RESUMO
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.
RESUMO
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.