Antibody peptides

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Introduction
In bispecific molecules, the functional portions
targeting antigens include not only antibodies
but also some small drugs or peptides.
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Introduction
In BsAb repertoire, antibody-peptide conjugates,
also referred to as chemically programmed
antibodies (cpAbs), are a novel class of
pharmaceuticals utilizing small molecules as the
navigator instead of mAb. As therapeutic agents,
mAbs and peptides have their merits. Over the
past two decades, mAbs have become high
successful pharmaceuticals. A large number of
mAbs have been approved by FDA or/and EMA and
some are in phase III clinical trials.
The reasons behind the boom of mAbs include their
high affinity and specificity for antigens, their
large size enabling the prolonged half-life and
the Fc-mediated effector functions of mAbs with
Fc portion. By contrast, peptides also have high
affinity with unlimited access to almost all
niches of cells, meanwhile they are easier to
manufacture. Antibody-peptides conjugates combine
the advantages of mAbs and small molecules.
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Antibody-peptides conjugates
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Antibody-peptides conjugates
The antigen binding of conventional mAbs relies
on the virtue of six CDRs. While in chemically
programmed antibodies, peptides are responsible
for the antigen binding, which is
site-specifically and can covalently linked to
the antibody scaffold by the approach of
chemical programming. The antibody scaffold
equips the peptides with the long half-life,
Fc-mediated effector functions and bivalence of
conventional mAbs.
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Antibody-peptides conjugates
The scaffold antibody may be IgGs or fragments.
And the pharmacophores can also be
peptidomimetics, DNA/RNA aptamer or other small
molecules. The conjugation of the pharmacophores
with the scaffold antibody requires unique
reactivity centers. Up to now, there are mainly
three reactivity centers engineered C-terminal
selenocysteine (U), N-terminal cysteine (C)
residues and lysine (K) residue in the paratope.
Moreover, the scaffold antibody augments the
ability to interfere with ligand-receptor
interactions. To construct an intact
antibody-peptide conjugates, four elements are
needed a scaffold antibody, a peptide
pharmacophore, a reactive group and a linker
spacing pharmacophore and reactive group.
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