Development and Comparison of Different Peptide IgG Conjugates for the Treatmentof Gram-Negative Sepsis

摘要

Work over the trimester focused on developing LBP peptides with higher bindingaffinities, defining the best BPI binding protein (BPI) peptide sequence, generating peptide-Ig conjugates with this sequence, developing an assay for opsinophagocytosis, and starting work on the evaluation of the pharmacokinetics of the conjugates. We synthesized overlapping peptides of the published sequence of BPI, and identified BPI85-99 as the optimal binding sequence. As in the LBP peptide studies reported earlier, placement of a terminal cysteine on the peptide increased activity. Conjugates of BPI85-99-IgG were generated using SMPT as a linker, and BPI85-99-IgG was found to bind LPS slightly better than BPI85-99-IgG. A opsinophagocytosis assay was developed. Clearance studies were started; in preliminary studies a peptide-IgO conjugate based on a CAPi8 peptide with high LPS binding activity was studied. These experiments indicated that the Ti/2 of this conjugate was greater than 24 hours. Further studies using these assay systems are planned when larger amounts of the LBP/BPI conjugates are available.