Effect of Conjugation with Polypeptide Carrier on the Enzymatic Degradation of Herpes Simplex Virus Glycoprotein D Derived Epitope Peptide

Abstract

Two conjugates with epitope peptide (278)LLEDPVGTVA (287) derived from glycoprotein D (gD-1) of Herpes simplex virus (HSV) were synthesized for analysis of the effect of conjugation on protection against enzymatic degradation. In this design, the turn-forming epitope core (281)DPVG (284) was positioned in the central part of the peptide and elongated by three amino acids from the native sequence at both termini. Conjugation was achieved by the introduction of amide bond or thioether linkage between the C-terminal of the HSV peptide and the side chain of four lysine residues of the oligotuftsin derivative used as carrier molecule. We compared the proteolytic stability of the conjugates in diluted human sera as well as in rat liver lysosomal preparation. The data obtained in lysosomal preparation at two pH values (pH 3.5 and 5.0) show that the type of covalent bond between the carrier and the epitope peptide had no significant effect, as compared to the stability of the free, unconjugated peptide. Based on the identification of degradation fragments by mass spectrometry we found marked differences in the lengths and amounts of oligopeptides obtained. In contrast, in 10% and 50% human serum the conjugation provided full protection against enzymatic hydrolysis over 96 h, while the free peptide was decomposed quickly.

Design, Synthesis, and In Vitro Activity of Novel Drug Delivery Systems Containing Tuftsin Derivatives and Methotrexate

“…No significant split in the oligotuftsin backbone could be detected, and the cleavage pattern did not change when the incubation time was increased from 15 min to 1 h. Our results suggested that the main cleavage site is between the Gly and Phe amino acid residues in the spacer sequence; thus, the drug can be released from the conjugates in the lysosomes. It is worth noting that the cleavage of the Ala-Cys bond in the lysosomal preparations was observed in the case of a conjugate of H-LLEDPVGTVAC-NH 2 (HSV epitope peptide) attached to the OT20 carrier through a thioether bond (39). On the basis of this similarity, we can hypothesize that peptides with Cys-amide at the C-terminus might provide a cleavage site for cathepsin B, which cannot be prevented by conjugation of Cys through thioether bond.…”

Synthesis and Antibody Recognition of Cyclic Epitope Peptides, Together with Their Dimer and Conjugated Derivatives Based on Residues 9−22 of Herpes Simplex Virus Type 1 Glycoprotein D

“…In addition, cyclization might enhance the stability of the peptide against enzymatic degradation. According to other results (37,38) by our group, one can assume that conjugated cyclic peptides might have increased stability in human serum compared to their linear versions. For this reason, in addition to compound 5 containing the linear epitope in the conjugate, compound 21 in which cyclic epitope was conjugated to OT20 carrier on its branch was selected for further development for the investigation of their immune response inducing potential.…”

Tuftsin derivatives of FITC, Tb–DOTA or Gd–DOTA as potential macrophage‐specific imaging biomarkers

“…These data show that the cells incubated with Gd-DOTA-tuftsin were magnetically labelled and detectable by MRI, tuftsin retaining its binding activity after being conjugated with Gd-complex, which confirms the targeting ability of the vectorized MRI probe. The peptide could be substantially more resistant to enzymatic degradation after linking with the Gd chelate (49,50), which may modify its in vivo biodistribution profile, rate and mode of clearance from the body, bioavailability and pharmacokinetics (51).…”