Moosmann, A. | bioRxiv Science

bioRxiv2021

Reconstitution of T cell immunity against EBV in the immunocompromised host by adoptive transfer of peptide-stimulated T cells after allogeneic stem cell transplantation

Reconstitution of T cell repertoire after allogeneic stem cell transplantation is a long and often incomplete process. As a result, reactivation of Epstein-Barr virus (EBV) is a frequent complication that may be treated by adoptive transfer of donor-derived EBV-specific T cells. We generated donor-derived EBV-specific T cells by peptide stimulation and adoptively transferred them to a patient with angioimmunoblastic T-cell lymphoma (AITL), who had developed persisting high titers of EBV concomitant to relapse after transplantation. T cell receptor beta (TCR{beta}) deep sequencing showed that the T cell repertoire of the patient early after transplantation (day 60) was strongly reduced and only very low numbers of EBV-specific T cells were detectable. Manufacturing and in vitro expansion of donor-derived EBV-specific T cells resulted in enrichment of EBV epitope-specific, HLA-restricted T cells. Monitoring after adoptive transfer revealed that the dominant TCR sequences from peptide-stimulated T cells persisted long-term and established an EBV-specific TCR clonotype repertoire in the host, with many of the EBV-specific TCRs present in the donor. This reconstituted repertoire was associated with immunological control of EBV and with lack of further AITL relapse. Author summaryA characteristic feature of all herpesviruses is their persistence in the hosts body after primary infection. Hence, the hosts immune system is confronted with the problem to control these viruses life-long. Well-known representative of the herpesvirus group are the classic Herpes-Simplex Virus (HSV-1) and Varicella Zoster Virus (VZV, causing chicken pox); a less known representative is Epstein Barr Virus (EBV, causing mononucleosis). When the immune system is severely compromised, for example after stem cell transplantation from a foreign (allogeneic) donor, these viruses can reappear, as they are already in the hosts body. Especially EBV cause life-threatening complications after stem cell transplantation and only reinforcement of the hosts immune system can reestablish viral control. Here we show that ex vivo manufactured EBV-specific T cells can reestablish long-term control of EBV and that these cells persist in the hosts body over months. These results give us a better understanding of viral immune reconstitution post-transplant and of clinically-relevant T cell populations against EBV.

immunology↗

bioRxiv2018

Antigen-specific T-cell receptor signatures of cytomegalovirus infection

Cytomegalovirus (CMV) is a prevalent human pathogen. The virus cannot be eliminated from the body, but is kept in check by CMV-specific T cells. Patients with an insufficient T-cell response, such as transplant recipients, are at high risk of developing CMV disease. However, the CMV-specific T-cell repertoire is complex, and is not yet clear which T cells protect best against virus reactivation and disease. Here we present a highly resolved characterization of CMV-specific CD8+ T cells based on enrichment by specific peptide stimulation and mRNA sequencing of their T-cell receptor {beta} chains (TCR{beta}). Our analysis included recently identified T-cell epitopes restricted through HLA-C, whose presentation is resistant to viral immunomodulation, and well-studied HLA-B-restricted epitopes. In 8 healthy virus carriers, we identified a total of 1052 CMV-specific TCR{beta} chains. HLA-C-restricted, CMV-specific TCR{beta} clonotypes the ex vivo T-cell response, and contributed the highest-frequency clonotype of the entire repertoire in 2 of 8 donors. We analyzed sharing and similarity of CMV-specific TCR{beta} sequences and identified 63 public or related sequences belonging to 17 public TCR{beta} families. In our cohort and in an independent cohort of 352 donors, the cumulative frequency of these public TCR{beta} family members was a highly discriminatory indicator of carrying both CMV infection and the relevant HLA type. Based on these findings, we propose CMV-specific TCR{beta} signatures as a biomarker for an antiviral T-cell response to identify patients in need of treatment and to guide future development of immunotherapy.

immunology↗