C. Boeckler et al., IMMUNOGENICITY OF NEW HETEROBIFUNCTIONAL CROSS-LINKING REAGENTS USED IN THE CONJUGATION OF SYNTHETIC PEPTIDES TO LIPOSOMES, Journal of immunological methods, 191(1), 1996, pp. 1-10
We have investigated the immunogenicity of six thiol-reactive heterobi
functional cross-linking reagents that permit the conjugation of cyste
ine carrying peptides to the surface of liposome containing monophosph
oryl lipid A. Such constructs elicit an immune response against short
synthetic peptides and our aim was to find the least immunogenic linke
rs to limit potential carrier-induced epitopic suppression. For that p
urpose the properties of three new polyoxyethylene linkers of differen
t lengths and thiol-reactive moieties (maleimide, bromoacetyl, dithiop
yridine) were compared to known derivatives obtained by reacting the c
lassical reagents SMPB and SPDP or N-succinimidyl bromoacetate with ph
osphatidylethanolamine. The least immunogenic linkers were the bromoac
etate derivatives whereas those containing a maleimide group evoked a
significant anti-linker immune response. In addition, using IRGERA as
a model peptide, we found that all six liposomal constructs strongly e
licited the production of anti-peptide IgG antibodies. This immune res
ponse was therefore independent of the length of the linkers (ranging
between 0.3 and 1.6 nm) and of the nature of the linkage between the p
eptide and the thiol-reactive moieties of the cross-linkers, i.e. stab
le thioether or bio-reducible disulfide bonds.