence for a shared antigen-driven T cell response in this disease of unknown pathogenesis.FundingThis work was supported by NIH grant U24AI118633 and a Prostate Cancer Foundation Young Investigator Award.

Abstract 4980: T-cell receptor clonotyping and immune infiltrate quantification with whole transcriptome RNA-seq from FFPE

Abstract Background: Even within patients with high tumor mutational burden (TMB) and/or PD-L1 expression, objective response rates to checkpoint therapies remain below 50% (e.g. Checkmate 227). Identifying predictive biomarkers for immune checkpoint inhibition therapy is an active area of research. Tumor infiltrating lymphocytes (TILs) show potential as a predictive biomarker for immune-oncology therapies. Rearrangement of the T-cell receptor (TCR) complementarity-determining region 3 (CDR3) serves as a marker for T-cell clones, and can be detected by RNA-seq of the region. The standard mechanism of tissue storage, formalin fixation and paraffin embedding (FFPE), degrades nucleic acids and makes sequencing more challenging. We present detection of TCR CDR3 of TILs from FFPE RNA-seq as a potential biomarker. Methods: FFPE Tumors from 65 head and neck squamous cell cancer (HNSCC), 233 colorectal carcinoma (CRC), and 217 non-small cell lung cancer (NSCLC) patients were profiled using deep full-transcriptome RNA-seq. Patients were assigned a TCR score by first aligning RNA-seq reads to TCRα and TCRβ CDR3 sequences, then counting overall CDR3 read support. Gene expression profiles were also used to predict consensus molecular subtype (CMS) and estimate immune cell abundance. To assess tumor sample purity, deep whole genome (N=244) or whole exome (N=271) DNA sequencing was performed on both tumor and normal blood samples from each patient. TMB was calculated directly by counting somatic non-synonymous exonic mutations. Results: Immune populations revealed high correlation (Pearson's r = .84, p = 3.6e-169) between TCR CDR3 counts and independent gene expression-based estimates of T-cell activity. Using the CMS of colon cancer samples, we found that CMS2 patients had a significantly lower average number of reads aligned to CDR3 (46.5 vs 91.6, p = 1.5e-7) which agrees with previous reports of low immune activity in that subtype. We compared CDR3 read count against TMB and found significant correlation (Spearman's rho = 0.34, p = 0.0048) in head and neck tumors where the median TMB was 98, but no association in lung or colon tumors where TMB is higher (median TMB 169 and 132 respectively). Finally, tumor purity estimated via DNA-seq was anti-correlated with CDR3 read count (Spearman's ρ = -0.39, p = 3.3e-21). Conclusions: TCR CDR3 read support from bulk RNA-seq on 515 solid tumor FFPE samples provides a related but distinct measure of T-cell infiltration to gene expression-based estimates. TMB and TCR support are generally independent biomarkers, especially in those tissues with higher average mutation rate. TCR support has potential to complement TMB as a predictive biomarker of immune checkpoint therapy response. Citation Format: Andrew J. Sedgewick, Jacob J. Adashek, Christopher W. Szeto, Charles J. Vaske, Philippe E. Spiess, Stephen C. Benz. T-cell receptor clonotyping and immune infiltrate quantification with whole transcriptome RNA-seq from FFPE [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4980.

The effects of CTX damage or inhibition of bone marrow hematopoiesis and GM-CSF stimulation of bone marrow hematopoiesis on the peripheral blood TCRβ CDR3 repertoire of BALB/c mice

Objective: This paper aims to investigate the dynamic changes of the T-cell receptor (TCR) β complementarity-determining region 3 (CDR3) repertoire during cyclophosphamide or Cytoxan (CTX) damage or inhibition of bone marrow hematopoiesis caused by a reduction of peripheral blood white blood cells (WBCs) in BALB/c mice.Methods: We analyze TCR CDR3 repertoire of BALB/c mice including (1) NS control group (2) CTX damage group (3) CTX damage + GM-CSF recovery group (4) CTX damage + auto-recovery group.Results: The number of WBCs in the CTX group is significantly lower than that in the NS group and after GM-CSF injection, the GM-CSF group is higher than that in the NS group. The diversity of the CTX damage group is the highest and there is a significant difference in high-frequency clonal proliferation between the CTX damage group and CTX damage + GM-CSF recovery group compared with the NS control group. In addition, the numbers of unique productive CDR3 overlapping numbers in the four experimental groups are similar.Conclusions: These data reveal that CTX significantly reduced the number of WBCs and ratio of high-frequency TCR CDR3 sequences, and indirectly increased the diversity of the TCR CDR3 repertoire. GM-CSF quickly restored the number of WBCs, and partially restored changes in the TCR CDR3 repertoire induced by CTX. Results from monitoring the dynamic changes of the TCR CDR3 repertoire can be used to assess the effects of CTX and GM-CSF on the function of peripheral blood T cells and to explore the possible underlying mechanisms.

A scoring system for the electrostatic complementarities of T-cell receptors and cancer-mutant amino acids: multi-cancer analyses of associated survival rates.

The anti-tumor immune response is considered to be due to the T-cell receptor (TCR) binding to tumor antigens, which can be either wild-type, early stem cell proteins, presumably foreign to a developed immune system; or mutant peptides, foreign to the immune system because of a mutant amino acid (aa) or otherwise somatically altered aa sequence. Recently, very large numbers of TCR complementarity-determining region-3 (CDR3) aa sequences obtained from tumor specimens have become available. We developed a novel algorithm for assessing the complementarity of tumor mutant peptides and TCR CDR3s, based on the retrieval of TCR CDR3 aa sequences from both tumor specimen and patient blood exomes and by using an automated process of assessing CDR3 and mutant aa electrical charges. Results indicated many instances where high electrostatic complementarity was associated with a higher survival rate. In particular, our approach led to the identification of specific genes contributing significantly to the complementary, TCR CDR3-mutant aa. These results suggest a novel approach to tumor immunoscoring and may lead to the identification of high-priority neo-antigen, peptide vaccines; or to the identification of ex vivo stimulants of tumor-infiltrating lymphocytes.

Determination of the complexity and diversity of the TCR β-chain CDR3 repertoire in bladder cancer using high-throughput sequencing.

The present study aimed to investigate the complexity and diversity of the T lymphocyte immune repertoire in patients with bladder cancer. To do so, the immune state of patients was assessed. The study also aimed to elucidate the aetiology and pathogenesis of bladder cancer to provide a novel theoretical basis for disease prevention, diagnosis, treatment and prognosis monitoring. Cancerous and paracancerous (control) tissue samples were collected from five patients diagnosed with muscle-invasive bladder cancer. Multiplex polymerase chain reaction and Illumina high-throughput sequencing were used to determine the characteristics and clonal diversity of the T-cell receptor (TCR) β-chain complementarity-determining region 3 (CDR3) gene in the cancerous and paracancerous tissues of patients with bladder cancer. The degree of clonal expansion in malignant samples was significantly higher than in adjacent samples. Furthermore, ΤCRβ variable (TRBV), ΤCRβ diversity (TRBD) and ΤCRβ joining (TRBJ) repertoires were significantly different in cancerous samples compared with adjacent samples. In addition, 13 identified V-J pairs were highly expressed in cancerous samples whereas they had low expression in control samples. In conclusion, the degree of T-cell clonal expansion in bladder cancerous tissue was higher than in paracancerous tissue, whereas the immune diversity of the tissues of patients with bladder cancer was significantly lower. The DNA sequence and amino acid sequences, and V-J combination level may be used to comprehensively understand the diversity and characteristics of TCR CDR3 in bladder cancer and paracancerous tissues, and to evaluate the immune status of bladder cancer to develop therapeutic targets and biomarkers for prognosis monitoring.

A comprehensive study of immunology repertoires in both preoperative stage and postoperative stage in patients with colorectal cancer.

BackgroundColorectal cancer (CRC) is the 3rd most common cancer type in the world. The correlation between immune repertoire and prognosis of CRC has been well studied in the last decades. The diversity and stability of the immune cells can be measured by hypervariable complementarity‐determining region 3 (CDR3) segments of the T‐cell receptor (TCR).MethodsIn this study, we collected five healthy controls and 19 CRC patients’ peripheral blood mononuclear cells (PBMCs) in three stages, namely 1 day preoperative, 3 days’ postoperative, and 7 days’ postoperative, respectively. Simultaneously, we have also done the comparative analysis of these two different anesthesia methods, namely TIVA and CEGA. Sequencing of the TCR segments has been performed by multiplex PCR and high‐throughput next‐generation sequencing. We also analyzed the distribution of CDR3 length, highly expansion clones (HECs), TRBV, and TRBJ gene usage.ResultsOur result showed a significant difference between TCR CDR3 length distribution and HEC distribution between CRC patients and healthy controls. We also found that TRBV11‐2, TRBV12‐1, TRBV16, TRBV3‐2, TRBV4‐2, TRBV4‐3, TRBV5‐4, TRBV6‐8, TRBV7‐8, TRBV7‐9 and RBV11‐2, TRBV12‐1, TRBV16, TRBV3‐2, TRBV4‐2, TRBV4‐3, TRBV5‐4, TRBV6‐8, TRBV7‐8, and TRBV7‐9 usages are different between CRC patients and healthy controls.ConclusionIn conclusion, CRC patients were presented with different immune repertoire in comparison with healthy controls. In this study, significant difference in TRBV and TRBJ gene usage in between case and control group could provide some potential biomarker for the diagnosis and the treatment of the patients with CRC.

Next generation sequencing reveals changes of the \u03b3\u03b4 T cell receptor repertoires in patients with pulmonary tuberculosis

Tuberculosis (TB) is a severe global threat to human health. The immune protection initiated by γδ T cells play an important role in mycobacterial infection. Vaccines for Mycobacterium tuberculosis (Mtb) based on γδ T cells provide a novel approach for TB control. In our previous studies, we found a preponderant complementarity-determining region 3 (CDR3) sequence of the γδ T cell receptor (TCR) in TB patients, and successfully identified a tuberculosis antigen that can effectively activate γδ T cells with a reverse genetic strategy. However, due to the throughput limitation of the method we used, the information we obtained about the γδ TCR repertoire and preponderant CDR3 sequences was limited. In this study, we introduced next generation sequencing (NGS) to study the γδ TCR CDR3 repertoires in TB patients. We found that the CDR3δ tended to be more polyclonal and CDR3γ tended to be longer in TB patients; the γδ T cells expressing CDR3 sequences using a Vγ9-JγP rearrangement expanded significantly during Mtb infection. We also identified new preponderant CDR3 sequences during Mtb infection. This study comprehensively characterized the γδ T cell receptor repertoire changes, and provides useful information for the development of new vaccines and adjuvants against TB.

Folliculotropic Mycosis Fungoides with Skewed T-cell Receptor CDR3 Motif: Suggestive of Lipid-antigen Selection?

Folliculotropic mycosis fungoides (FMF), a variant of mycosis fungoides (MF) with distinct clinical features, is characterized by infiltration of malignant T cells in hair follicles. This raises the hypothesis that antigens in the hair follicle may contribute to the pathogenesis of FMF.T-cell receptor β gene (TRB) sequences as well as dendritic cell subsets in patients with FMF (n = 21) and control patients with MF (n = 20) were studied to explore this hypothesis. A recurrent usage of the TRB junctional genes TRBJ2-1 and TRBJ2-7 was found in patients with FMF compared with those with MF. These genes contribute to an amino acid motif in the complementarity-determining region 3 (CDR3) of the T-cell receptor. This motif was previously found in T cells stimulated by lipids bound to CD1 on antigen-presenting cells. Additional immunohistochemical analysis revealed abundant CD1c- and CD1a- expressing dendritic cells in FMF. The combined findings support a role for lipid-antigen stimulation in FMF.

BCR CDR3 length distributions differ between blood and spleen and between old and young patients, and TCR distributions can be used to detect myelodysplastic syndrome

Complementarity-determining region 3 (CDR3) is the most hyper-variable region in B cell receptor (BCR) and T cell receptor (TCR) genes, and the most critical structure in antigen recognition and thereby in determining the fates of developing and responding lymphocytes. There are millions of different TCR Vβ chain or BCR heavy chain CDR3 sequences in human blood. Even now, when high-throughput sequencing becomes widely used, CDR3 length distributions (also called spectratypes) are still a much quicker and cheaper method of assessing repertoire diversity. However, distribution complexity and the large amount of information per sample (e.g. 32 distributions of the TCRα chain, and 24 of TCRβ) calls for the use of machine learning tools for full exploration. We have examined the ability of supervised machine learning, which uses computational models to find hidden patterns in predefined biological groups, to analyze CDR3 length distributions from various sources, and distinguish between experimental groups. We found that (a) splenic BCR CDR3 length distributions are characterized by low standard deviations and few local maxima, compared to peripheral blood distributions; (b) healthy elderly people's BCR CDR3 length distributions can be distinguished from those of the young; and (c) a machine learning model based on TCR CDR3 distribution features can detect myelodysplastic syndrome with approximately 93% accuracy. Overall, we demonstrate that using supervised machine learning methods can contribute to our understanding of lymphocyte repertoire diversity.

Dynamic monitoring the TCR CDR3 spectratypes in patients with metastatic CRC treated with a combination of bevacizumab, irinotecan, fluorouracil, and leucovorin.

In the present study, either modified IFL regimen (modified irinotecan, fluorouracil and leucovorin, mIFL) alone or in combination with bevacizumab was used to treat patients with metastatic colorectal cancer (CRC). Treatment efficacy was assessed using coupled tomography imaging diagnosis. The toxicity accompany with treatment was evaluated, as well as T cell receptor (TCR) repertoire before and several cycles after therapy was dynamically monitored by analyzing the complementarity-determining region 3 (CDR3) length distribution within CD4(+) and CD8(+) T cell subsets. The degrees of normalization of the T cell repertoire in CRC patients treated with the two methods were compared. The results showed that mIFL combined with bevacizumab was more effective in treating patients with metastatic CRC, and was accompanied by an increase in side effects such as proteinuria and hematuria. An even more restricted CDR3 profile in patients with metastatic CRC compared with healthy control has been detected. A prominent usage of TCR beta chain variable (BV) gene BV12 and BV16 families within the CD4(+) T cell subset and BV19 and BV21 families within the CD8(+) T cell subset have been found before treatment. Moreover, CD8(+) T cells showed more restricted patterns than CD4(+) T cells, especially in patients before treatment. For patients with stable disease (SD) or partial remission (PR) after treatment, a less restricted CDR3 profile in post-treatment compared with pre-treatment has been found, but the opposite result was observed for patients with progressive disease (PD). The less restricted CDR3 pattern suggested a trend toward normalization of the TCR repertoire. The normalization of TCR repertoire significantly increased in patients treated with mIFL in combination with bevacizumab, but slightly in patients treated with mIFL alone. The results demonstrate a positive correlation between post-therapy TCR repertoire normalization and remission of metastatic CRC.

399: Examining Human TCR CDR3 Diversity during Lymphopenia

Investigations of T cell receptor (TCR) repertoire diversity have contributed to our current understanding of the post-transplant effects on T cell populations of antigen-driven peripheral expansion and thymic-dependent immune reconstitution. Spectratyping, the RT-PCR based assessment of variation in the lengths of the complementarity determining region 3 (CDR3) of the TCR BV families, has been widely used to define oligoclonal, skewed and polyclonal Gaussian-like repertoire diversity. The limited levels of circulating T cells following transplantation have, however, limited the use of this technique on clinically available samples.

A novel approach for the analysis of T-cell reconstitution by using a T-cell receptor β-based oligonucleotide microarray in hematopoietic stem cell transplantation

Analysis of T-cell population diversity is important to hematopoietic stem cell transplantation (HSCT). The millions of specificities in T-cell receptor (TCR) hypervariable complementarity- determining region 3 (CDR3) precludes detection of all T-cell populations by antibody-based flow cytometry. An alternative method, the TCR CDR3 spectratyping assay, involves multiple polymerase chain reaction (PCR) analyses and is interpreted only qualitatively. In this study, we designed the first TCRbeeta-based oligonucleotide microarray and investigated its specificity, clonality discrimination, sensitivity of detection, and feasibility for monitoring T-cell population diversity in HSCT. The array contains 27 TCR Vbeta probes and 13 Jbeta probes. TCRbeta repertoire diversity was detected with single PCR, microarray hybridization system, and Spotfire analysis software. TCRO-based microarray provides specific sequence-based information and can distinguish T-cell monoclonal expansion within a polyclonal population. We successfully used this microarray to quantitatively and qualitatively analyze T-cell population diversity in recipients of hematopoietic stem cell transplants. This success suggests broad potential applications of the microarray for use in many other areas, including anti-tumor immunity, vaccination, autoimmunity, infectious diseases, and leukemia. By providing a single PCR-based assay to quantify multiple T-cell populations in parallel, this device will allow clinicians and researchers to rapidly perform high-throughput surveys.

T cell expansions in lymph nodes and peripheral blood in HIV-1-infected individuals: effect of antiretroviral therapy.

To evaluate dynamics in CD8 T cell expansions during highly active antiretroviral therapy (HAART). Various T cell subsets were isolated from blood and lymph nodes and analysed for T cell receptor (TCR) diversity. TCR complementarity determining region 3 (CDR3) spectratyping and single-strand conformation polymorphism (SSCP) analyses were performed in combination with sequencing to assess clonality of the subsets. Strongly skewed CDR3 patterns in total CD8 cells and the CD8 subsets CD45RO+CD27+ and CD45RO-CD27+ showed substantial dynamics in dominant CDR3 sizes, resulting in relative improvement of CDR3 size diversity in the first months of therapy. During sustained treatment, TCR diversity changed only moderately. SSCP profiles confirmed oligoclonality of TCR CDR3 perturbations. Various dominant CDR3 sizes for CD4 and CD8 T cells present in lymph nodes, but not in peripheral blood mononuclear cells, before the start of therapy emerged in peripheral blood early during therapy. HAART induces substantial changes in CD8 TCR diversity, eventually resulting in improvement of the repertoire. Clonal expansions observed in lymph nodes before therapy were observed in peripheral blood after therapy, suggesting that recirculation of CD4 and CD8 T cells from lymph nodes contributes to the early T cell repopulation. Decreased immune activation and possibly naive T cell regeneration subsequently decreased clonal expansions and perturbations in the CD8 TCR repertoire.

T-Cell Immune Reconstitution in Pediatric Leukemia Patients After Allogeneic Bone Marrow Transplantation With T-Cell–Depleted or Unmanipulated Grafts: Evaluation of Overall and Antigen-Specific T-Cell Repertoires

To evaluate the role of T-cell selection in the thymus and/or periphery in T-cell immune reconstitution after allogeneic bone marrow transplantation (allo-BMT), we have analyzed the overall and antigen-specific T-cell repertoires in pediatric allo-BMT recipients treated for leukemia. We observed a lack of overall T-cell receptor (TCR) diversity in the repopulating T cells at 3 months after allo-BMT, as was deduced from complementarity determining region 3 (CDR3) size distribution patterns displaying reduced complexity. This was noted particularly in recipients of a T-cell–depleted (TCD) graft and, to a lesser extent, also in recipients of unmanipulated grafts. At 1 year after allo-BMT, normalization was observed of TCR CDR3 size complexity in almost all recipients. Analysis of the antigen-specific T-cell repertoire at 1 year after BMT showed that the T cells responding to tetanus toxoid (TT) differed in TCR gene segment usage and in amino acid composition of the CDR3 region when comparing the recipient with the donor. Moreover, the TT-specific TCR repertoire was found to be stable within a given allo-BMT recipient, because TT-specific T cells with completely identical TCRs were found at 3 consecutive years after transplantation. These observations suggest an important role for T-cell selection processes in the complete restoration of the T-cell immune repertoire in children after allo-BMT.

T-Cell Immune Reconstitution in Pediatric Leukemia Patients After Allogeneic Bone Marrow Transplantation With T-Cell–Depleted or Unmanipulated Grafts: Evaluation of Overall and Antigen-Specific T-Cell Repertoires

AbstractTo evaluate the role of T-cell selection in the thymus and/or periphery in T-cell immune reconstitution after allogeneic bone marrow transplantation (allo-BMT), we have analyzed the overall and antigen-specific T-cell repertoires in pediatric allo-BMT recipients treated for leukemia. We observed a lack of overall T-cell receptor (TCR) diversity in the repopulating T cells at 3 months after allo-BMT, as was deduced from complementarity determining region 3 (CDR3) size distribution patterns displaying reduced complexity. This was noted particularly in recipients of a T-cell–depleted (TCD) graft and, to a lesser extent, also in recipients of unmanipulated grafts. At 1 year after allo-BMT, normalization was observed of TCR CDR3 size complexity in almost all recipients. Analysis of the antigen-specific T-cell repertoire at 1 year after BMT showed that the T cells responding to tetanus toxoid (TT) differed in TCR gene segment usage and in amino acid composition of the CDR3 region when comparing the recipient with the donor. Moreover, the TT-specific TCR repertoire was found to be stable within a given allo-BMT recipient, because TT-specific T cells with completely identical TCRs were found at 3 consecutive years after transplantation. These observations suggest an important role for T-cell selection processes in the complete restoration of the T-cell immune repertoire in children after allo-BMT.