Transcriptomic analysis reveals optimal cytokine combinations for SARS-CoV-2-specific T cell therapy products

Adoptive T cell immunotherapy has been used to restore immunity against multiple viral targets in immunocompromised patients after bone-marrow transplantation and has been proposed as a strategy for preventing coronavirus 2019 (COVID-19) in this population. Ideally, expanded severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-virus-specific T cells (CSTs) should demonstrate marked cell expansion, T cell specificity, and CD8+ T cell skewing prior to adoptive transfer. However, current methodologies using IL-4 + IL-7 result in suboptimal specificity, especially in CD8 cells. Using a microexpansion platform, we screened various cytokine cocktails (IL-4 + IL-7, IL-15, IL-15 + IL-4, IL-15 + IL-6, and IL-15 + IL-7) for the most favorable culture conditions. IL-15 + IL-7 optimally balanced T cell expansion, polyfunctionality, and CD8+ T cell skewing of a final therapeutic T cell product. Additionally, the transcriptomes of CD4 and CD8 T cells cultured with IL-15 + IL-7 displayed the strongest induction of antiviral type I interferon (IFN) response genes. Subsequently, microexpansion results were successfully translated to a Good Manufacturing Practice (GMP)-applicable format where IL-15 + IL-7 outperformed IL-4 + IL-7 in specificity and expansion, especially in the desirable CD8 T cell compartment. These results demonstrate the functional implications of IL-15-, IL-4-, and IL-7-containing cocktails for therapeutic T cell expansion, which could have broad implication for cellular therapy, and pioneer the use of RNA sequencing (RNA-seq) to guide viral-specific T cell (VST) product manufacturing

Outcomes following posttransplant viral-specific T-cell therapy in patients with sickle cell disease

Hematopoietic stem cell transplantation (HSCT) is increasingly used as a curative approach for sickle cell disease (SCD). With the risk of graft-versus-host disease (GVHD), especially in the HLA-mismatched donors, intense immunosuppression is required leading to an increased risk of viral infection. Post-HSCT, adoptive transfer of virus-specific T cell (VSTs) therapies have not been well-studied in SCD patients. Here, we report the outcomes of patients with SCD at a single-center who received VSTs post-transplant to prevent or treat virus infections. Thirteen patients who received HSCT from HLA-matched (n=9) or mismatched (n=4) donors for SCD were treated with a total of 15 VST products for the treatment or prophylaxis of multiple viruses (cytomegalovirus, ebstein barr virus, adenovirus, BK virus, human herpes virus 6 +/- human parainfluenza virus 3). Of the patients evaluated, 46.2% (n=6)) received VSTs as treatment of virus infection. Eighty percent of patients with active viremia (n=4/5) achieved remission of at least 1 target virus. Seven additional patients (53.8%) received VSTs prophylactically and 6/7 (85.7%) remained virus-free post-infusion. No immediate infusion-related toxicities occurred, and severe de novo acute GVHD occurred in only 2 (15.4%) patients. Given the good safety profile, high-rate of clinical responses and sustained remissions when administered with standard anti-viral treatments, the routine use of VSTs post-HSCT as prophylaxis or treatment may improve the overall safety of transplant for patients with SCD

SARS-CoV-2-Specific T Cell Responses Are Stronger in Children With Multisystem Inflammatory Syndrome Compared to Children With Uncomplicated SARS-CoV-2 Infection

Background: Despite similar rates of infection, adults and children have markedly different morbidity and mortality related to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Compared to adults, children have infrequent severe manifestations of acute infection but are uniquely at risk for the rare and often severe Multisystem Inflammatory Syndrome in Children (MIS-C) following infection. We hypothesized that these differences in presentation are related to differences in the magnitude and/or antigen specificity of SARS-CoV-2-specific T cell (CST) responses between adults and children. We therefore set out to measure the CST response in convalescent adults versus children with and without MIS-C following SARS-CoV-2 infection. Methods: CSTs were expanded from blood collected from convalescent children and adults post SARS-CoV-2 infection and evaluated by intracellular flow cytometry, surface markers, and cytokine production following stimulation with SARS-CoV-2-specific peptides. Presence of serum/plasma antibody to spike and nucleocapsid was measured using the luciferase immunoprecipitation systems (LIPS) assay. Findings: Twenty-six of 27 MIS-C patients, 7 of 8 non-MIS-C convalescent children, and 13 of 14 adults were seropositive for spike and nucleocapsid antibody. CST responses in MIS-C patients were significantly higher than children with uncomplicated SARS-CoV-2 infection, but weaker than CST responses in convalescent adults. Interpretation: Age-related differences in the magnitude of CST responses suggest differing post-infectious immunity to SARS-CoV-2 in children compared to adults post uncomplicated infection. Children with MIS-C have CST responses that are stronger than children with uncomplicated SARS-CoV-2 infection and weaker than convalescent adults, despite near uniform seropositivity