Solid-phase protocol for tetraDVP linkers enables site-selective antibody bioconjugation with peptides and drugs.

Antibody conjugates, such as ADCs and PDCs, offer targeted delivery of various payloads, including cytotoxic small molecules, enzymes, and peptides, enhancing therapeutic selectivity and reducing off-target effects. A critical challenge in bioconjugation is achieving site-selectivity to preserve the native function of the antibody and ensure a controlled payload-to-antibody ratio (PAR). Current methods often necessitate genetic engineering, glycan engineering, or extensive chromatographic purification, which limits scalability, reproducibility, and the rapid diversification of linker architectures.

Researchers developed a novel solid-phase protocol for synthesizing tetraDVP (tetra-divinylpyrimidine) linkers, designed to simultaneously rebridge all four interchain disulfide bonds of native IgG1 and IgG4 antibodies. The multistep workflow involves solution-phase intermediate synthesis, solid-phase assembly on resin, polyethylene glycol elongation, installation of divinylpyrimidine warheads, and mild cleavage conditions. This method enables the controlled installation of functional payloads such as peptides, drugs, or protein tags with a precise payload-to-antibody ratio, creating diverse antibody conjugates.

The new solid-phase protocol for tetraDVP linkers significantly improves upon previous solution-phase routes, demonstrating enhanced yield, scalability, and reproducibility in linker production. This robust synthetic strategy enables the rapid generation of diverse antibody conjugates with controlled payload-to-antibody ratios, crucial for therapeutic efficacy. The protocol is designed for site-selective bioconjugation, ensuring that the native function of the antibody is preserved.

This approach provides the only reported strategy for conjugating a single payload to a native antibody without the need for chromatographic purification or genetic/glycan engineering. The complete procedure can be performed in approximately ~2 weeks, providing a versatile platform for accessing tetraDVP linkers bearing a variety of functional handles for subsequent antibody conjugation.