Resistance and susceptibility markers of SARS-CoV-2 infection in neutrophils response from discordant couples 4014

Abstract Description The immune system is essential to control and eliminate pathogens such as SARS-CoV-2, the agent of COVID-19. Studying the differential responses of individuals exposed to the same viral strain within discordant couples (one partner infected, the other not) can enhance our understanding of infection responses. This study focuses on the neutrophil response in such couples, aiming to identify and evaluate resistance and susceptibility markers through the expression of ACE2, TLR4, and TLR9 receptors, cytokine production, and NETs release following different stimuli. Our findings reveal significant differences in responses. When COVID-19-negative cells were stimulated with ODN CpG, the percentage of ACE2+ neutrophils were increased, being higher than positive individuals. COVID-19-positive individuals have higher expression of TLR4+ in neutrophils without stimulation and after stimulation with LPS, ODN CpG, and inactivated SARS-CoV-2 in different concentrations. For TLR9 expression, this behavior is maintained in COVID-19-positive groups, except for those stimulated with ODN CpG. Regarding NETs release, COVID-19-positive individuals showed higher levels of NETs produced by neutrophils, even without acute infection, mainly at serum levels. After stimulation, COVID-19 negative have the highest levels comparatively and were also able to produce more IL-8. These differences in neutrophil responses may indicate potential resistance and susceptibility factors to SARS-CoV-2 infection. Funding Sources Funding: Supported by The São Paulo Research Foundation, FAPESP (process number 2021/13354-1) Topic Categories Viral Immunology (VIR)