Induction of an Antigen-Specific CTL Response by a Conformationally Biased Agonist of Human C5a Anaphylatoxin as a Molecular Adjuvant

Abstract

A conformationally biased decapeptide agonist of human C5a anaphylatoxin (YSFKPMPLaR) was used as a molecular adjuvant in stimulating an Ag-specific CTL response against murine P815S target cells expressing an Ld-restricted CTL epitope of the hepatitis B surface Ag (HBsAg). Groups of BALB/c mice (H-2d) were immunized with aqueous solutions of the HBsAg CTL epitopes (IPQSLDSWWTSL and IPQSLDSWWTSLRR); the C5a agonist (YSFKPMPLaR); the C5a agonist and HBsAg CTL epitopes admixed (IPQSLDSWWTSL and IPQSLDSWWTSLRR + YSFKPMPLaR); the C5a-active, HBsAg CTL epitope-C5a agonist constructs (IPQSLDSWWTSLYSFKPMPLaR, IPQSLDSWWTSLRRYSFKPMPLaR, and IPQSLDSWWTSLRVRRYSFPMPLaR); a C5a-inactive, reverse-moiety construct (YSFKPMPLaRRRIPQSLDSWWTSL); and a C5a-attenuated, carboxyl-terminal-blocked construct (IPQSLDSWWTSLRRYSFKPMPLaRG). Ag-specific CD8+ CTL responses were observed after the secondary boost in the absence of any added adjuvant only in mice that were immunized with C5a-active contructs, IPQSLDSWWTSLRRYSFKPMPLaR and IPQSLDSWWTSLRVRRYSFKPMPLaR. These two C5a-active immunogens contained potential subtilisin-sensitive linker sequences between the HBsAg CTL epitope and the C5a agonist; i.e., a double-Arg (RR) and a furin protease sensitive sequence (RVRR). The introduction of these potentially cleavable sequences may be a method of increasing the likelihood of liberating the CTL epitope from the C5a agonist by intracellular proteases, thereby facilitating entry of the epitope into Ag-processing pathways via an exogenous route.

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

“…The immunologic results presented in this study are consistent with those observed with an EP54-containing vaccine to nicotine [15] and with a mechanism we proposed earlier to describe the molecular adjuvant properties of EP54 (YSFKPMPLaR) and its ability to induce Ag-specific Ab and cell-mediated immune responses [20][21][22][23][24]. Briefly, EP54 selectively interacts with C5aRs on antigen presenting cells (especially DCs) and induces the release of Th1 cytokines.…”

“…EP54 retains C5a-like immune stimulatory properties, but with significantly reduced C5a-like inflammatory properties [17][18][19][20]. The role of the molecular adjuvant EP54 in these vaccines is to target covalently attached Ags to and activate the Ag processing and presentation capacity of C5a receptor-bearing antigen presenting cells [21][22][23], particularly dendritic cells (DCs) [24].…”

Production of recombinant C5a from rainbow trout (Oncorhynchus mykiss): role in leucocyte chemotaxis and respiratory burst

“…C5a has also been demonstrated to have an influence in adaptive immune responses. In this regard, it has been shown to act as an adjuvant by enhancing the humoral response [15] and by promoting antigenspecific cytotoxic (CTL) responses [16].…”

Epidermal Powder Immunization Induces both Cytotoxic T-Lymphocyte and Antibody Responses to Protein Antigens of Influenza and Hepatitis B Viruses

“…There are a large number of successful animal studies; however, to date there are few human studies showing the successful induction of humoral and cellular immune responses (45). Adjuvants have been used to induce CTL responses to subunit or inactivated viruses (28,34,50,55). However, the discovery of adjuvants that are both safe and effective has proven to be a great challenge.…”