Plasma therapy for treatment of COVID-19 patients:
We have identified several factors, including the time elapsed after infection, age, severity of COVID-19, and vaccination, that are positively associated with higher neutralizing antibody titers at the time of donation (Percivalle et al. Euro Surveill 2020; Sherina et al Med 2021). The hyperimmune plasma was also tested against emerging SARS-CoV-2 variants (Zuo et al. Lancet Reg Health West Pac 2023; Zuo et al. Nat Commun 2022). These findings will aid in optimizing the selection of hyperimmune convalescent plasma donors for plasma therapy. Furthermore, we conducted an assessment of the early utilization of hyperimmune plasma for treating COVID-19 patients requiring either non-invasive or invasive mechanical ventilation. Our observations revealed a reduction in hospital mortality among patients treated with hyperimmune plasma.
Isolation of monoclonal antibodies to SARS-CoV-2 using purification of B cells and phage display:
The consortium has identified the first lead monoclonal antibody candidates with exceptional neutralizing activity in less than 6 months. One of these antibodies, STE73-2E9, which was discovered from a naïve library, demonstrated the ability to neutralize SARS-CoV-2 with high efficiency in a plaque assay (Bertoglio et al., Nat Commun 2021). In addition, neutralizing human monoclonal antibodies C121, C144, and C135, which bind to distinct epitopes on the SARS-CoV-2 spike receptor binding domain (RBD), were obtained from convalescent patients (Robbiani et al., Nature 2020). More recently, antibodies targeting the conserved spike region were found and shown to be broadly neutralizing (Bianchini et al., Sci Immunol 2023).
Characterization and engineering of therapeutic antibodies:
The binding properties of monoclonal antibodies to SARS-CoV-2 were comprehensively characterized, encompassing aspects such as binding affinity, epitope mapping, and neutralization. Building upon the promising antibody candidates C121 and C135 (Robbiani et al., Nature 2020), a bispecific antibody known as CoV-X2 was engineered (De Gasparo et al., Nature 2021). This unique antibody simultaneously engages with two distinct sites on the RBD and effectively neutralizes the G614 virus variant in both cell culture assays and animal models.
In more recent developments, a different bispecific antibody named CoV-X4042, which combines sd1.040 and rbd.042 antibodies targeting the conserved spike region, has demonstrated the ability to neutralize all variants of concern, from the original virus to the currently circulating Omicron variants. Furthermore, this antibody has exhibited protective properties in animal models. Importantly, CoV-X4042 was manufactured in accordance with GMP standards, and toxicology tests were conducted (Bianchini et al., Sci Immunol 2023). In addition, we observed that dimeric and secretory IgA recombinant antibodies are more potent than the parental IgG for binding and neutralizing SARS-CoV-2 including Omicron variants. In hACE2 transgenic mice, a single intranasal dose of the dimeric IgA DXP-604 conferred prophylactic and therapeutic protection against Omicron.
Dissemination and exploitation of results:
ATAC rapidly disseminated results to help respond to the current COVID-19 epidemic. More than 56 papers were published, including publications with a high impact factor project, thereby reaching a wide scientific and medical audience. The project and results received important coverage on tv, radio, press, social media and were amply discussed by the general public in online blogs. The publications and related news were posted on the ATAC public-access website (
https://covidantibodytherapy.info/(opens in new window)) and the LinkedIn profile (
https://www.linkedin.com/in/atac-project-0aa1951aa/(opens in new window)).
