Expansion of EBV latent membrane protein 2a specific cytotoxic T cells for the adoptive immunotherapy of EBV latency type 2 malignancies: Influence of recombinant IL12 and IL15

Background: EBV-associated malignancies with a Type II latency gene expression pattern, such as EBV-positive HD, or nasopharyngeal carcinoma, frequently express the EBV latency Ag LMP2a. Hence, they provide a potential target for adoptive immunotherapy using in vitro-generated LMP2a-specific cytotoxic T lymphocytes (CTL). In this study, LMP2a-specific CTL mere specifically amplified and the influence of rIL12 and rIL15 on the culture outcome was tested. Methods: PBMC from donors were stimulated twice with autologous DC transduced with an adenovirus vector expressing LMP2a. This led to a significant expansion of LMP2a-tetramer-specific CTL, which were subsequently further expanded with autologous EBV-transformed B-lymphoblastoid cells (LCL). The addition of rIL12 and rIL15 to the standard IL2-containing culture medium enhanced the proliferation of LMP2a-specific CTL. Results: While rIL15 did not change the pattern of cytokines secreted by LMP2a-CTL, rIL12 enhanced the production of Th1/Tc1 cytokines, such as IFN-γ, while suppressing the production of the Th2/Tc2 cytokine IL5. Discussion: Stimulation of CTL cultures with rIL12 or rIL15 will generate CTL more rapidly, facilitating the application of this approach for patients with these EBV-associated disorders.