Analysis of SARS-CoV-2 pathogenicity in COVID-19 cynomolgus macaque model reflecting human COVID-19 pathological conditions

Abstract

Abstract The pandemic of SARS-CoV-2 is still raging worldwide. Although rapid vaccination has been progressing in the world as a countermeasure against COVID-19, there are many issues regarding this disease including the emergence of variants and of their virulence that need to be elucidated, and a useful animal model is still necessary. We have established COVID-19 cynomolgus macaque (CM) model using healthy young CMs and CMs of advanced age (23 – 30 years of age, equivalent to 69 – 90 years of age in humans) with underlying diseases including diabetes and hyperlipidemia. There were differences between the pathological conditions in young macaques and elderly macaques of advanced age similar to observed in humans. In this study, we analyzed the virulence and pathology of SARS-CoV-2 variants of concern (VOCs) using COVID-19 CM model. Elucidation of how adaptive immunity in patients is induced by SARS-CoV-2 natural infection is critical for establishing a vaccine strategy, serologic therapies, public health control and prediction of infection. Therefore, we conducted the prolonged rechallenge analysis using COVID-19 CM model reinoculated with either the same or a different strain of SARS-CoV-2 that was used for the initial infection. Protective immunity against rechallenge of SARS-CoV-2 is under consideration, but in one elderly monkey reinfection showed transient pneumonia with increased levels of various serum cytokines and chemokines without detecting viruses in swab samples. Overall, the SARS-CoV-2-infected CM models reflected the pathology in humans, and studies using COVID-19 CM models should contribute to the elucidation of the complicated pathophysiology of COVID-19. Supported by grants from AMED (JP20fk0108414) and JSPS (21K19395)