Variances in Antiviral Memory T-Cell Repertoire of CD45RA- and CD62L-Depleted Lymphocyte Products Reflect the Need of Individual T-Cell Selection Strategies to Reduce the Risk of GvHD while Preserving Antiviral Immunity in Adoptive T-Cell Therapy

• Published in: Transfusion medicine and hemotherapy 2022-02, Vol.49 (1), p.30-43
• Main Authors: Mangare, Caroline, Tischer-Zimmermann, Sabine, Bonifacius, Agnes, Riese, Sebastian B., Dragon, Anna Christina, Blasczyk, Rainer, Maecker-Kolhoff, Britta, Eiz-Vesper, Britta
• Format: Article
• Language: English
• Subjects: Adenoviruses; Comparative analysis; Epstein-Barr virus; Health aspects; Hematopoietic stem cells; Immunotherapy; Infection; Interferon; Mortality; Research Article; T cells; Transplantation
• ISSN: 1660-3796; 1660-3818
• DOI: 10.1159/000516284

Introduction: Viral infections and reactivations still remain a cause of morbidity and mortality after hematopoietic stem cell transplantation due to immunodeficiency and immunosuppression. Transfer of unmanipulated donor-derived lymphocytes (DLI) represents a promising strategy for improving cellular immunity but carries the risk of graft versus host disease (GvHD). Depleting alloreactive naïve T cells (T N ) from DLIs was implemented to reduce the risk of GvHD induction while preserving antiviral memory T-cell activity. Here, we compared two T N depletion strategies via CD45RA and CD62L expression and investigated the presence of antiviral memory T cells against human adenovirus (AdV) and Epstein-Barr virus (EBV) in the depleted fractions in relation to their functional and immunophenotypic characteristics. Methods: T-cell responses against ppEBV_EBNA1, ppEBV_Consensus and ppAdV_Hexon within T N -depleted (CD45RA − /CD62L − ) and T N -enriched (CD45RA + /CD62L + ) fractions were quantified by interferon-gamma (IFN-γ) ELISpot assay after short- and long-term in vitro stimulation. T-cell frequencies and immunophenotypic composition were assessed in all fractions by flow cytometry. Moreover, alloimmune T-cell responses were evaluated by mixed lymphocyte reaction. Results: According to differences in the phenotype composition, antigen-specific T-cell responses in CD45RA − fraction were up to 2 times higher than those in the CD62L − fraction, with the highest increase (up to 4-fold) observed after 7 days for ppEBV_EBNA1-specific T cells. The CD4 + effector memory T cells (T EM ) were mainly responsible for EBV_EBNA1- and AdV_Hexon-specific T-cell responses, whereas the main functionally active T cells against ppEBV_Consensus were CD8 + central memory T cells (T CM ) and T EM . Moreover, comparison of both depletion strategies indicated that alloreactivity in CD45RA − was lower than that in CD62L − fraction. Conclusion: Taken together, our results indicate that CD45RA depletion is a more suitable strategy for generating T N -depleted products consisting of memory T cells against ppEBV_EBNA1 and ppAdV_Hexon than CD62L in terms of depletion effectiveness, T-cell functionality and alloreactivity. To maximally exploit the beneficial effects mediated by antiviral memory T cells in T N -depleted products, depletion methods should be selected individually according to phenotype composition and CD4/CD8 antigen restriction. T N -depleted DLIs may improve the clinical o