Epstein‐Barr virus (EBV) latent membrane protein‐1‐specific cytotoxic T lymphocytes targeting EBV‐carrying natural killer cell malignancies

Abstract

Epstein‐Barr virus (EBV)‐encoded latent membrane protein (LMP) 1 is a potential target for immunotherapy of some proportion of Hodgkin's disease cases, nasopharyngeal carcinomas, EBV‐associated natural killer (NK)/T lymphomas, and chronic active EBV infection (CAEBV). Since it is unknown whether EBV‐infected NK/T cells are susceptible to lysis by LMP1‐specific cytotoxic T lymphohcytes (CTL), we here tested the ability of mRNA‐transduced antigen‐presenting cells (APC) to stimulate rare LMP1‐specific CTL. A 43‐amino acid N‐terminal deletion mutant LMP1 (ΔLMP1) could be efficiently expressed in dendritic cells and CD40‐activated B cells upon mRNA electroporation. ΔLMP1‐expressing APC were found to stimulate LMP1‐specific CTL from a healthy donor and a CTL clone recognized a peptide, IIIILIIFI, presented by HLA‐A*0206 molecules. Processing and presentation of the antigenic peptide proved dependent on expression of an immunoproteasome subunit, low‐molecular‐weight protein‐7, as confirmed by RNA interference gene silencing. Furthermore, an EBV‐infected NK cell line derived from a patient with CAEBV, and another from an NK lymphoma with enforced HLA‐A*0206 expression, were specifically lysed by the CTL. Overall, these data suggest that immunotherapy targeting LMP1 in EBV‐associated NK lymphomas and CAEBV might serve as an alternative treatment modality.

Processing of Two Latent Membrane Protein 1 MHC Class I Epitopes Requires Tripeptidyl Peptidase II Involvement

“…CD8 ϩ T cells specific for another HLA-A2 epitope described in the same publication (10) were only tested against peptide-pulsed target cells. A recent publication by Demachi-Okamura et al (15) could only show lysis of LCLs in a 16-h cytotoxicity assay by a single LMP1-specific CD8…”

“…The latency type II program is limited to the expression of the nonimmunodominant Ags EBV nuclear Ag 1, latent membrane protein (LMP) 1, and LMP2, and is found in EBV-positive Hodgkin's disease (HD), nasopharyngeal carcinoma, and peripheral T/NK lymphomas (14). LMP1 is considered the main EBV-derived oncoprotein, and has been proposed by several groups as the ideal target for CTL-based immunotherapy against EBV-positive malignancies (10,11,(15)(16)(17). Several LMP1-specific MHC class I-restricted CTL epitopes have been reported, and studies with infused T cell lines containing both LMP1-and LMP2-specific CTLs have shown antiviral activity and immune effects, but only LMP2-specific T cells could be expanded in those patients (18).…”

Expression of Epstein-Barr Virus–Encoded Proteins in Extranodal NK/T-cell Lymphoma, Nasal Type (ENKL): Differences in Biologic and Clinical Behaviors of LMP1-Positive and -Negative ENKL

“…Although LMP1 may render the cell malignant phenotype, these alterations should be involved in host immune response and may affect the manner of tumor progression. Previous in vitro studies show that cytotoxic T cells against LMP1 can directly kill ENKLderived cell lines (35,36). Therefore, LMP1 may have reciprocal effects on the expressing cells, that is, even though LMP1-expressing cells show a malignant phenotype, an extrinsic immune system can eradicate these cells in vivo.…”

Adoptive cellular therapy with T cells specific for EBV-derived tumor antigens

“…LMP1-specific CTL can be activated and expanded from EBVseropositive donors with APCs including DCs or LCLs expressing a non-toxic form of LMP1 and LMP1-specific CTL generated by this method can recognize and kill LMP1 expressing lymphoma cells. [41][42] In addition in vivo activation of LMP1-specific CTL in an animal model resulted in regression of LMP1 positive tumors. 43…”