Tyrosinase-Mediated Synthesis of Nanobody–Cell Conjugates

A convenient enzymatic
strategy is reported for the modification
of cell surfaces. Using a tyrosinase enzyme isolated from Agaricus bisporus, unique tyrosine residues introduced at
the C-termini of nanobodies can be site-selectively oxidized to reactive o-quinones. These reactive intermediates undergo rapid modification
with nucleophilic thiol, amine, and imidazole residues present on
cell surfaces, producing novel nanobody–cell conjugates that
display targeted antigen binding. We extend this approach toward the
synthesis of nanobody–NK cell conjugates for targeted immunotherapy
applications. The resulting NK cell conjugates exhibit targeted cell
binding and elicit targeted cell death.