Ponente
Descripción
SARS-COV-2 causes the COVID-19 disease which has caused the infection and death of millions of people worldwide. In Cuba it has also had a high impact, since more than 1 million people have been infected with the disease. Due to this, vaccines have been developed based on different technological platforms. A conjugated candidate, called Soberana 02, was obtained in the Finlay Vaccine Institute. This Cuban vaccine uses the RBD viral protein chemically conjugated to tetanus toxoid as an antigen. The objective of this work is to obtain immunogenic RBD-TT conjugates with different antigen-carrier protein molar ratios, by a thiol-maleimide Michael addition reaction. For this, cysteine 538 of the monomeric RBD is selectively reduced and covalently bound to the TT protein, functionalized with maleimide groups. The conjugates were characterized by chemical-physical techniques such as: High Resolution Liquid Chromatography, Dynamic and Static Light Scattering, Circular Dichroism, Fluorescence, SDS-PAGE, colorimetric and immunochemical techniques, and they were immunologically evaluated. The thiol-maleimido Michael addition reaction allowed obtaining efficiently RBD-TT conjugates with different antigen-carrier protein molar ratios. The conjugated RBD preserves its molecular integrity, and no protein denaturation occurs during the conjugation process. All prepared RBD-TT conjugates have the appropriate quality attributes for use as the active ingredient of the Soberana 02 vaccine. The immunological evaluation allowed us to select the optimal range of antigen-carrier protein molar ratios to obtain immunogenic RBD-TT conjugates.
