Development of a scalable single process for producing SARS-CoV-2 RBD monomer and dimer vaccine antigens.

We have developed a single process for producing two key COVID-19 vaccine antigens: SARS-CoV-2 receptor binding domain (RBD) monomer and dimer. These antigens are featured in various COVID-19 vaccine formats, including SOBERANA 01 and the licensed SOBERANA 02, and SOBERANA Plus. Our approach involves expressing RBD (319-541)-His6 in Chinese hamster ovary (CHO)-K1 cells, generating and characterizing oligoclones, and selecting the best RBD-producing clones.

Molecular reshaping of phage-displayed Interleukin-2 at beta chain receptor interface to obtain potent super-agonists with improved developability profiles.

Interleukin-2 (IL-2) engineered versions, with biased immunological functions, have emerged from yeast display and rational design. Here we reshaped the human IL-2 interface with the IL-2 receptor beta chain through the screening of phage-displayed libraries. Multiple beta super-binders were obtained, having increased receptor binding ability and improved developability profiles.

Domain-level epitope mapping of polyclonal antibodies against HER-1 and HER-2 receptors using phage display technology.

HER-1 and HER-2 are tumor-associated antigens overexpressed in several epithelial tumors, and successfully targeted by therapeutic approaches against cancer. Vaccination with their recombinant extracellular domains has had encouraging results in the pre-clinical setting. As complex humoral responses targeting multiple epitopes within each antigen are the ultimate goal of such active immunotherapy strategies, molecular dissection of the mixture of antibody specificities is required.

SARS-CoV-2 RBD-Tetanus Toxoid Conjugate Vaccine Induces a Strong Neutralizing Immunity in Preclinical Studies.

Controlling the global COVID-19 pandemic depends, among other measures, on developing preventive vaccines at an unprecedented pace. Vaccines approved for use and those in development intend to elicit neutralizing antibodies to block viral sites binding to the host's cellular receptors. Virus infection is mediated by the spike glycoprotein trimer on the virion surface via its receptor binding domain (RBD).

High throughput functional epitope mapping: revisiting phage display platform to scan target antigen surface.

Antibody engineering must be accompanied by mapping strategies focused on identifying the epitope recognized by each antibody to define its unique functional identity. High throughput fine specificity determination remains technically challenging. We review recent experiences aimed at revisiting the oldest and most extended display technology to develop a robust epitope mapping platform, based on the ability to manipulate target-derived molecules (ranging from the whole native antigen to antigen domains and smaller fragments) on filamentous phages.

Delineating the functional map of the interaction between nimotuzumab and the epidermal growth factor receptor.

Molecular details of epidermal growth factor receptor (EGFR) targeting by nimotuzumab, a therapeutic anti-cancer antibody, have been largely unknown. The current study delineated a functional map of their interface, based on phage display and extensive mutagenesis of both the target antigen and the Fv antibody fragment. Five residues in EGFR domain III (R353, S356, F357, T358, and H359T) and the third hypervariable region of nimotuzumab heavy chain were shown to be major functional contributors to the interaction.

A combinatorial mutagenesis approach for functional epitope mapping on phage-displayed target antigen: application to antibodies against epidermal growth factor.

Although multiple different procedures to characterize the epitopes recognized by antibodies have been developed, site-directed mutagenesis remains the method of choice to define the energetic contribution of antigen residues to binding. These studies are useful to identify critical residues and to delineate functional maps of the epitopes. However, they tend to underestimate the roles of residues that are not critical for binding on their own, but contribute to the formation of the target epitope in an additive, or even cooperative, way.

Fine epitope specificity of antibodies against interleukin-2 explains their paradoxical immunomodulatory effects.

The functional dichotomy of antibodies against interleukin-2 (IL-2) is thought to depend upon recognition of different cytokine epitopes. Beyond functional studies, the only molecular evidence obtained so far located the epitopes recognized by the immunoenhancing antibodies S4B6 and JES6-5H4 within the predicted interface of IL-2 with the α receptor subunit, explaining the preferential stimulation of effector cells displaying only β and γ receptor chains. A consistent functional map of the epitope bound by the immunoregulatory antibody JES6-1A12 has now been delineated by screening the interactions of phage-displayed antigen variants (with single and multiple mutations) and antigen mimotopes.