RESUMO
Streptococcus pyogenes causes severe invasive infections: the post-streptococcal sequelae of acute rheumatic fever (RF) and rheumatic heart disease (RHD), acute glomerulonephritis, and uncomplicated pharyngitis and pyoderma. Efforts to produce a vaccine against S. pyogenes began several decades ago, and different models have been proposed. Here, we describe the methodology used in the development of a new vaccine model, consisting of both T and B protective epitopes constructed as synthetic peptides and recombinant proteins. Two adjuvants were tested in an experimental inbred mouse model: a classical Freund's adjuvant and a new adjuvant (AFCo1) that induces mucosal immune responses and is obtained by calcium precipitation of a proteoliposome derived from the outer membrane of Neisseria meningitides B. The StreptInCor vaccine epitope co-administrated with AFCo1 adjuvant induced mucosal (IgA) and systemic (IgG) antibodies as preferential Th1-mediated immune responses. No autoimmune reactions were observed, suggesting that the vaccine epitope is safe.
Assuntos
Desenho de Fármacos , Vacinas Estreptocócicas/imunologia , Streptococcus pyogenes/imunologia , Sequência de Aminoácidos , Animais , Feminino , Imunidade nas Mucosas/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Vacinas Estreptocócicas/administração & dosagem , Vacinas Estreptocócicas/síntese química , Streptococcus pyogenes/efeitos dos fármacosRESUMO
The development of 16 self-adjuvanting group A streptococcal vaccine candidates, composed of (i) a universal helper T-cell epitope (P25), (ii) a target GAS B-cell epitope (J14), and (iii) a lipid moiety, is described. Systemic J14-specific IgG antibodies were detected following subcutaneous immunization of BALB/c (H-2 (d)) mice with each construct without the need for an additional adjuvant. The effect of changing the order of P25, J14, and lipid moiety attachment or incorporation of P25 and J14 into a lipid-core peptide system on antibody titers was assessed. The point of lipid moiety attachment had the greatest influence on systemic J14-specific IgG antibody titers. Overall, the best vaccines featured a C-terminal lipid moiety, conjugated through a lysine residue to P25 at the N-terminus, and J14 on the lysine side chain.
Assuntos
Aminoácidos/química , Lipídeos/química , Vacinas Estreptocócicas/síntese química , Streptococcus pyogenes/imunologia , Vacinas de Subunidades Antigênicas/síntese química , Animais , Epitopos de Linfócito B , Epitopos de Linfócito T , Feminino , Imunoglobulina G/sangue , Camundongos , Camundongos Endogâmicos BALB C , Vacinas Estreptocócicas/imunologia , Relação Estrutura-Atividade , Vacinas de Subunidades Antigênicas/imunologia , Vacinas Sintéticas/imunologiaRESUMO
The aim of this study was to investigate methods for the synthesis of highly pure, well-characterized analogues of the lipid core peptide (LCP) system. Difficulties synthesizing and purifying conventional LCP systems have led to the requirement for a technique to produce highly pure, LCP-based vaccines for potential use in human clinical trials. The current study describes methods for the attachment of lipophilic adjuvants onto multi-epitopic peptide vaccines. Described is the synthesis, using native chemical ligation, of a highly pure, tri-epitopic, group A streptococcal (GAS) lipopeptide vaccine candidate. Intranasal immunization of the described tri-epitopic GAS lipopeptide with the mucosal adjuvant cholera toxin B subunit induced high serum IgG antibody titers specific for each of the incorporated peptide epitopes.