RESUMO
The lung is an important entry site for pathogens; its exposure to antigens results in systemic as well as local IgA and IgG antibodies. Here we show that intranasal administration of virus-like particles (VLPs) results in splenic B-cell responses with strong local germinal-center formation. Surprisingly, VLPs were not transported from the lung to the spleen in a free form but by B cells. The interaction between VLPs and B cells was initiated in the lung and occurred independently of complement receptor 2 and Fcγ receptors, but was dependent upon B-cell receptors. Thus, B cells passing through the lungs bind VLPs via their B-cell receptors and deliver them to local B cells within the splenic B-cell follicle. This process is fundamentally different from delivery of blood or lymph borne particulate antigens, which are transported into B cell follicles by binding to complement receptors on B cells.
Assuntos
Linfócitos B/imunologia , Linfócitos B/virologia , Vacinas de Partículas Semelhantes a Vírus/imunologia , Administração Intranasal , Transferência Adotiva , Animais , Anticorpos Antivirais/biossíntese , Antígenos Virais/administração & dosagem , Antígenos Virais/sangue , Movimento Celular/imunologia , Feminino , Imunoglobulina G/biossíntese , Pulmão/imunologia , Pulmão/virologia , Camundongos , Camundongos Endogâmicos C57BL , Receptores de Antígenos de Linfócitos B/imunologia , Receptores de Complemento 3d/imunologia , Receptores de IgG/imunologia , Baço/imunologia , Baço/virologia , Vacinas de Partículas Semelhantes a Vírus/administração & dosagem , Vacinas de Partículas Semelhantes a Vírus/sangueRESUMO
A vaccine protecting against all influenza strains is a long-sought goal, particularly for emerging pandemics. As previously shown, vaccines based on the highly conserved extracellular domain of M2 (M2e) may protect against all influenza A strains. Here, we demonstrate that M2e-specific monoclonal antibodies (mAbs) protect mice from a lethal influenza infection. To be protective, antibodies had to be able to bind to Fc receptors and fix complement. Furthermore, mAbs of IgG2c isotype were protective in mice, while antibodies of identical specificity, but of the IgG1 isotype, failed to prevent disease. These findings readily translated into vaccine design. A vaccine targeting M2 in the absence of a toll-like receptor (TLR) 7 ligand primarily induced IgG1, whilst the same vaccine linked to a TLR7 ligand yielded high levels of IgG2c antibodies. Although both vaccines protected mice from a lethal challenge, mice treated with the vaccine containing a TLR7 ligand showed significantly lower morbidity. In accordance with these findings, vaccination of TLR7(-/-) mice with a vaccine containing a TLR7 ligand did not result in protection from a lethal challenge. Hence, the innate immune system is required to direct isotype switching toward the more protective IgG2a/c antibodies.
Assuntos
Anticorpos Antivirais/imunologia , Imunoglobulina G/imunologia , Vírus da Influenza A/imunologia , Vacinas contra Influenza/imunologia , Glicoproteínas de Membrana/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Transdução de Sinais/imunologia , Receptor 7 Toll-Like/imunologia , Animais , Anticorpos Monoclonais Murinos/imunologia , Anticorpos Monoclonais Murinos/farmacologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/genética , Humanos , Imunidade Inata/efeitos dos fármacos , Imunidade Inata/genética , Switching de Imunoglobulina/efeitos dos fármacos , Switching de Imunoglobulina/genética , Imunoglobulina G/sangue , Imunoglobulina G/genética , Vírus da Influenza A/genética , Vírus da Influenza A/metabolismo , Vacinas contra Influenza/farmacologia , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Knockout , Infecções por Orthomyxoviridae/sangue , Infecções por Orthomyxoviridae/genética , Infecções por Orthomyxoviridae/imunologia , Pandemias , Transdução de Sinais/genética , Receptor 7 Toll-Like/genética , Receptor 7 Toll-Like/metabolismo , VacinaçãoRESUMO
Humoral immune responses are thought to be enhanced by complement-mediated recruitment of the CD21-CD19-CD81 coreceptor complex into the B cell antigen receptor (BCR) complex, which lowers the threshold of B cell activation and increases the survival and proliferative capacity of responding B cells. To investigate the role of the CD21-CD35 complement receptors in the generation of B cell memory, we analyzed the response against viral particles derived from the bacteriophage Qbeta in mice deficient in CD21-CD35 (Cr2(-/-)). Despite highly efficient induction of early antibody responses and germinal center (GC) reactions to immunization with Qbeta, Cr2(-/-) mice exhibited impaired antibody persistence paralleled by a strongly reduced development of bone marrow plasma cells. Surprisingly, antigen-specific memory B cells were essentially normal in these mice. In the absence of CD21-mediated costimulation, Qbeta-specific post-GC B cells failed to induce the transcriptional regulators Blimp-1 and XBP-1 driving plasma cell differentiation, and the antiapoptotic protein Bcl-2, which resulted in failure to generate the precursor population of long-lived plasma cells residing in the bone marrow. These results suggest that complement receptors maintain antibody responses by delivery of differentiation and survival signals to precursors of bone marrow plasma cells.
Assuntos
Células da Medula Óssea/imunologia , Proteínas de Ligação a DNA/biossíntese , Regulação da Expressão Gênica/imunologia , Proteínas Nucleares/biossíntese , Plasmócitos/imunologia , Receptores de Complemento 3d/imunologia , Proteínas Repressoras/biossíntese , Fatores de Transcrição/biossíntese , Allolevivirus/imunologia , Animais , Anticorpos Antivirais/imunologia , Formação de Anticorpos/genética , Formação de Anticorpos/imunologia , Antígenos CD , Antígenos Virais/imunologia , Apoptose/genética , Apoptose/imunologia , Células da Medula Óssea/citologia , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Sobrevivência Celular/genética , Sobrevivência Celular/imunologia , Proteínas de Ligação a DNA/imunologia , Regulação da Expressão Gênica/genética , Camundongos , Camundongos Knockout , Proteínas Nucleares/imunologia , Fator 1 de Ligação ao Domínio I Regulador Positivo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/imunologia , Receptores de Antígenos de Linfócitos B/genética , Receptores de Antígenos de Linfócitos B/imunologia , Receptores de Complemento 3d/genética , Fatores de Transcrição de Fator Regulador X , Proteínas Repressoras/imunologia , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Fatores de Transcrição/imunologia , Proteína 1 de Ligação a X-BoxRESUMO
The mechanisms regulating systemic and mucosal IgA responses in the respiratory tract are incompletely understood. Using virus-like particles loaded with single-stranded RNA as a ligand for TLR7, we found that systemic vs mucosal IgA responses in mice were differently regulated. Systemic IgA responses following s.c. immunization were T cell independent and did not require TACI or TGFbeta, whereas mucosal IgA production was dependent on Th cells, TACI, and TGFbeta. Strikingly, both responses required TLR7 signaling, but systemic IgA depended upon TLR7 signaling directly to B cells whereas mucosal IgA required TLR7 signaling to lung dendritic cells and alveolar macrophages. Our data show that IgA switching is controlled differently according to the cell type receiving TLR signals. This knowledge should facilitate the development of IgA-inducing vaccines.
Assuntos
Células Dendríticas/imunologia , Imunoglobulina A/biossíntese , Pulmão/imunologia , Macrófagos Alveolares/imunologia , Mucosa/imunologia , RNA/imunologia , Animais , Glicoproteínas de Membrana , Camundongos , Camundongos Knockout , Linfócitos T Auxiliares-Indutores , Receptor 7 Toll-Like , Fator de Crescimento Transformador beta , Proteína Transmembrana Ativadora e Interagente do CAMLRESUMO
Although current influenza vaccines are effective in general, there is an urgent need for the development of new technologies to improve vaccine production timelines, capacities and immunogenicity. Herein, we describe the development of an influenza vaccine technology which enables recombinant production of highly efficient influenza vaccines in bacterial expression systems. The globular head domain of influenza hemagglutinin, comprising most of the protein's neutralizing epitopes, was expressed in E. coli and covalently conjugated to bacteriophage-derived virus-like particles produced independently in E.coli. Conjugate influenza vaccines produced this way were used to immunize mice and found to elicit immune sera with high antibody titers specific for the native influenza hemagglutinin protein and high hemagglutination-inhibition titers. Moreover vaccination with these vaccines induced full protection against lethal challenges with homologous and highly drifted influenza strains.
Assuntos
Vírus da Influenza A Subtipo H1N1/imunologia , Vacinas contra Influenza/imunologia , Potência de Vacina , Animais , Anticorpos Antivirais/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Humanos , Imunização , Vírus da Influenza A Subtipo H1N1/genética , Vacinas contra Influenza/biossíntese , Vacinas contra Influenza/genética , CamundongosRESUMO
Influenza pandemics can spread quickly and cost millions of lives; the 2009 H1N1 pandemic highlighted the shortfall in the current vaccine strategy and the need for an improved global response in terms of shortening the time required to manufacture the vaccine and increasing production capacity. Here we describe the pre-clinical assessment of a novel 2009 H1N1 pandemic influenza vaccine based on the E. coli-produced HA globular head domain covalently linked to virus-like particles derived from the bacteriophage Qß. When formulated with alum adjuvant and used to immunize mice, dose finding studies found that a 10 µg dose of this vaccine (3.7 µg globular HA content) induced antibody titers comparable to a 1.5 µg dose (0.7 µg globular HA content) of the licensed 2009 H1N1 pandemic vaccine Panvax, and significantly reduced viral titers in the lung following challenge with 2009 H1N1 pandemic influenza A/California/07/2009 virus. While Panvax failed to induce marked T cell responses, the novel vaccine stimulated substantial antigen-specific interferon-γ production in splenocytes from immunized mice, alongside enhanced IgG2a antibody production. In ferrets the vaccine elicited neutralizing antibodies, and following challenge with influenza A/California/07/2009 virus reduced morbidity and lowered viral titers in nasal lavages.
Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Vírus da Influenza A Subtipo H1N1/imunologia , Vacinas contra Influenza/imunologia , Células Th1/imunologia , Vacinas de Partículas Semelhantes a Vírus/imunologia , Adjuvantes Imunológicos , Compostos de Alúmen , Animais , Especificidade de Anticorpos , Bacteriófagos/imunologia , Escherichia coli/genética , Escherichia coli/imunologia , Feminino , Furões/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Humanos , Imunoglobulina G/imunologia , Interferon gama/biossíntese , Camundongos , Infecções por Orthomyxoviridae/prevenção & controle , RNA Bacteriano/imunologia , Especificidade do Receptor de Antígeno de Linfócitos T/imunologia , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Células Th1/metabolismoRESUMO
Pre-existing immunity against vaccine carrier proteins has been reported to inhibit the immune response against antigens conjugated to the same carrier by a process termed carrier induced epitopic suppression (CIES). Hence understanding the phenomenon of CIES is of major importance for the development of conjugate vaccines. Virus-like particles (VLPs) are a novel class of potent immunological carriers which have been successfully used to enhance the antibody response to virtually any conjugated antigen. In the present study we investigated the impact of a pre-existing VLP-specific immune response on the development of antibody responses against a conjugated model peptide after primary, secondary and tertiary immunization. Although VLP-specific immune responses led to reduced peptide-specific antibody titers, we showed that CIES against peptide-VLP conjugates could be overcome by high coupling densities, repeated injections and/or higher doses of conjugate vaccine. Furthermore we dissected VLP-specific immunity by adoptively transferring VLP-specific antibodies, B-cells or T(helper) cells separately into naïve mice and found that the observed CIES against peptide-VLP conjugates was mainly mediated by carrier-specific antibodies.
Assuntos
Allolevivirus/imunologia , Anticorpos Antivirais/imunologia , Antígenos/imunologia , Proteínas do Capsídeo/imunologia , Capsídeo/imunologia , Epitopos/imunologia , Tolerância Imunológica , Peptídeos/imunologia , Allolevivirus/genética , Animais , Formação de Anticorpos , Linfócitos B/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Linfócitos T Auxiliares-Indutores/imunologia , VirossomosRESUMO
Intranasal (i.n.) immunization aims to induce local as well as systemic immune responses. In the present study, we assessed a vaccine platform based on virus-like particles (VLP) derived from the RNA phage Qbeta for i.n. immunization. We found that both i.n. and subcutaneous (s.c.) administration of Qbeta-VLP elicited strong and comparable specific IgG responses in serum and lung. Surprisingly, both routes also induced high levels of specific IgA in serum. In contrast, only i.n. administration of Qbeta-VLP resulted in local IgA production in the lung. Efficient induction of B cell responses by i.n. administration of VLP was further supported by the presence of large numbers of germinal centers (GC) as well as memory B cells in the spleen and plasma cells in the bone marrow. Results obtained for the VLP itself could be extended to an antigen covalently attached to it. Specifically, i.n. immunization of mice with VLP displaying the influenza virus derived ectodomain of the M2 protein resulted in strong M2-specific antibody responses as well as anti-viral protection. In contrast, i.n. immunization with VLP displaying p33 peptide, the major CTL epitope of lymphocytic choriomeningitis virus, induced relatively inefficient cytotoxic T cell responses, resulting in low numbers of specific T cells and poor effector cell differentiation. Taken together, these results suggest that effective antibody-based vaccines are achievable by i.n. administration of Qbeta-VLP displaying specific antigens.
Assuntos
Administração Intranasal , Imunidade nas Mucosas , RNA Viral/administração & dosagem , Vacinação/métodos , Vacinas Virais/administração & dosagem , Vírion/imunologia , Animais , Anticorpos Antivirais/sangue , Formação de Anticorpos , Linfócitos B/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Imunofluorescência , Centro Germinativo/imunologia , Imunoglobulina A/sangue , Imunoglobulina A/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , RNA Viral/imunologia , Baço/imunologia , Linfócitos T Citotóxicos/imunologia , Proteínas da Matriz Viral/imunologia , Vacinas Virais/imunologiaRESUMO
Although IgG2a is the most potent Ab isotype in the host response to viral and bacterial infections, the regulation of class switch recombination to IgG2a in vivo is not yet well understood. Recognition of pathogen-associated molecular patterns by dendritic cells expressing TLRs, like TLR7, recognizing ssRNA, or TLR9, recognizing DNA rich in nonmethylated CG motifs (CpG), favors induction of Th1 responses. It is generally assumed that these Th1 responses are responsible for the TLR-mediated induction of IgG2a. Using virus-like particles loaded with CpGs, we show here that TLR9 ligands can directly stimulate B cells to undergo isotype switching to IgG2a. Unexpectedly, TLR9 expression in non-B cells did not affect isotype switching in the Ab response against virus-like particles. Thus, TLR9 can regulate isotype switching to IgG2a directly by interacting with B cells rather than indirectly by inducing Th1 responses.
Assuntos
Linfócitos B/imunologia , Switching de Imunoglobulina/imunologia , Imunoglobulina G/imunologia , Receptor Toll-Like 9/imunologia , Animais , Linfócitos B/citologia , Infecções Bacterianas/imunologia , Ilhas de CpG/imunologia , Ligantes , Glicoproteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos BALB C , RNA/imunologia , Células Th1/citologia , Células Th1/imunologia , Receptor 7 Toll-Like/imunologia , Viroses/imunologiaRESUMO
Virus-like particles (VLPs) are able to induce cytotoxic T-cell responses in the absence of infection or replication. This makes VLPs promising candidates for the development of recombinant vaccines. However, VLPs are also potent inducers of B-cell responses, and it is generally assumed that such VLP-specific antibodies interfere with the induction of protective immune responses, a phenomenon summarized as carrier suppression. In this study, we investigated the impact of preexisting VLP-specific antibodies on the induction of specific cytotoxic T-cell and Th-cell responses in mice. The data show that VLP-specific antibodies did not measurably reduce antigen presentation in vitro or in vivo. Nevertheless, T-cell priming was slightly reduced by antigen-specific antibodies; however, the overall reduction was limited and vaccination with VLPs in the presence of VLP-specific antibodies still resulted in protective T-cell responses. Thus, carrier suppression is unlikely to be a limiting factor for VLP-based T-cell vaccines.
Assuntos
Anticorpos Antivirais/imunologia , Epitopos de Linfócito T , Linfócitos T/imunologia , Vírion/imunologia , Sequência de Aminoácidos , Animais , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Receptores de Antígenos de Linfócitos T/fisiologia , VacinaçãoRESUMO
Vaccination of mice with a peptide corresponding to the extracellular part of M2 protein coupled to the immunodominant domain of hepatitis B core can protect mice from a lethal challenge with influenza A virus. As the extracellular part of M2 protein is highly conserved in all known human influenza A strains, such a vaccine may protect against all human influenza A strains, which would represent a major advantage over current vaccine strategies. The present study demonstrates that protection is mediated exclusively by Abs, a very important feature of a successful preventive vaccine. However, these Abs neither bind efficiently to the free virus nor neutralize virus infection, but bind to M2 protein expressed on the surface of virus-infected cells. The presence of NK cells is important for protection, whereas complement is not, supposing that protection is mediated via Ab-dependent, cell-mediated cytotoxicity. The absence of neutralizing Abs results in much weaker protection than that achieved by vaccination with UV-inactivated influenza virus. Specifically, whereas neutralizing Abs completely eliminate signs of disease even at high viral challenge doses, M2-specific Abs cannot prevent infection, but merely reduce disease at low challenge doses. M2-specific Abs fail to protect from high challenge doses, as vaccinated mice undergo lethal infection under these conditions. In conclusion, protection mediated by M2-hepatitis B core vaccine would be insufficient during the yearly epidemics, for which full protection is desirable, and overall is clearly inferior to protection achieved by immunization with classical inactivated viral preparations.
Assuntos
Anticorpos Antivirais/fisiologia , Citotoxicidade Celular Dependente de Anticorpos/imunologia , Vírus da Influenza A/imunologia , Vacinas contra Influenza/imunologia , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Infecções por Orthomyxoviridae/prevenção & controle , Proteínas da Matriz Viral/imunologia , Animais , Anticorpos Antivirais/biossíntese , Anticorpos Antivirais/metabolismo , Especificidade de Anticorpos , Sítios de Ligação de Anticorpos , Líquido da Lavagem Broncoalveolar/citologia , Complemento C3/deficiência , Complemento C3/genética , Líquido Extracelular/imunologia , Líquido Extracelular/virologia , Feminino , Vírus da Hepatite B/imunologia , Imunoglobulina G/biossíntese , Imunoglobulina G/classificação , Vírus da Influenza A/efeitos da radiação , Vacinas contra Influenza/administração & dosagem , Células Matadoras Naturais/virologia , Depleção Linfocítica , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Infecções por Orthomyxoviridae/imunologia , Estrutura Terciária de Proteína , Linfócitos T/imunologia , Vacinas Combinadas/administração & dosagem , Vacinas Combinadas/imunologia , Proteínas da Matriz Viral/administração & dosagem , Proteínas da Matriz Viral/metabolismo , Inativação de Vírus/efeitos da radiaçãoRESUMO
Epitope density and organization have been shown to be important factors for B cell activation in many animal model systems. However, it has been difficult to separate the role of antigen organization from the role of local antigen concentrations because highly organized antigens are usually particulate whereas non-organized antigens are more soluble. Hence, highly organized and non-organized antigens may interact with different cell types and in different locations within lymphoid organs. In order to assess the role of antigen organization in regulating B cell responses, we immunized mice with highly repetitive virus-like particles, which exhibit different epitope densities covalently attached to them. Therefore, the same particulate structure was used to present identical epitopes that differed in their degree of organization. Induction of epitope-specific IgM titers, reflecting early B cell activation, were unaffected by the degree of epitope density. Furthermore, the absence of Th cells or CD21/CD35 did not reduce the IgM response. In contrast, the degree of organization was a critical factor influencing the magnitude of the epitope-specific IgG response. Moreover, the threshold for IgG responses was shifted in the absence of CD21/CD35, resulting in the requirement for higher epitope densities to allow efficient IgG responses. Thus, IgG but not IgM responses are regulated by epitope density and B cell costimulatory thresholds.
Assuntos
Linfócitos B/imunologia , Epitopos , Imunoglobulina G/biossíntese , Receptores de Complemento 3d/fisiologia , Sequência de Aminoácidos , Animais , Antígenos CD/fisiologia , Feminino , Imunoglobulina M/biossíntese , Proteínas de Membrana/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Receptores de Complemento 3b/fisiologia , Linfócitos T Auxiliares-Indutores/imunologia , Tetraspanina 28 , Vírion/imunologiaRESUMO
Virus-like particles (VLPs) are known to induce strong Ab responses in the absence of adjuvants. In addition, VLPs are able to prime CTL responses in vivo. To study the efficiency of this latter process, we fused peptide p33 derived from lymphocytic choriomeningitis virus to the hepatitis B core Ag, which spontaneously assembles into VLPs (p33-VLPs). These p33-VLPs were efficiently processed in vitro and in vivo for MHC class I presentation. Nevertheless, p33-VLPs induced weak CTL responses that failed to mediate effective protection from viral challenge. However, if APCs were activated concomitantly in vivo using either anti-CD40 Abs or CpG oligonucleotides, the CTL responses induced were fully protective against infection with lymphocytic choriomeningitis virus or recombinant vaccinia virus. Moreover, these CTL responses were comparable to responses generally induced by live vaccines, because they could be measured in primary ex vivo (51)Cr release assays. Thus, while VLPs alone are inefficient at inducing CTL responses, they become very powerful vaccines if applied together with substances that activate APCs.
Assuntos
Células Apresentadoras de Antígenos/imunologia , Citotoxicidade Imunológica , Ativação Linfocitária/imunologia , Vírus da Coriomeningite Linfocítica/imunologia , Linfócitos T Citotóxicos/imunologia , Vacinas Virais/imunologia , Vírion/imunologia , Adjuvantes Imunológicos/administração & dosagem , Animais , Anticorpos Monoclonais/administração & dosagem , Apresentação de Antígeno/genética , Antígenos Virais/administração & dosagem , Antígenos Virais/genética , Antígenos Virais/imunologia , Antígenos CD40/imunologia , Radioisótopos de Cromo , Testes Imunológicos de Citotoxicidade , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/imunologia , Epitopos de Linfócito T/metabolismo , Glicoproteínas/administração & dosagem , Glicoproteínas/genética , Glicoproteínas/imunologia , Antígenos do Núcleo do Vírus da Hepatite B/genética , Antígenos do Núcleo do Vírus da Hepatite B/imunologia , Injeções Intradérmicas , Injeções Subcutâneas , Células L , Coriomeningite Linfocítica/prevenção & controle , Vírus da Coriomeningite Linfocítica/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Oligodesoxirribonucleotídeos/administração & dosagem , Oligodesoxirribonucleotídeos/imunologia , Fragmentos de Peptídeos/administração & dosagem , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/imunologia , Proteínas Recombinantes de Fusão/imunologia , Proteínas Recombinantes de Fusão/metabolismo , Linfócitos T Citotóxicos/virologia , Células Tumorais Cultivadas , Vacínia/prevenção & controle , Proteínas Virais/administração & dosagem , Proteínas Virais/genética , Proteínas Virais/imunologia , Vacinas Virais/administração & dosagem , Vacinas Virais/genética , Vírion/genéticaRESUMO
Induction of protective immune responses with recombinant antigens is a major challenge for the vaccine industry. Here we present a molecular assembly system that renders antigens of choice highly repetitive. Using this method, efficient antibody responses may be induced in the absence of adjuvants resulting in protection from viral infection and allergic reactions.
Assuntos
Vacinas Virais/administração & dosagem , Vírion/imunologia , Animais , Antígenos/imunologia , Humanos , Hipersensibilidade/terapia , Imunoterapia , Vacinas Virais/uso terapêuticoRESUMO
Virus like particles (VLPs) are known to induce potent B cell responses in the absence of adjuvants. Moreover, epitope-specific antibody responses may be induced by VLPs that contain peptides inserted in their immunodominant regions. However, due to steric problems, the size of the peptides capable of being incorporated into VLPs while still permitting capsid assembly, is rather limited. While peptides genetically fused to either the N- or C-terminus of VLPs present fewer assembly problems, the immune responses obtained against such epitopes are often limited, most likely because the epitopes are not optimally exposed. In addition, such particles may be less stable in vivo. Here, we show that peptides and proteins engineered to contain a free cys can be chemically coupled to VLPs formed from the hepatitis B core antigen (HBcAg) containing a lys in the immuno-dominant region. By using this approach steric hindrance of capsid assembly is abrogated. Peptides or protein coupled to VLPs in an oriented fashion are shown to induce strong and protective B cell responses even against self-epitopes in the absence of adjuvants. This molecular assembly system may be used to induce strong B cell responses against most antigens.