Immune Maturation Effects on Viral Neutralization and Avidity of Hyperimmunized Equine Anti-SARS-CoV-2 Sera

VIACAVA, MYRIAM BELÉN GONZÁLEZ; VARESE, AUGUSTO; MAZZITELLI, IGNACIO; LANARI, LAURA; ÁVILA, LUCÍA; VAMPA, MARÍA JULIA GARCÍA; GEFFNER, JORGE; CASCONE, OSVALDO; DOKMETJIAN, JOSÉ CHRISTIAN; DE ROODT, ADOLFO RAFAEL; FINGERMANN, MATÍAS

Antibodies

MDPI

Año: 2022 vol. 11

2073-4468

Mass-vaccination against COVID-19 is still a distant goal for most low-to-middle income countries. The experience gained through decades producing polyclonal immunotherapeutics (such as antivenoms) in many of those countries is being redirected to develop similar products able to neutralize SARS-CoV-2 infection. In this study we analyzed the biological activity (viral neutralization or NtAb) and immunochemical properties of hyperimmune horses’ sera (HHS) obtained during initial immunization (I) and posterior re-immunization (R) cycles using the RBD domain of the SARS-CoV-2 spike protein as antigen. HHS at the end of the R cycle showed higher NtAb titers when compared to those after the I cycle (35,585 vs. 7000 mean NtAb, respectively). Moreover, this increase paralleled an increase in avidity (95.2% to 65.2% mean avidity units, respectively). The results presented herein are relevant for manufacturers of these therapeutic tools against COVID-19.