Inducing an immunosuppressed phenotype inprimary monocytes through exposure to viralproteins.

Sammanfattning: Background. Sepsis has been defined as a hyperactive dysregulated inflammatory response that can lead tohigh fevers, shock and multiple organ failure. However, newer findings indicate that LPS canreprogram monocytes to adopt a suppressed immune response-phenotype leading to increasedsusceptibility and mortality in a secondary infection. Furthermore, it is also stated that othertypes of immunostimulatory agents may also lead to reprogramming of the immune system,one of the latest candidates is the highly topical viral protein SARS-CoV-2 (COVID-19)which has been shown to be able to induce Endotoxin Tolerance Hallmarks. Aim. To investigate whether stimulation with viral NS1 protein can induce signs ofimmunosuppression in primary monocytes and reduce their proinflammatory response tosubsequent LPS exposure and other stimulants. Methods. For this project, CD14+ monocytes were isolated from remains of donated blood throughMagnetic Activated Cell Sorting. The isolated cells were seeded in culture media andstimulated with LPS, NS1 protein or were left untreated for 20 hours to create phenotypes.The cells were then exposed for a 2nd stimulation of LPS and NS1 protein and subsequentvalidation of TNF concentrations was later measured by ELISA. Results. Key findings in this study showed that LPS stimulation induced a statistically significantdifference in TNF production compared to untreated cells. However, this was not observed inNS1 protein stimulated cells. After restimulation with NS1 protein, the TNF production incells pre-exposed to NS1 showed no significant differences compared to cells previouslyunexposed. The TNF production after LPS stimulation was significantly different betweenthe normal cells and the endotoxin-tolerant cells. However, no differences were observed inthe LPS response in cells pre-exposed to the NS1 protein. Conclusion .The Viral protein NS1 cannot induce an immunosuppressed phenotype in primary monocytes