Analysis of the CDR3 region of alpha/beta T-cell receptors (TCRs) and TCR BD gene double-stranded recombination signal sequence breaks end in peripheral blood mononuclear cells of T-lineage acute lymphoblastic leukemia

Recent Advances in Targeting CD8 T-Cell Immunity for More Effective Cancer Immunotherapy

Recent advances in cancer treatment have emerged from new immunotherapies targeting T-cell inhibitory receptors, including cytotoxic T-lymphocyte associated antigen (CTLA)-4 and programmed cell death (PD)-1. In this context, anti-CTLA-4 and anti-PD-1 monoclonal antibodies have demonstrated survival benefits in numerous cancers, including melanoma and non-small-cell lung carcinoma. PD-1-expressing CD8⁺ T lymphocytes appear to play a major role in the response to these immune checkpoint inhibitors (ICI). Cytotoxic T lymphocytes (CTL) eliminate malignant cells through recognition by the T-cell receptor (TCR) of specific antigenic peptides presented on the surface of cancer cells by major histocompatibility complex class I/beta-2-microglobulin complexes, and through killing of target cells, mainly by releasing the content of secretory lysosomes containing perforin and granzyme B. T-cell adhesion molecules and, in particular, lymphocyte-function-associated antigen-1 and CD103 integrins, and their cognate ligands, respectively, intercellular adhesion molecule 1 and E-cadherin, on target cells, are involved in strengthening the interaction between CTL and tumor cells. Tumor-specific CTL have been isolated from tumor-infiltrating lymphocytes and peripheral blood lymphocytes (PBL) of patients with varied cancers. TCRβ-chain gene usage indicated that CTL identified in vitro selectively expanded in vivo at the tumor site compared to autologous PBL. Moreover, functional studies indicated that these CTL mediate human leukocyte antigen class I-restricted cytotoxic activity toward autologous tumor cells. Several of them recognize truly tumor-specific antigens encoded by mutated genes, also known as neoantigens, which likely play a key role in antitumor CD8 T-cell immunity. Accordingly, it has been shown that the presence of T lymphocytes directed toward tumor neoantigens is associated with patient response to immunotherapies, including ICI, adoptive cell transfer, and dendritic cell-based vaccines. These tumor-specific mutation-derived antigens open up new perspectives for development of effective second-generation therapeutic cancer vaccines.

In silico Analysis of TCR Vβ7 of Two Patients with Type 1 Diabetes Mellitus

OBJECTIVE

To compare the sequences and crystal structures of variable region of beta chain 7 (Vβ7) of T cell receptor (TCR) of two patients with type 1 diabetes mellitus (T1DM).

PATIENTS AND METHODS

The skewness of TCR Vβ7 of two T1DM patients were detected with real-time florescence quantitative polymerase chain reaction (FQ-PCR) and deoxyribonucleic acid (DNA) melting curve analysis technique followed by being sequenced, the crystal structures of them were simulated according to CPH models 2.0 Server, IMGT database, and RasMol 2 software.

RESULTS

The whole sequences of TCR Vβ7 of T1DM patient-1 were "CASRTAGQYEQYFGPGTR", that of patient-2 were "CASRTAGQYEQFFGPGTR"; the only difference between them lied on the 12(th) amino acid. The crystal structures of Vβ7 of the two patients simulated with backbone model were rather similar, while that with sphere model were obviously different.

CONCLUSION

Although the TCR Vβ7 of the T1DM patients share the similar gene sequences, their crystal structures simulated with sphere model are different, and the mechanism needs further study.

Serial transfer of a transplantable tumor: implications for Marek's vaccine mechanisms

The mechanism of Marek's disease (MD) vaccination to prevent the lymphoproliferative disease in chickens is not well understood. It is generally recognized that vaccination prevents disease, including the induction of T-cell tumors, but it does not prevent the pathogenic virus from infecting and replicating in the vaccinated host, nor does it prevent bird to bird spread of the oncogenic virus. The stage at which the vaccinated immune system intervenes in the process from infection to the induction of tumors remains obscure. Using a transplantable tumor induced by the Md5 strain of MD virus (MDV), we show that CVI988 vaccination does not prevent the induction of transplantable tumors in the 15I(5) x 7(1) chicken line. A monoclonal tumor with a V beta 1 T-cell receptor spectratype of 207 base pairs was used to follow the transplantable tumor in serial passages in vivo. This transplantable tumor could be passed in vaccinated birds. The length of time between vaccination and challenge (5 to 12 days) had little or no influence on the ability to transfer the tumor. There was variability in the manifestation of the disease produced by the transplanted tumor. Some chickens presented as normal but were still capable of transmitting the transplanted tumor to newly vaccinated recipients via their blood. This indicates that some chickens can control, but not eliminate, the tumor. The variables inducing health or disease in the challenged chickens remain obscure, but environmental or other factors likely depress the immune system allowing the tumor to overwhelm the immune system.

Analysis of the interindividual conservation of T cell receptor alpha- and beta-chain variable regions gene in the peripheral blood of patients with systemic lupus erythematosus

The aim of this study was to find conserved motifs in specific T cell receptor (TCR) alpha- and beta-chains, and to analyse the association between complementarity determining region 3 (CDR3) spectratype and systemic lupus erythematosus (SLE) activity. TCR alpha-and beta-chain CDR3 spectratypes were analysed in 20 SLE patients. The CDR3 spectratypes of three patients were monitored over time, and the CDR3 regions of clonally expanded T cells were sequenced. CDR3 spectratype analysis showed prominent usage of TCR AV8, AV14, AV23, AV30, AV31, BV2, BV8, BV11, BV14, BV16, BV19 and BV24 families in SLE patients. The CDR3 spectratype showed dynamic change correlating with SLE activity. The sequence of the CDR3 region in clonally expanded T cells suggested a conserved GGX amino acid motif in both alpha- and beta-chains. The Ja34 and Jb2s1 region genes were found in high frequency. Both TCR Valpha and Vbeta gene usage is highly restricted in SLE, suggesting that the TCRs recognize a limited number of antigenic epitopes. The conserved motifs and limited use of joining region genes may indicate the recognition of similar antigenic epitopes in multiple individuals.