Successful In Vitro Priming of EBV-Specific CD8+ T Cells Endowed with Strong Cytotoxic Function from T Cells of EBV-Seronegative Children

Abstract

Epstein-Barr virus (EBV)-seronegative transplant recipients are at high risk of developing EBV-associated post-transplant lymphoproliferative disorder (PTLD), and would maximally benefit from an EBV-directed T-cell therapy for prevention or treatment of PTLD. So far, efforts to activate CD8+ EBV-specific cytotoxic T lymphocytes (CTL) endowed with high specific cytotoxicity from EBV-seronegative children have failed. We compared the CD8+ CTL priming efficiency of three different modified activation protocols, based on lymphoblastoid cell lines (LCL) stimulation potentially enhanced by either LCL presentation through dendritic cells, or selection of IFN-c + cultured cells, or culture in the presence of rhIL-12 and rhIL-7, according to the standard protocol for reactivation of EBVspecific CTL. We found that only specific LCL stimulation in the presence of rhIL-12 and rhIL-7 was able to reproducibly expand EBV-specific CD8+ CTL endowed with strong cytotoxic activity from truly EBVseronegative children. The lines thus activated, which included specificities toward EBV latent and lytic proteins, showed high percentage CD8+ T cells, with <10% naïve CD8+/CCR7+/CD45RA+ cells. Overall, the total number of CD8+ central memory cells, and of CCR7 T-cell effectors was comparable to that observed in healthy EBV-seropositive controls. In conclusion, it is feasible to activate EBV-specific CD8+ CTL with suitable characteristics for in vivo employment from EBVseronegative children.

Primary Human Immunodeficiency Virus Type 1-Specific CD8+T-Cell Responses Induced by Myeloid Dendritic Cells

“…Using a similar priming method with neonatal moDC and CMV antigen, others have found that there is a predominance of CD45R Ϫ CD27 ϩ T cells in the CMV-positive cell population (45). Similar to our results, Comoli et al (9) found a predominant population of CD45RA Ϫ CD27 Ϫ , and a secondary population of CD45RA ϩ CD27 Ϫ , CD8 ϩ T cells specific for EBV peptide in primed cultures from children. Likewise, Salio and colleagues (52) have reported that cord blood CD8 ϩ T cells primed to melanoma peptide are predominately CD45 Ϫ CCR7 Ϫ CD27 ϩ .…”

“…Likewise, Salio and colleagues (52) have reported that cord blood CD8 ϩ T cells primed to melanoma peptide are predominately CD45 Ϫ CCR7 Ϫ CD27 ϩ . However, different modes of in vitro priming of T cells can result in various degrees of memory T-cell differentiation (9). Clearly, one should be cautious about interpreting T-cell phe-…”

T Cell Immunotherapy for Immune Reconstitution and GVHD Prevention After Allogeneic Hematopoietic Stem Cell Transplantation

“…Moreover, the requirement that donors be seropositive donors to produce/expand specific T cells has been at least partly solved by the use of in vitro stimulation approaches for antigen-specific stimulation of naive (even CB-derived) T lymphocytes [65,66].…”

Pathogen specific T-lymphocytes for the reconstitution of the immunocompromised host

“…Additional cytokines released by activated T-helper cells facilitate PMN differentiation from HSC precursors (7). and cytokine cocktails including IL7, IL12 and IL15 for T-cell expansion [57][58][59]60 ]. Since this approach is demanding and time consuming, the use of T-cell lines stored in a biobank is a viable alternative.…”