Immunocompromised individuals are at high risk for life-threatening diseases, especially those caused by cytomegalovirus (CMV), Epstein-Barr virus (EBV) and adenovirus. Conventional therapeutics are primarily active only against CMV, and resistance is frequent. Adoptive transfer of polyclonal cytotoxic T lymphocytes (CTLs) specific for CMV or EBV seems promising, but it is unclear whether this strategy can be extended to adenovirus, which comprises many serotypes. In addition, the preparation of a specific CTL line for each virus in every eligible individual would be impractical. Here we describe genetic modification of antigen-presenting cell lines to facilitate the production of CD4(+) and CD8(+) T lymphocytes specific for CMV, EBV and several serotypes of adenovirus from a single cell culture. When administered to immunocompromised individuals, the single T lymphocyte line expands into multiple discrete virus-specific populations that supply clinically measurable antiviral activity. Monoculture-derived multispecific CTL infusion could provide a safe and efficient means to restore virus-specific immunity in the immunocompromised host.

• Banked third-party virusspecific T cells can safely and rapidly treat severe or intractable viral infections after HSCT.Virus-specific T cell (VST) lines could provide useful antiviral prophylaxis and treatment of immune-deficient patients if it were possible to avoid the necessity of generating a separate line for each patient, often on an emergency basis. We prepared a bank of 32 virus-specific lines from individuals with common HLA polymorphisms who were immune to Epstein-Barr virus (EBV), cytomegalovirus, or adenovirus. A total of 18 lines were administered to 50 patients with severe, refractory illness because of infection with one of these viruses after hematopoietic stem cell transplant. The cumulative rates of complete or partial responses at 6 weeks postinfusion were 74.0% (95% CI, 58.5%-89.5%) for the entire group (n 5 50), 73.9% (95% CI, 51.2% -96.6%) for cytomegalovirus (n 5 23), 77.8% for adenovirus (n 5 18), and 66.7% (95% CI, 36.9%-96.5%) for EBV (n 5 9). Only 4 responders had a recurrence or progression. There were no immediate infusionrelated adverse events, and de novo graft-versus-host disease developed in only 2 patients. Despite the disparity between the lines and their recipients, the mean frequency of VSTs increased significantly postinfusion, coincident with striking decreases in viral DNA and resolution of clinical symptoms. The use of banked third-party VSTs is a feasible and safe approach to rapidly treat severe or intractable viral infections after stem cell transplantation. This study is registered at www.clinicaltrials.gov as NCT00711035. (Blood. 2013;121(26):5113-5123)

Purpose Improvement of cure rates for patients treated with allogeneic hematopoietic stem-cell transplantation (HSCT) will require efforts to decrease treatment-related mortality from severe viral infections. Adoptively transferred virus-specific T cells (VSTs) generated from eligible, third-party donors could provide broad antiviral protection to recipients of HSCT as an immediately available off-the-shelf product. Patient and Methods We generated a bank of VSTs that recognized five common viral pathogens: Epstein-Barr virus (EBV), adenovirus (AdV), cytomegalovirus (CMV), BK virus (BKV), and human herpesvirus 6 (HHV-6). The VSTs were administered to 38 patients with 45 infections in a phase II clinical trial. Results A single infusion produced a cumulative complete or partial response rate of 92% (95% CI, 78.1% to 98.3%) overall and the following rates by virus: 100% for BKV (n = 16), 94% for CMV (n = 17), 71% for AdV (n = 7), 100% for EBV (n = 2), and 67% for HHV-6 (n = 3). Clinical benefit was achieved in 31 patients treated for one infection and in seven patients treated for multiple coincident infections. Thirteen of 14 patients treated for BKV-associated hemorrhagic cystitis experienced complete resolution of gross hematuria by week 6. Infusions were safe, and only two occurrences of de novo graft-versus host disease (grade 1) were observed. VST tracking by epitope profiling revealed persistence of functional VSTs of third-party origin for up to 12 weeks. Conclusion The use of banked VSTs is a feasible, safe, and effective approach to treat severe and drug-refractory infections after HSCT, including infections from two viruses (BKV and HHV-6) that had never been targeted previously with an off-the-shelf product. Furthermore, the multispecificity of the VSTs ensures extensive antiviral coverage, which facilitates the treatment of patients with multiple infections.

It remains difficult to treat the multiplicity of distinct viral infections that afflict immunocompromised patients. Adoptive transfer of virus-specific T-cells (VSTs) can be safe and effective, but such cells have been complex to prepare and limited in anti-viral range. We now demonstrate the feasibility and clinical utility of rapidly-generated single-culture VSTs that recognize 12 immunogenic antigens from 5 viruses (Epstein-Barr virus, adenovirus, cytomegalovirus, BK virus, and Human Herpesvirus 6) that frequently cause disease in immunocompromised patients. When administered to 11 recipients of allogeneic transplants, 8 of whom had up to 4 active infections with the targeted viruses, these VSTs proved safe in all subjects and produced an overall 94% virological and clinical response rate that was sustained long-term.

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Human CD4 ؉ T-helper 1 cell responses to Epstein-Barr virus (EBV) infection are likely to be important in the maintenance of virus-specific CD8؉ memory and/or as antiviral effectors in their own right. The present work has used overlapping peptides as stimulators of gamma interferon release (i) to identify CD4 ؉ epitopes within four EBV latent-cycle proteins, i.e., the nuclear antigens EBNA1 and EBNA3C and the latent membrane proteins LMP1 and LMP2, and (ii) to determine the frequency and magnitude of memory responses to these proteins in healthy virus carriers. Responses to EBNA1 and EBNA3C epitopes were detected in the majority of donors, and in the case of EBNA1, their antigen specificity was confirmed by in vitro reactivation and cloning of CD4 ؉ T cells using protein-loaded dendritic cell stimulators. By contrast, responses to LMP1 and LMP2 epitopes were seen much less frequently. EBV latent-cycle proteins therefore display a marked hierarchy of immunodominance for CD4 ؉ T-helper 1 cells (EBNA1, EBNA3C Ͼ Ͼ Ͼ Ͼ LMP1, LMP2) which is different from that identified for the same proteins with respect to CD8؉ -T-cell responses (EBNA3C > EBNA1 > LMP2 Ͼ Ͼ Ͼ Ͼ LMP1). Furthermore, the range of CD4؉ memory T-cell frequencies in peripheral blood of healthy virus carriers was noticeably lower and narrower than the corresponding range of latent antigen-specific CD8؉ -Tcell frequencies.

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Epstein-Barr virus (EBV)-associated tumors developing in immunocompetent individuals present a challenge to immuno-therapy, since they lack expression of immunodominant viral antigens. However, the tumors consistently express viral proteins including LMP2, which are immunologi-cally "weak" but may nonetheless be targets for immune T cells. We previously showed that a majority of cytotoxic T lym-phocytes (CTLs) reactivated using EBV-transformed B-lymphoblastoid cells lines (LCLs) contained minor populations of LMP2-specific T cells and homed to tumor sites. However, they did not produce remissions in patients with bulky disease. We have now used gene transfer into antigen-presenting cells (APCs) to augment the expression and immunogenicity of LMP2. These modified APCs increased the frequency of LMP2-specific CTLs by up to 100-fold compared with unmodified LCL-APCs. The LMP2-specific population expanded and persisted in vivo without adverse effects. Nine of 10 patients treated in remission of high-risk disease remain in remission, and 5 of 6 patients with active relapsed disease had a tumor response, which was complete in 4 and sustained for more than 9 months. It is therefore possible to generate immune responses to weak tumor antigens by ex vivo genetic modification of APCs and the CTLs so produced can have substantial antitumor activity. This study is registered at http://www. cancer.gov/clinicaltrials (protocol IDs: BCM-H-9936, NCT00062868, NCT00070226).