A Single Bout Of Exercise Enhances The Ex Vivo Manufacture Of Viral-specific T-cells

Abstract

Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) infections remain a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). The adoptive transfer of donor-derived viral-specific cytotoxic T-cells (CTLs) is an effective treatment for controlling CMV and EBV infections during HSCT. However, in many instances, the time taken to manufacture adequate numbers of CTLs from healthy donors is too long and requires the collection of large and impractical blood volumes. PURPOSE: To determine if a single exercise bout can augment the ex vivo manufacture of viral-specific T-cells from healthy donors. METHODS: Nine healthy CMV and EBV seropositive participants (mean ± SD age: 31.3 ± 3.3 years) completed a 30-min continuous cycling protocol at a workload corresponding to +15% of the individual blood lactate threshold. PBMCs (10x106) isolated before and immediately after exercise were stimulated with CMV (pp65 and IE1) and EBV (lmp2 and BMLF1) peptides and expanded over 8 days. At Day 8, viral-specific T-cells were enumerated using IFN-γ ELIPOST assays and the phenotypes of the expanded CTLs and viral-specific T-cells were determined by flow cytometry. RESULTS: Compared to CTLs expanded before exercise, the number of T-cells specific to CMV pp65, EBV lmp2, and EBV BMLF1 was markedly greater among the post-exercise expanded CTLs (fold-difference: CMVpp65: 2.6, EBV lmp-2: 2.5 and EBV BMLF-1: 4.4). Expanded CTLs predominantly consisted of effector memory (CD45RA-/CD62L-) and CD45RA+ effector memory (CD45RA+/CD62L-) T-cells, but no phenotypic differences were observed between CTLs expanded before and after exercise. Moreover, CTLs expanded before and after exercise were equally capable of killing viral-peptide pulsed autologous target cells in an MHC restricted manner. Viral-specific CTLs could not be expanded from a CMV/EBV seronegative participant, indicating that the augmenting effects of exercise are due to the priming and expansion of pre-existing memory T-cells. CONCLUSION: This is the first study to show that a single bout of exercise enhances the ex vivo manufacture of CMV and EBV-specific T-cells from healthy donors without altering their phenotype or function. Exercise may therefore serve as a safe adjuvant to improve viral-specific T-cell generation for HSCT.