T-cell receptor repertoire and function in umbilical cord blood lymphocytes from newborns of type 1 diabetic mothers

Abstract Recent observations show that the development of the human fetal immune system is susceptible to conditions of the maternal immune system and vice versa. To investigate the impact of type 1 diabetes mellitus in pregnant women on the maturation of the immune system of their newborn infants, the umbilical cord blood (UCB) T-cell repertoire at birth was analysed for clonal or oligoclonal expansions and TCRBV gene usage. Quantitative PCR using TCRBV family-specific probes and the spectratyping method were used. The extent of oligoclonal expansions observed in cord blood was markedly lower than in peripheral blood of the diabetic mothers and healthy adults. Functional analysis revealed that UCB T cells from newborns of both type 1 diabetic and gestational diabetic mothers are mature and can be readily stimulated by superantigens and phytohemagglutinin in vitro. No significant differences of the clonal contingent and the TCRBV usage were found in newborns of type 1 diabetic mothers when compared to newborns of gestational diabetic mothers, independent from the presence or absence of islet autoantigens. Our findings indicate that the immune system of type 1 diabetic mothers has no major effects on the TCR repertoire of the newborn infants. In that respect, no evidence was found for superantigen-activated T cells, nor was chronic hyperglycaemia per se found to alter either T-cell repertoire or functional activity.     

Clonally expanded CD4+CD28null T cells in rheumatoid arthritis use distinct combinations of T cell receptor BV and BJ elements

Clonally expanded, autoreactive CD4(+)CD28(null) cells can be found in the peripheral blood of patients with rheumatoid arthritis and have been shown to be associated with severeextra-articular disease manifestations. We investigated the size of the CD4(+)CD28(null) compartment and the TCR beta chain repertoire of expanded CD4(+) clonotypes in 94 rheumatoid arthritis patients by complementarity-determining region 3 (CDR3) length analysis (spectratyping) in the BV6 and BV14 TCR families, with primers specific for three arbitrarily chosen beta chain joining elements (BJ1S2, BJ2S3 and BJ2S7). The spectratyping results showed a strong correlation of the size of the CD4(+)CD28(null) compartment with the detected number of BV14 clonotypes, whereas no association with BV6 oligoclonality was found. Only clones using the BV14-BJ1S2 and BV14-BJ2S3 combinations contributed to this correlation, however, whereas BV14-BJ2S7 clones did not. This preferential correlation implies a role for the TCR beta chain in stimulating clonal outgrowth and argues against the previously suggested superantigenic stimulation of in-vivo-expanded clones. Instead, since no evidence for shared antigen specificity could be detected, clonal expansion of T cells in rheumatoid arthritis might be influenced by the BJ elements because of changes in the flexibility of the protein backbone of the beta-chain.     

Evidence for the persistence of monoclonal expansions of CD8+ T cells following primary simian immunodeficiency virus infection

A longitudinal study of the CD8⁺ TCR variable (Vβ) chain repertoire was performed in rhesus macaques experimentally infected with simian immunodeficiency virus (SIV) using both TCR Vβ chain-specific monoclonal antibodies and TCR β chain CDR3 length analysis. Expansions of subpopulations of CD8⁺ T cells were detected during the acute phase of SIV infection. In all monkeys studied, monoclonal expansions persisted for at least 18 months and increasingly dominated the repertoire of CD8⁺ T cells expressing the relevant Vβ chain. This study shows that persistent CD8⁺ T cell expansions develop in response to a virus infection. This is important not only for our understanding of the T cell response to viruses but also for understanding the factors that determine the normal CD8⁺ TCR repertoire.     

T cell repertoire in DQ5-positive MuSK-positive myasthenia gravis patients

Myasthenia gravis (MG) is a prototypical antibody-mediated disease characterized by muscle weakness and fatigability. Serum antibodies to the acetylcholine receptor and muscle-specific tyrosine kinase receptor (MuSK) are found in about 85% and 8% of patients respectively. We have previously shown that more than 70% of MG patients with MuSK antibodies share the HLA DQ5 allele. The aim of the present study was to analyze the T cell receptor (TCR) repertoire specific for recombinant human MuSK protein. We used the CDR3 TRBV-TRBJ spectratyping (immunoscope) to analyze the T cell response to MuSK from 13 DQ5+ MuSK-MG patients and from 7 controls (six DQ5+ MuSK negative subjects and one DQ5− DQ3+ MuSK positive patient). DQ5+ MuSK-MG patients but not controls used a restricted set of TCR VJ rearrangements in response to MuSK stimulation. One semiprivate (TRBV29-TRBJ2.5) rearrangement was found in 5/13 patients, while 4 other semiprivate (one in TRBV28-TRBJ2.1 and in TRBV3-TRBJ1.2, and two in TRBV28-TRBJ1.2) rearrangements were differently shared by 4/13 patients each and were absent in controls. When we sequenced the TRBV29-TRBJ2.5 rearrangement, we obtained 26 different sequences of the expected 130 bp length from 117 samples of the 5 positive patients: two common motifs GXGQET/TEHQET were shared in 4 patients as semiprivate motifs. Thus, the MuSK-specific T-cell response appears to be restricted in DQ5+ MuSK-MG patients, with a semiprivate repertoire including a common motif of TRBV29. This oligoclonal restriction of T cells will allow the identification of immunodominant epitopes in the antigen, providing therefore new tools for diagnosis and targeted therapy.     

Oligoclonal T cell expansion in myelodysplastic syndrome: evidence for an autoimmune process

There is accumulating evidence that the marrow-failure of myelodysplastic syndrome (MDS) is immune-mediated. We studied patients with MDS to look for oligoclonal or clonal expansion in T cells indicative of an autoimmune process. We used a PCR-based technique (spectratyping) to characterize the T cell repertoire in MDS (n=15; 9 RA, 4 RARS, 2 RAEB) and compared results with age-matched healthy donors (n=20) and transfusion-dependent (TD) patients with hemoglobinopathy (n=5). We found a significantly higher number of skewed Vβ profiles in the MDS patients compared with controls. In peripheral blood T cells, 60/345 Vβ profiles examined were skewed in MDS patients compared with 3/115 Vβ profiles in TD controls (P<0.0001), and 58/460 Vβ profiles in age-matched controls (P=0.05). A study of Jβ region within the skewed Vβ profiles revealed preferential usage of Jβ 2.1 in MDS in contrast with a wide distribution over the entire Jβ spectrum in controls, consistent with non-random T cell clonal expansion in MDS. These findings provide further evidence that T cell mediated immune processes are a feature of MDS.     

TCR β链CDR3谱序与疾病研究概况及进展

近年来,T细胞受体（TCR）互补决定区（CDR）和机体的生理、病理关系研究取得了较大的进展,尤其是在超抗原作用的感染性疾病、自身免疫性疾病、肿瘤等疾病状态下,TCRB链CDR3谱型能很好地反映T细胞的功能,通过TCRβ链CDR3谱型来研究克隆性和寡克隆性增生T细胞,可了解T细胞免疫与疾病发生发展的关系,指导疾病的诊断及免疫治疗,同时可了解正常情况下T细胞的发生和发展情况。     

Molecular analysis of T-cell repertoire in patients with graft-versus-host disease after allogeneic stem cell transplantation

Complementarity-determining region (CDR3) size spectratyping has often been used to analyze the clonal expansion of T-cells. CDR3 size spectratyping has been useful in the analysis of the oligoclonal expansion of T-cells in virus infection, graft-versus-leukemia effect (GVL), graft-versus-host disease (GVHD), and immune reconstitution of T-cells after allogeneic stem cell transplantation (allo-SCT). We analyzed 26 T cell receptor (TCR)-β-chain subfamilies (VB) in 25 patients who underwent allo-SCT. Fifteen of these patients developed acute GVHD (aGVHD). Many TCR-VB were skewed in the early stage. In these TCR-VB subfamilies, VB6 was most often skewed at the time of skin aGVHD. We then analyzed the average score of the complexity of 26 TCR-VB spectratypings in patients with or without cGVHD. The patients who developed chronic GVHD (cGVHD) had a lower average score of TCR-VB complexity than that of patients without cGVHD (P = 0.010). In particular, the patients who developed the quiescent type and de novo type of cGVHD from 4 months after allo- SCT had a lower average score of TCR-VB complexity at 3 months than that of the patients who had no cGVHD (P = 0.0055). These results suggest that we might be able to consider a possible development of cGVHD by analyzing TCR-VB spectratyping after allo-SCT.