Study at the air/water interface of a hepatitis A N-acetylated and C-amidated synthetic peptide (AcVP3(110-121)-NH2) - I. Surface activity and insertion in lipid monolayers

Synthetic peptide vaccines are safer and cheaper than classical ones, but i mmunoresponse is usually lower. The early interaction of hepatitis A virus (HAV) with cells during the infection and immunological response processes is not as well-known as for other picornavirus. However, it seems that elec trostatic interactions have an important role in the fusion of HAV with cel l membranes. In order to gain more understanding in these processes, in the present work, we have studied the interactions of AcVP3110, a synthetic HA V peptide, an acetylated amidated derivative of the epitope VP3(110-121), w ith a neutral phospholipid (dipalmitoyl phosphatidylcholine), an anionic ph ospholipid (dipalmitoyl phosphatidylglycerol),and a cationic lipid (stearyl amine), using a monolayer technique. AcVP3110 showed higher surface activit y than the parent peptide, probably owing to its acyl moiety. Studies of th e kinetics at constant area of the peptide injected under monolayers of the lipids assayed showed only slight differences depending on the charge of t he lipid. On the other hand, when compression isotherms of these lipids on a subphase containing the peptide were performed, major interactions were f ound for stearylamine monolayers. Owing to the negative net charge of AcVP3 110, it is quite clear that electrostatic forces do have a role in the inte raction of this synthetic peptide with membranes, as has been seen with com plete HAV. (C) 2001 Academic Press.