Sarah McCormack

Human papilloma virus-specific T cells can be generated from naïve T cells for use as an immunotherapeutic strategy for immunocompromised patients.

Human papilloma virus (HPV) is a known cause of cervical cancer, squamous cell carcinoma and laryngeal cancer. Although treatments exist for HPV-associated malignancies, patients unresponsive to these therapies have a poor prognosis. Recent findings from vaccine studies suggest that T-cell immunity is essential for disease control. Because Epstein-Barr Virus (EBV)-specific T cells have been highly successful in treating or preventing EBV-associated tumors, we hypothesized that the development of a manufacturing platform for HPV-specific T cells from healthy donors could be used in a third-party setting to treat patients with high-risk/relapsed HPV-associated cancers. Most protocols for generating virus-specific T cells require prior exposure of the donor to the targeted virus and, because the seroprevalence of high-risk HPV types varies greatly by age and ethnicity, manufacturing of donor-derived HPV-specific T cells has proven challenging. We, therefore, made systematic changes to our current Good Manufacturing Practice (GMP)-compliant protocols to improve antigen presentation, priming and expansion for the manufacture of high-efficacy HPV-specific T cells. Like others, we found that current methodologies fail to expand HPV-specific T cells from most healthy donors. By optimizing dendritic cell maturation and function with lipopolysaccharide (LPS) and interferon (IFN)γ, adding interleukin (IL)-21 during priming and depleting memory T cells, we achieved reliable expansion of T cells specific for oncoproteins E6 and E7 to clinically relevant amounts (mean, 578-fold expansion; n = 10), which were polyfunctional based on cytokine multiplex analysis. In the third-party setting, such HPV-specific T-cell products might serve as a potent salvage therapy for patients with HPV-associated diseases.

Antiviral T Cells for Adenovirus in the Pretransplant Period: A Bridge Therapy for Severe Combined Immunodeficiency.

Viral infections can be life threatening in patients with severe combined immunodeficiency (SCID) and other forms of profound primary immunodeficiency disorders both before and after hematopoietic stem cell transplantation (HSCT). Adoptive immunotherapy with virus-specific T cells (VSTs) has been utilized in many patients in the setting of HSCT, but has very rarely been attempted for treatment of viral infections before HSCT. Here we describe the use of VSTs in an infant with RAG1 SCID who had developed disseminated adenovirus which failed to improve on cidofovir. Adenovirus cleared following 2 doses of VSTs and marrow infusion from a matched unrelated donor, without incidence of graft versus host disease. T cell receptor-b sequencing demonstrated expansion of adenovirus-specific T cell fraction of the VSTs, suggesting that infusion facilitated viral clearance. This report suggests that VSTs are likely safe in the pre-HSCT period, and may be a useful bridge therapy for infants with SCID and persistent viral infections.

685. Restoration of Antiviral Immunity Following Hematopoietic Stem Cell Transplantation with Virus-Specific T-Lymphocyte Therapy

Background: Adoptive immunotherapy using virus-specific cytotoxic T-lymphocyte (VST) products has been successful in restoring antiviral immunity after hematopoietic stem cell transplantation (HSCT). VST may be produced from a stem cell donor in 10-14 days using current rapid protocols, or banked, partially-HLA matched VST may be used as an “off the shelf” treatment. Objective: To evaluate the clinical efficacy of HSCT donor-derived VST and third-party VST for prevention or treatment of CMV, EBV, and adenovirus following HSCT. Design/Methods: VST were cultured from HSCT or third-party donors using a GMP-compliant rapid-manufacture protocol. VST were tested for specificity and non-alloreactivity via IFN-γ ELISpot and cytotoxicity assays. Patients were monitored for 45 days following infusion for toxicity and for up to 22 months for immune reconstitution. Results: Nineteen patients received VST on existing protocols, of which 15 products were derived from HSCT donors, and 6 were from partially matched, third-party donors. Sixteen patients were treated for CMV (N=11), EBV (N=5), and/or adenovirus infections(n=3), of which fourteen (88%) had partial or complete antiviral responses. Immune reconstitution against targeted viruses was seen using IFN-g ELISpot at a median time of 28 days following infusion. Three patients developed grade I-II GVHD within 45 days of VST infusion, all of which was treatment responsive. Sixteen of the 19 patients remain alive and free of active viral infection up to 22 months post-VST infusion. Conclusions: VST are effective for the restoration of antiviral following HSCT. Expansion of targeted viruses may further extend the utility of this therapy.