Rapid generation of multivirus-specific T lymphocytes for the prevention and treatment of respiratory viral infections

Abstract

Acute upper and lower respiratory tract infections (RTI) due to community-acquired respiratory viruses (CARV) including respiratory syncytial virus (RSV), influenza, parainfluenza virus (PIV) and human metapneumovirus (hMPV) are a major public health problem.1 For example, RSV-induced bronchiolitis is the most common reason for hospital admission in children under one year of age,2-4 while the Center for Disease Control (CDC) estimates that, annually, Influenza accounts for up to 35.6 million illnesses worldwide, between 140,000 and 710,000 hospitalizations, annual costs of approximately $87.1 billion in disease management in the US alone, and between 12,000 and 56,000 deaths. Thus, CARV are a leading cause of morbidity and mortality worldwide, with individuals whose immune systems are naive (e.g. young children) or compromised being the most vulnerable. For example, in allogeneic hematopoietic stem cell transplant (HSCT) recipients, the incidence of CARV-related respiratory viral diseases is as high as 40%.5 While most patients initially present with rhinorrhea, cough and fever, in approximately 50% of cases, infections progress to the lower respiratory tract and are characterized by severe symptoms including pneumonia and bronchiolitis and mortality rates of 23-50%.6-9 There are neither approved preventative vaccines nor antiviral drugs for hMPV10 and PIV11 and for Influenza the preventative vaccine is not indicated unless patients are at least six months post-HSCT.12 Aerosolized ribavirin (RBV) has been approved by the US Food and Drug Administration (FDA) for the treatment of RSV, but it is extremely costly (5-day course = $149,756) and logistically difficult to administer, requiring a specialized nebulization device that connects to an aerosol tent surrounding the patient.13-16 Thus, the lack of approved antiviral agents for many clinically problematic CARV, and the high cost and complexity of administering aerosolized RBV, underscores the need for alternative treatment strategies. Our group has previously demonstrated that the adoptive transfer of in vitro-expanded virus-specific T cells (VST) can safely and effectively prevent and treat infections associated with both latent [Epstein-Barr virus (EBV), cytomegalovirus (CMV), BK virus (BKV), human her-pesvirus 6 (HHV6)] and lytic [adenovirus (AdV)] viruses in allogeneic HSCT recipients.17,18 Given that susceptibility to CARV is associated with underlying cellular immune deficiency,1,5,6 in the current study, we explored the feasibility of extending the therapeutic range of VST therapy to include Influenza, RSV, hMPV and PIV-3. We here describe a mechanism by which we can rapidly generate a single preparation of polyclonal (CD4+ and CD8+) VST with specificity for 12 immunodominant antigens derived from our four target viruses using Good Manufacturing Practices (GMP)-compliant manufacturing methodologies. The viral proteins used for stimulation were chosen on the basis of both their immunogenicity to T cells and their sequence conservation.19-21 The expanded cells are Th1-polarized, polyfunctional and selectively able to react to and kill, viral antigen-expressing target cells with no activity against non-infected autologous or allogeneic targets, attesting to both their selectivity for viral targets and their safety for clinical use. We anticipate such multi-respiratory virus-targeted cells (multi-R-VST) will provide broad spectrum benefit to immunocompromised individuals with uncontrolled CARV infections.