Biosynthetic proteins targeting the SARS-CoV-2 spike as anti-virals

Screening and affinity optimization of single domain antibody targeting the SARS-CoV-2 nucleocapsid protein

The coronavirus disease 2019 (COVID-19) pandemic, which caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), lead to a crisis with devastating disasters to global public economy and health. Several studies suggest that the SARS-CoV-2 nucleocapsid protein (N protein) is one of uppermost structural constituents of SARS-CoV-2 and is relatively conserved which could become a specific diagnostic marker. In this study, eight single domain antibodies recognized the N protein specifically which were named pN01-pN08 were screened using human phage display library. According to multiple sequence alignment and molecular docking analyses, the interaction mechanism between antibody and N protein was predicted. ELISA results indicated pN01-pN08 with high affinity to protein N. To improve their efficacy, two fusion proteins were prepared and their affinity was tested. These finding showed that fusion proteins had higher affinity than single domain antibodies and will be used as diagnosis for the pandemic of SARS-CoV-2.

Early corticosteroid treatment enhances recovery from SARS-CoV-2 induced loss of smell in hamster

Among the numerous long COVID symptoms, olfactory dysfunction persists in ∼10 % of patients suffering from SARS-CoV-2 induced anosmia. Among the few potential therapies, corticoid treatment has been used for its anti-inflammatory effect with mixed success in patients. In this study, we explored its impact using hamster as an animal model. SARS-CoV-2 infected hamsters lose their smell abilities and this loss is correlated with damage of the olfactory epithelium and persistent presence of innate immunity cells. We started a dexamethasone treatment 2 days post infection, when olfaction was already impacted, until 11 days post infection when it started to recover. We observed an improvement of olfactory capacities in the animals treated with corticoid compared to those treated with vehicle. This recovery was not related to differences in the remaining damage to the olfactory epithelium, which was similar in both groups. This improvement was however correlated with a reduced inflammation in the olfactory epithelium with a local increase of the mature olfactory neuron population. Surprisingly, at 11 days post infection, we observed an increased and disorganized presence of immature olfactory neurons, especially in persistent inflammatory zones of the epithelium. This unusual population of immature olfactory neurons coincided with a strong increase of olfactory epithelium proliferation in both groups. Our results indicate that persistent inflammation of the olfactory epithelium following SARS-CoV-2 infection may alter the extent and speed of regeneration of the olfactory neuron population, and that corticoid treatment is effective to limit inflammation and improve olfaction recovery following SARS-CoV-2 infection.

Customizably designed multibodies neutralize SARS-CoV-2 in a variant-insensitive manner

The COVID-19 pandemic evolves constantly, requiring adaptable solutions to combat emerging SARS-CoV-2 variants. To address this, we created a pentameric scaffold based on a mammalian protein, which can be customized with up to 10 protein binding modules. This molecular scaffold spans roughly 20 nm and can simultaneously neutralize SARS-CoV-2 Spike proteins from one or multiple viral particles. Using only two different modules targeting the Spike's RBD domain, this construct outcompetes human antibodies from vaccinated individuals' serum and blocks in vitro cell attachment and pseudotyped virus entry. Additionally, the multibodies inhibit viral replication at low picomolar concentrations, regardless of the variant. This customizable multibody can be easily produced in procaryote systems, providing a new avenue for therapeutic development and detection devices, and contributing to preparedness against rapidly evolving pathogens.