Characterization of a multi-lipopeptides mixture used as an HIV-1 vaccine candidate

A multi-component vaccine has been defined, which contains six different sy nthetic 24- to 32-amino acid lipopeptides derived from the sequence of HIV- I proteins. The physicochemical properties of the lipopeptide components we re compatible with multi-dimensional analysis, using RP-HPLC, Edman sequenc ing, electrospray mass spectrometry, and 2D-NMR. Detailed analysis of the i mpurity profiles led to the detection and evaluation of the relative propor tions of most by-products: several contaminants resulted from the formation of acetylated fragments, transpeptidation reactions with succinimide or pi peridide formation, or methionine and/or tryptophan mono-oxidations. The fi rst batch to be produced underwent extensive pharmacotoxicological testings to confirm its safety; this vaccine candidate has now been used in phase I clinical trials. Despite the complexity of such multi-lipopeptide vaccines , our findings suggest the possibility of preparing a clear and precise ass ignment of by-products to toxicologically qualified impurities in the event uality of a future production of several successive batches. (C) 1999 Elsev ier Science Ltd. All rights reserved.