Gamma delta T cells and resolution of cytomegalovirus infection in an HIV/HCV coinfected patient after liver transplantation

Revisiting the Role of γδ T Cells in Anti-CMV Immune Response after Transplantation

Gamma delta (γδ) T cells form an unconventional subset of T lymphocytes that express a T cell receptor (TCR) consisting of γ and δ chains. Unlike conventional αβ T cells, γδ T cells share the immune signature of both the innate and the adaptive immunity. These features allow γδ T cells to act in front-line defense against infections and tumors, rendering them an attractive target for immunotherapy. The role of γδ T cells in the immune response to cytomegalovirus (CMV) has been the focus of intense research for several years, particularly in the context of transplantation, as CMV reactivation remains a major cause of transplant-related morbidity and mortality. Therefore, a better understanding of the mechanisms that underlie CMV immune responses could enable the design of novel γδ T cell-based therapeutic approaches. In this regard, the advent of next-generation sequencing (NGS) and single-cell TCR sequencing have allowed in-depth characterization of CMV-induced TCR repertoire changes. In this review, we try to shed light on recent findings addressing the adaptive role of γδ T cells in CMV immunosurveillance and revisit CMV-induced TCR reshaping in the era of NGS. Finally, we will demonstrate the favorable and unfavorable effects of CMV reactive γδ T cells post-transplantation.

A promising sword of tomorrow: Human γδ T cell strategies reconcile allo-HSCT complications

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is potentially a curative therapeutic option for hematological malignancies. In clinical practice, transplantation associated complications greatly affected the final therapeutical outcomes. Currently, primary disease relapse, graft-versus-host disease (GVHD) and infections remain the three leading causes of a high morbidity and mortality in allo-HSCT patients. Various strategies have been investigated in the past several decades including human γδ T cell-based therapeutical regimens. In different microenvironments, human γδ T cells assume features reminiscent of classical Th1, Th2, Th17, NKT and regulatory T cells, showing diverse biological functions. The cytotoxic γδ T cells could be utilized to target relapsed malignancies, and recently regulatory γδ T cells are defined as a novel implement for GVHD management. In addition, human γδ Τ cells facilitate control of post-transplantation infections and participate in tissue regeneration and wound healing processes. These features potentiate γδ T cells a versatile therapeutical agent to target transplantation associated complications. This review focuses on insights of applicable potentials of human γδ T cells reconciling complications associated with allo-HSCT. We believe an improved understanding of pertinent γδ T cell functions would be further exploited in the design of innovative immunotherapeutic approaches in allo-HSCT, to reduce mortality and morbidity, as well as improve quality of life for patients after transplantation.

T10B9 monoclonal antibody: a short-acting nonstimulating monoclonal antibody that spares gammadelta T-cells and treats and prevents cellular rejection

T10B9.1A-31/MEDI-500 is a nonmitogenic immunoglobulin M kappa murine monoclonal antibody (mAb) directed against the alpha-beta (αβ) heterodimer of the T-lymphocyte receptor complex. The hybridoma was first produced by fusing spleen cells from BALB/C mice immunized with human peripheral blood T-lymphocytes with SP2/O-Ag14 mutant myeloma cells. The mAb is produced and purified using multistep ion exchange and molecular sieve chromatography protocols. T10B9 has been used successfully to treat acute cellular rejection in renal transplantation and as an immunosuppression induction agent in heart and simultaneous kidney-pancreas transplantation. Because T10B9 is nonmitogenic and causes minimal cytokine release, both treatment of rejection and induction of immunosuppression were accomplished with significantly fewer and milder untoward effects (cytokine release syndrome) than its comparator OKT3. Since T10B9 is directed against the αβ heterodimer of the CD3 epitope, it spares the gamma delta (γδ) region. These gamma delta (γδ) T cells have a unique role in the immune response controlling many serious human diseases and perhaps facilitating the development of immunologic tolerance. T10B9 has a relatively short duration of action, depleting T cells for only 10 to 14 days, unlike the protracted depletion seen with thymoglobulin and Campath-1H. There is no B-lymphocyte depletion with T10B9 as there is with both of the aforementioned reagents. The lack of prolonged lymphocyte depletion may account for less infection observed with T10B9 treatment.