Cells (Aug 2021)

Two-Step In Vitro Model to Evaluate the Cellular Immune Response to SARS-CoV-2

  • Juliana G. Melgaço,
  • Tamiris Azamor,
  • Andréa M. V. Silva,
  • José Henrique R. Linhares,
  • Tiago P. dos Santos,
  • Ygara S. Mendes,
  • Sheila M. B. de Lima,
  • Camilla Bayma Fernandes,
  • Jane da Silva,
  • Alessandro F. de Souza,
  • Luciana N. Tubarão,
  • Danielle Brito e Cunha,
  • Tamires B. S. Pereira,
  • Catarina E. L. Menezes,
  • Milene D. Miranda,
  • Aline R. Matos,
  • Braulia C. Caetano,
  • Jéssica S. C. C. Martins,
  • Thyago L. Calvo,
  • Natalia F. Rodrigues,
  • Carolina Q. Sacramento,
  • Marilda M. Siqueira,
  • Milton O. Moraes,
  • Sotiris Missailidis,
  • Patrícia C. C. Neves,
  • Ana Paula D. Ano Bom

Journal volume & issue
Vol. 10, no. 9
p. 2206


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The cellular immune response plays an important role in COVID-19, caused by SARS-CoV-2. This feature makes use of in vitro models’ useful tools to evaluate vaccines and biopharmaceutical effects. Here, we developed a two-step model to evaluate the cellular immune response after SARS-CoV-2 infection-induced or spike protein stimulation in peripheral blood mononuclear cells (PBMC) from both unexposed and COVID-19 (primo-infected) individuals (Step1). Moreover, the supernatants of these cultures were used to evaluate its effects on lung cell lines (A549) (Step2). When PBMC from the unexposed were infected by SARS-CoV-2, cytotoxic natural killer and nonclassical monocytes expressing inflammatory cytokines genes were raised. The supernatant of these cells can induce apoptosis of A549 cells (mock vs. Step2 [mean]: 6.4% × 17.7%). Meanwhile, PBMCs from primo-infected presented their memory CD4+ T cells activated with a high production of IFNG and antiviral genes. Supernatant from past COVID-19 subjects contributed to reduce apoptosis (mock vs. Step2 [ratio]: 7.2 × 1.4) and to elevate the antiviral activity (iNOS) of A549 cells (mock vs. Step2 [mean]: 31.5% × 55.7%). Our findings showed features of immune primary cells and lung cell lines response after SARS-CoV-2 or spike protein stimulation that can be used as an in vitro model to study the immunity effects after SARS-CoV-2 antigen exposure.