RESUMO
Advances have been made in the development of vaccines based on synthetic peptides and polypeptides representing tumor-associated antigens and protective epitopes of viruses and parasites. Advances within the past year include the design of vaccines based on artificial proteins, for example multiantigen peptides, branched polypeptides, fusion and recombinant peptides, as well as single T cell epitopes and tumor antigen peptides. Although peptide vaccines are not in use as yet, their potential is being explored.
Assuntos
Peptídeos/síntese química , Engenharia de Proteínas , Vacinas Sintéticas , Vacinas contra a AIDS/síntese química , Animais , Vacinas Anticâncer/síntese química , Portadores de Fármacos , Desenho de Fármacos , Humanos , Vacinas contra Influenza/síntese química , Vacinas Antimaláricas/síntese química , Esquistossomose/prevenção & controle , VírusRESUMO
Influenza infections may cause serious morbidity, as well as mortality in the elderly. In the present study we vaccinated old and young mice of two strains with three synthetic recombinant constructs (Levi and Arnon, 1995. In: Chanock, R.M. et al. (Eds.), Vaccines 95. CSHL Press, New York, pp. 311-316) and examined their capacity to eliminate a challenge of virus. Virus clearance from the lungs in the aged was very efficient, although the immune response in the aged was comparatively reduced. The data demonstrate that an intranasal administration of peptide-based anti-influenza vaccine without any adjuvant can be efficient and protective in old mice. Further studies are needed to determine whether such constructs will provide an effective vaccine for elderly human subjects.
Assuntos
Envelhecimento/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/prevenção & controle , Vacinas Sintéticas/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Antivirais/imunologia , Formação de Anticorpos , Embrião de Galinha , Citocinas/biossíntese , Humanos , Vírus da Influenza A/imunologia , Influenza Humana/patologia , Pulmão/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Fragmentos de Peptídeos/imunologia , Linfócitos TRESUMO
In our previous studies on the development of synthetic peptide-based vaccines, we have evaluated flagellin from a Salmonella typhi vaccine strain as a carrier molecule for synthetic peptides derived from the influenza virus. The results indicated that the use of recombinant flagella, expressing defined influenza epitopes, is adequate for induction of protection against a challenge infection. It is of importance to show that previous exposure to the carrier does not induce suppression of the response to such vaccine. In the present study we demonstrate that the protective effect is not impaired by pre-immunization with either the carrier flagellin molecule alone or with the intact salmonella. The immune response was manifested both by the level of antibodies produced and by a proliferative cellular response, as well as by an efficient protection of the mice from a sub-lethal challenge infection. Since prior exposure to the carrier did not result in immune suppression, we conclude that Salmonella flagellin is a suitable carrier for synthetic peptide based vaccines.
Assuntos
Flagelina/imunologia , Vacinas contra Influenza/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Salmonella typhi/imunologia , Vacinas Sintéticas/imunologia , Administração Intranasal , Sequência de Aminoácidos , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Antivirais/sangue , Ensaio de Imunoadsorção Enzimática , Epitopos/genética , Epitopos/imunologia , Flagelina/genética , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/genética , Pulmão/virologia , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/virologia , Salmonella typhi/genética , Fatores de Tempo , Vacinação , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/genéticaRESUMO
Previous studies have shown that a recombinant vaccine expressing four highly conserved influenza virus epitopes has a potential for a broad spectrum, cross-reactive vaccine; it induced protection against H1, H2 and H3 influenza strains. Here, we report on the evaluation of an epitope-based vaccine in which six conserved epitopes, common to many influenza virus strains are expressed within a recombinant flagellin that serves as both a carrier and adjuvant. In an HLA-A2.1 transgenic mice model, this vaccine induced both humoral and cellular responses and conferred some protection against lethal challenge with the highly pathogenic H5N1 avian influenza strain. Hence, it is expected to protect against future strains as well. The data presented, demonstrate the feasibility of using an array of peptides for vaccination, which might pave the way to an advantageous universal influenza virus vaccine that does not require frequent updates and/or annual immunizations.
Assuntos
Epitopos/imunologia , Virus da Influenza A Subtipo H5N1/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/prevenção & controle , Adjuvantes Imunológicos/farmacologia , Animais , Anticorpos Antivirais/sangue , Células Cultivadas , Feminino , Flagelina/imunologia , Humanos , Influenza Humana/imunologia , Interferon gama/biossíntese , Células Matadoras Naturais/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos ICR , Camundongos Transgênicos , Coelhos , Proteínas Recombinantes/imunologiaRESUMO
Synthetic recombinant vaccines are constructs in which a synthetic oligonucleotide coding for a protective epitope is inserted into an adequate gene for expression of the epitope. We report the results obtained using recombinant flagella of Salmonella vaccine strain expressing epitopes of influenza virus or of the parasite Schistosoma mansoni. In the case of influenza virus, three conserved epitopes of the haemagglutinin and the nucleoprotein of the virus inducing B- and T-cell immune response, were expressed and the flagella were used for intranasal immunization without any adjuvant. Both humoral and cellular immune responses specific to the virus induced in mice cross-strain long-term protection against challenge infection. Aged mice were also able to resist infection. For the design of a human influenza vaccine, epitopes recognized by the HLAs prevalent in Caucasian populations were used, and the resulting vaccine was evaluated in human/mouse radiation chimaera in which human PBMC are functionally engrafted. The vaccinated mice demonstrated efficient clearance of the virus after challenge and resistance to lethal infection. In the case of the parasitic disease schistosomiasis, a 14-residue peptide denoted 9B peptide 1 was expressed in the flagella. Intranasal vaccination of mice with this construct, without the use of adjuvant, resulted in 40% protection against challenge infection.
Assuntos
Antivirais/química , Peptídeos/química , Schistosoma mansoni/imunologia , Vacinas Sintéticas/química , Animais , Antivirais/farmacologia , Vírus da Influenza A/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Infecções por Orthomyxoviridae/prevenção & controle , Peptídeos/farmacologia , Salmonella/imunologia , Infecções por Salmonella/prevenção & controle , Esquistossomose/prevenção & controle , Vacinas Sintéticas/farmacologiaRESUMO
Influenza virus is characterized by frequent and unpredictable changes of the surface glycoproteins which enable the virus to escape the immune system. Approved vaccines which consist of the whole virus or the surface glycoproteins fail to induce broad specificity protection. We have previously reported that a peptide-based experimental recombinant vaccine which includes conserved epitopes of B and T lymphocytes was efficient in mice, leading to cross-strain, long-term protection. In the present study, this approach was adapted for the design of a human vaccine, based on epitopes recognized by the prevalent HLAs. These epitopes were expressed in Salmonella flagellin and tested for their efficacy in human/mouse radiation chimera in which human peripheral blood mononuclear cells (PBMC) are functionally engrafted. The vaccinated mice demonstrated clearance of the virus after challenge and resistance to lethal infection. The production of virus-specific human antibodies was also higher in this group. Control groups of either non-vaccinated, or vaccinated mice which had not been engrafted with the human PBMC, did not exhibit the protective immune response. FACS analysis showed that most human cells in the transplanted mice are CD8(+) and CD4(+). Hence, it may be concluded: (i) that the protection involves cellular mechanisms, but is most probably accomplished without direct lysis of influenza-infected pulmonary cells by cytotoxic T lymphocytes, but rather via a cytokine-mediated mechanism, (ii) that the human/mouse radiation chimera model may be of some value in the investigation of new vaccines, as an additional tool prior to clinical trials, and (iii) that the synthetic recombinant vaccine can induce a response in the human immune system and confers protection against influenza infection. Further investigation is needed to establish the efficacy of such a peptide vaccine in human subjects.
Assuntos
Vírus da Influenza A/imunologia , Vírus da Influenza B/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/prevenção & controle , Quimera por Radiação/imunologia , Administração Intranasal , Sequência de Aminoácidos , Animais , Anticorpos Antivirais/biossíntese , Humanos , Influenza Humana/imunologia , Influenza Humana/virologia , Pulmão/virologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos NOD , Camundongos SCID , Dados de Sequência Molecular , Vacinas de Produtos Inativados/imunologiaRESUMO
Schistosomiasis is the cause of a chronic debilitating disease which accounts for significant mortality and morbidity every year, especially in tropical and subtropical areas. An epitope derived from the protective surface protein 9B-Ag of Schistosoma mansoni, designated 9B peptide-1, was previously showed to be protective in mice when conjugated to bovine serum albumin and administered subcutaneously in complete Freund's adjuvant. In this work, this protective peptide was expressed in the flagellin of a Salmonella vaccine strain, and the isolated recombinant flagella were used for immunization of mice. Since during the invasion of the parasite into the host the schistosomula migrate first to the lungs, the intranasal route of administration was employed in order to halt the parasite at an early stage of the infection. Such intranasal immunization with this peptide expressed in flagellin, without the addition of adjuvants, resulted in a significant humoral response and also led to protection against challenge infection, manifested as a reduction of the worm burden by an average of 42%.