Immune characterization of a Colombian familiar cluster of SARS-CoV-2 infection

Abstract

Introduction: Immunological markers have been described during COVID-19 and persist after recovery. Those immune alterations are associated with clinical features among SARS-CoV-2 infected individuals. Although, studies reporting a comprehensive analysis of these immune alterations are still limited. Objective: To evaluate the production of pro-inflammatory cytokines, antibody response, and phenotype and function of NK cells and T cells in a Colombian familiar cluster of SARS-CoV-2 infection. Materials and methods: Proinflammatory cytokines were evaluated by RT-PCR and ELISA. Frequency, phenotype and function of NK cells (cocultures with K562 cells) and T-cells (stimulated with Spike/RdRp peptides) were assessed by flow cytometry; anti-SARS-CoV-2 antibodies were determined by indirect immunofluorescence and plaque reduction neutralization assay. Results: During COVID-19, we observed a high pro-inflammatory cytokine production and reduced CD56bright NK cells and cytotoxic response. Compared with healthy controls, infected individuals had a higher frequency of dysfunctional CD8+ T cells CD38+HLA-DR-. During the acute phase, CD8+ T cells stimulated with viral peptides exhibited a monofunctional response characterized by a high IL-10 production. Nevertheless, during recovery, a bifunctional response was observed, characterized by the co-expression of CD107a and Granzyme B or Perforin. Conclusion: Although pro-inflammatory response is a hallmark of SARS-CoV-2 infection, other phenotypic and functional alterations in NK cells and CD8+ T cells could be associated with the outcome of COVID-19. However, additional studies are required to understand these alterations and, to guide future immunotherapy strategies.