A Peptide Carrier with a Built-In Vaccine Adjuvant:  Construction of Immunogenic Conjugates

Abstract

A multifunctional carrier combining B/T cell epitopes (i), a built-in vaccine adjuvant (ii), and a universal T cell epitope (iii) for the construction of potent and specific immunogenic conjugates is presented. The IL-1beta(163-171) fragment known to reproduce the immunostimulatory and adjuvant effects of the whole IL-1beta without possessing any of the pro-inflammatory properties of IL-1beta was covalently anchored to the N-terminus of the Sequential Oligopeptide Carrier, SOC(n), formed by the repeating tripeptide unit Lys-Aib-Gly. A promiscuous T cell epitope derived from the tetanus toxin, TT(593-599), was also positioned in the carboxy terminus of SOC(n) as a universal immunogen to provide broad immunogenicity. Selected B/T cell epitopes from the Sm and La/SSB autoantigens, against which is directed the humoral autoimmunity in patients with systemic lupus erythematosus and Sjögren's Syndrome, respectively, were coupled to the Lys-N(epsilon)H2 groups of the carrier, and the formulated constructs were administered in animals following the conventional immunization protocol of complete/incomplete Freund's adjuvant. The induced immune responses were compared with that produced when the Sm- and La/SSB-reconstituted immunogenic conjugates were injected alone. High titers of specific antibodies recognizing the priming construct, as well as the cognate autoantigen, were obtained when administered alone without the assistance of Freund's adjuvant. It is concluded that our approach provides the conceptual and experimental framework for the development of multifunctional immunogenic conjugates eliciting enhanced, specific, and prolonged humoral response for usage as human vaccine candidates.

Immune responses to methamphetamine by active immunization with peptide-based, molecular adjuvant-containing vaccines

“…2 indicates an 80% inhibition of the METH-positive rat serum in the presence of free methamphetamine, demonstrating Ab specificity to the drug. Vaccines 2 and 4 incorporated the T-cell epitope YSYFPSV from tetanus toxin (TT 593-599 ) as a component for generating CD4 + T-cell help in the production of anti-METH/meth Abs [25]. To determine the involvement of this T-cell help, T-cells from spleens of METH/meth-positive rats immunized with Vaccines 2 and 4 were isolated and incubated with BSA modified with METH or a vehicle control.…”

“…YSYFPSV is processed by DCs, presented in the context of MHC/HLA class II, and invokes CD4 + T-cell help to B cells for the production of Abs [25]. Thus, we reasoned that METH-YSYFPSV likewise would be processed and presented by DCs, particularly when targeted to and activated by EP54.…”

“…The use of TT 593-599 in these EP54-containing vaccines is attractive because it is well-characterized immunologically, is small and easy to synthesize, and has been used in other larger, peptidebased vaccines to invoke CD4 + T-cell help for B cells to generate Ag-specific Abs [25]. Also, it is possible that this CD4 + response in humans may be readily invoked with such TT/molecular adjuvantcontaining vaccines to meth since most people already have been immunized to tetanus.…”

“…The second vaccine component is a T-cell epitope from tetanus toxin TT 593-599 (YSYFPSV) [25], which was covalently attached to the N-terminus of EP54. This epitope was used to engage CD4 + helper T-cells in order to provide the necessary T-cell help for the Ab-producing B cells during epitope/hapten presentation by DCs activated by EP54.…”

Robust immune responses elicited by a fully synthetic three-component vaccine

“…In addition, foreign carrier proteins such as keyhole limpet hemocyanin (KLH) and bovine serum albumin (BSA) and the linker that attach the saccharides to the carrier protein can elicit strong B-cell responses, which may lead to the suppression of antibody responses against the carbohydrate epitope 5,6 . It is clear that the successful development of carbohydrate-based cancer vaccines requires novel strategies for the more efficient presentation of tumor-associated carbohydrate epitopes to the immune system, resulting in a more efficient class switch to IgG antibodies [7][8][9][10][11][12][13][14][15][16][17] .…”