Highly Immunogenic and Totally Synthetic Lipopeptides as Self-Adjuvanting Immunocontraceptive Vaccines

Abstract

In this study, we describe the synthesis of various lipopeptides based on the sequence of luteinizing hormone-releasing hormone (LHRH) and report on their abilities to induce Abs against this “self” hormone when inoculated into mice in the absence of additional adjuvant. The peptides consisted of a colinear CD4+ T helper cell epitope from the L chain of influenza virus hemagglutinin and LHRH, which has B cell epitopes but no T cell epitopes present in its sequence. Lipids were attached either at the N terminus or between the T cell epitope and LHRH, in the approximate center of the peptide. The lipopeptide constructs displayed different solubilities and immunological properties that depended not only on the lipid content but also on the position of attachment of the lipids. Some of these constructs were highly immunogenic, inducing high titers of Ab, which were capable of efficiently sterilizing female mice when administered in saline by s.c. or intranasal routes. The most effective vaccines were highly soluble, contained the dipalmitoyl-S-glyceryl cysteine moiety, and had this lipid attached at the center of the molecule. The relative ability of the lipopeptides to induce an Ab response in the absence of external adjuvant was reflected by their ability to up-regulate the surface expression of MHC class II molecules on immature dendritic cells. These results demonstrate that the composition and position within peptide vaccines of self-adjuvanting lipid groups can influence the ability to induce the maturation of dendritic cells and, in turn, the magnitude of the resulting Ab response.

Herpes Simplex Virus Antigens Directly Activate NK Cells via TLR2, Thus Facilitating Their Presentation to CD4 T Lymphocytes

“…gD2-24-4 and -30-5 were synthesized using Fmoc chemistry, as previously described (42). The amino acid sequences of the immunodominant CD4 T lymphocyte epitopes in gD2 were QQGVTVDSIGML and PEDPED-SALLED for peptides gD2-24-4 and gD2-30-5, respectively.…”

“…The amino acid sequences of the immunodominant CD4 T lymphocyte epitopes in gD2 were QQGVTVDSIGML and PEDPED-SALLED for peptides gD2-24-4 and gD2-30-5, respectively. The two Pam2Cys-conjugated gD peptides (Pam2Cys-gD2-24-4 and Pam2Cys-gD2-30-5) were synthesized by covalently coupling of Pam2Cys lipid moiety through two serine residues to each parental peptide (42). For carboxyfluorescein conjugation onto gD2-30-5 and Pam2Cys-gD2-30-5, the N-terminal of the Fmoc group was removed following the last acylation reaction, and 5(6)-carboxyfluorescein (Fluka Biochmika) was then coupled to the exposed amino group using a 4-fold molar excess in the presence of equimolar amounts of O-benzotriazole-N,N,N9,N9-tetramethyluronium-hexafluorophosphate (Merck) and 1-hydroxybenzotriazole (Merck) and a 1.5-fold excess of diisopropylethylamine (Fluka Biochmika) for 4 h. All peptides were cleaved from the solid support, and side chain protecting groups were simultaneously removed before being purified and characterized, as described previously (42).…”

“…In general, short peptides are weak immunogens, so they need to be administered with adjuvants. To enhance the immunogenicity of our gD2 peptides, they were conjugated to dipalmitoyl-S-glyceryl cysteine (Pam2Cys) (42), which binds specifically to and stimulates via TLR2 and its heterodimeric partner TLR6 and induces maturation in DCs (43-46) (some HSV strains also target TLR2 naturally).…”

Synthesis, Characterization and Immunological Evaluation of Self‐Adjuvanting Group A Streptococcal Vaccine Candidates Bearing Various Lipidic Adjuvanting Moieties

“…[24] The final compound, 1d, contained a lipidic adjuvant that bears close structural resemblance to the well-known 2,3-dipalmitoyl-Sglycerylcysteine (Pam2Cys) lipidic adjuvanting moiety ( Figure 2). [25][26][27] The dipalmitoyl serine (DPS) adjuvant can be easily synthesized as an enantiomerically pure moiety, using standard solid phase peptide synthesis (SPPS), from readily available starting materials. Recently, we demonstrated that the DPS adjuvanting moiety showed strong binding affinity to the extracellular domain of the TLR2.…”

Hyperadrenocorticism in Ferrets

“…21,37,46,73 Depending on the species, these vaccines aim at contraception, the prevention of boar taint, or the control of hormone-dependent cancers, including breast and prostate cancers. In ferrets, use of a GnRH vaccine would serve two goals: inactive gonads in both sexes in combination with low plasma concentrations of gonadotropic hormones.…”