RESUMO
Endemic human coronaviruses (hCoVs) are common causative agents of respiratory tract infections, affecting especially children. However, in the ongoing SARS-CoV-2 pandemic, children are the least affected age-group. The objective of this study was to investigate the magnitude of endemic hCoVs antibodies in Finnish children and adults, and pre-pandemic antibody cross-reactivity with SARS-CoV-2. Antibody levels against endemic hCoVs start to rise at a very early age, reaching to overall 100% seroprevalence. No difference in the antibody levels was detected for OC43 but the magnitude of 229E-specific antibodies was significantly higher in the sera of children. OC43 and 229E hCoV antibody levels of children correlated significantly with each other and with the level of cross-reactive SARS-CoV-2 antibodies, whereas these correlations completely lacked in adults. Although none of the sera showed SARS-CoV-2 neutralization, the higher overall hCoV cross-reactivity observed in children might, at least partially, contribute in controlling SARS-CoV-2 infection in this population.
Assuntos
Anticorpos Antivirais/sangue , COVID-19/epidemiologia , Coronavirus Humano 229E/imunologia , Coronavirus Humano OC43/imunologia , SARS-CoV-2/imunologia , Adulto , Especificidade de Anticorpos , COVID-19/imunologia , COVID-19/virologia , Criança , Pré-Escolar , Reações Cruzadas , Doenças Endêmicas , Ensaio de Imunoadsorção Enzimática , Finlândia/epidemiologia , Humanos , Lactente , Pessoa de Meia-Idade , Estudos SoroepidemiológicosRESUMO
Recombinant protein technology enables the engineering of modern vaccines composed of a carrier protein displaying poorly immunogenic heterologous antigens. One promising carrier is based on the rotavirus inner-capsid VP6 protein. We explored different VP6 insertion sites for the presentation of two peptides (23 and 140 amino acids) derived from the M2 and HA genes of influenza A virus. Both termini and three surface loops of VP6 were successfully exploited as genetic fusion sites, as demonstrated by the expression of the fusion proteins. However, further studies are needed to assess the morphology and immunogenicity of these constructs.
Assuntos
Antígenos Virais/genética , Proteínas do Capsídeo/genética , Vírus da Influenza A/genética , Peptídeos/genética , Rotavirus/genética , Anticorpos Antivirais/genética , Formação de Anticorpos/genética , Capsídeo/metabolismo , Proteínas Recombinantes/genéticaRESUMO
AIM: Our aim was to compare the presence of various common viruses (rhinovirus, enterovirus, adenovirus, Epstein-Barr virus, cytomegalovirus, norovirus, parechovirus) in stool and nasal swab samples as well as virus-specific antibodies in serum samples between children who developed coeliac disease and controls. METHODS: A case-control study was established based on the DIABIMMUNE Study cohorts. During the study, eight Estonian children and 21 Finnish children aged 1.5 years to five years developed coeliac disease and each was matched with a disease-free control. Nasal swabs and stool samples were taken at the age of three to six months and the serum samples at the time of diagnosis. RESULTS: Rhinovirus ribonucleic acid was detected in the nasal swabs from five coeliac disease children, but none of the control children (p = 0.05). There were no statistically significant differences in the level of viral antibodies between cases and controls. Enterovirus immunoglobulin G class antibodies were found more frequently in the Estonian than in the Finnish children (63% versus 23%, p = 0.02). CONCLUSION: This study did not find any marked overall differences in laboratory-confirmed common viral infections between the children who developed coeliac disease and the controls. However, rhinovirus infections were detected slightly more often in those patients who developed coeliac disease.
Assuntos
Doença Celíaca/virologia , Viroses/complicações , Anticorpos Antivirais/sangue , Estudos de Casos e Controles , Doença Celíaca/imunologia , Pré-Escolar , Estudos de Coortes , Fezes/virologia , Humanos , Nariz/virologiaRESUMO
The best acknowledged correlate of protection from norovirus (NoV) infection is the ability of serum antibodies to block binding of NoV virus-like particles (VLPs) to histo-blood group antigens (HBGAs). We investigated mucosal NoV-specific antibody levels in adult volunteers and used saliva from a single donor to determine whether purified saliva antibodies confer blocking. NoV-specific IgG and IgA levels in saliva and plasma samples were measured against four NoV genotype VLPs. NoV-specific IgG and IgA titers in saliva and plasma samples correlated significantly. Antibodies were detected against all VLPs with the highest level of antibodies directed against ancestral GII.4 99 genotype. Affinity chromatography purified salivary IgA and IgG blocked binding of GII.4 99 VLPs to HBGAs. Saliva sampling is a non-invasive alternative to blood drawing and an excellent biological fluid to study NoV-specific immune responses. Mucosal anti-NoV antibodies block binding of NoV VLPs to HBGAs, and may therefore be protective.
Assuntos
Anticorpos Bloqueadores/imunologia , Anticorpos Antivirais/imunologia , Antígenos de Grupos Sanguíneos/imunologia , Imunidade nas Mucosas/imunologia , Imunoglobulina A Secretora/imunologia , Imunoglobulina G/imunologia , Norovirus/imunologia , Saliva/imunologia , Adulto , Infecções por Caliciviridae/imunologia , Cromatografia de Afinidade , Ensaio de Imunoadsorção Enzimática , Feminino , Genótipo , Voluntários Saudáveis , Humanos , Imunoglobulina A/imunologia , Masculino , Pessoa de Meia-Idade , Norovirus/genéticaRESUMO
Norovirus (NoV) -derived virus-like particles (VLPs) resemble empty shells of the virus and NoV P-particles contain only protruding domains of the NoV capsid. Both NoV-derived subviral particles show similar functionality and antigenicity in vitro and are considered to be potential vaccine candidates against NoV gastroenteritis. BALB/c mice were immunized with baculovirus-produced GII-4 VLPs or the corresponding Escherichia coli-produced P-particles by the intramuscular or intradermal route and the NoV-specific antibody and T-cell immune responses were compared. Elevated antibody levels were induced with a single VLP immunization, whereas P-particle immunization required a boost. High avidity antibodies were raised only by VLP immunization. VLP immunization resulted in a balanced T helper type 1/type 2 immune response whereas P-particles induced a T helper type 2-biased response. Only VLP immunization primed T cells for interferon-γ production. Most importantly, cross-reactive B and T cells were induced solely by VLP immunization. In addition, VLP antiserum blocked the binding of heterotypic VLPs to human histo-blood group antigen receptor and saliva. The findings in this study are relevant for the development of NoV vaccines.
Assuntos
Infecções por Caliciviridae/imunologia , Gastroenterite/imunologia , Norovirus/imunologia , Vacinas de Partículas Semelhantes a Vírus/imunologia , Animais , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Antígenos de Grupos Sanguíneos/imunologia , Feminino , Gastroenterite/virologia , Humanos , Interferon gama/biossíntese , Interferon gama/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Saliva/imunologia , Linfócitos T/imunologiaRESUMO
Virus-like particles (VLPs) modified through different molecular technologies are employed as delivery vehicles or platforms for heterologous antigen display. We have recently created a norovirus (NoV) VLP platform, where two influenza antigens, the extracellular domain of matrix protein M2 (M2e) or the stem domain of the major envelope glycoprotein hemagglutinin (HA2) are displayed on the surface of the NoV VLPs by SpyTag/SpyCatcher conjugation. To demonstrate the feasibility of the platform to deliver foreign antigens, this study examined potential interference of the conjugation with induction of antibodies against conjugated M2e peptide, HA2, and NoV VLP carrier. High antibody response was induced by HA2 but not M2e decorated VLPs. Furthermore, HA2-elicited antibodies did not neutralize the homologous influenza virus in vitro. Conjugated NoV VLPs retained intact receptor binding capacity and self-immunogenicity. The results demonstrate that NoV VLPs could be simultaneously used as a platform to deliver foreign antigens and a NoV vaccine.
Assuntos
Anticorpos Antivirais/biossíntese , Hemaglutininas Virais/genética , Imunoglobulina G/biossíntese , Vacinas contra Influenza/genética , Influenza Humana/prevenção & controle , Infecções por Orthomyxoviridae/prevenção & controle , Vacinas de Partículas Semelhantes a Vírus/genética , Animais , Antígenos Virais/genética , Antígenos Virais/imunologia , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/imunologia , Feminino , Hemaglutininas Virais/imunologia , Humanos , Imunoconjugados/genética , Imunoconjugados/imunologia , Imunogenicidade da Vacina , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H1N1/patogenicidade , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/biossíntese , Influenza Humana/imunologia , Influenza Humana/virologia , Camundongos , Camundongos Endogâmicos BALB C , Norovirus/genética , Norovirus/imunologia , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/virologia , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Vacinação/métodos , Vacinas de Partículas Semelhantes a Vírus/administração & dosagem , Vacinas de Partículas Semelhantes a Vírus/biossíntese , Proteínas da Matriz Viral/genética , Proteínas da Matriz Viral/imunologiaRESUMO
Noroviruses (NoV) are the leading cause of epidemic acute gastroenteritis in humans worldwide. A safe and effective vaccine that prevents NoV infection or minimizes NoV disease burden is needed, especially for children and the elderly who are particularly susceptible to NoV disease. A plant-based expression system (magnICON®) was used to manufacture two different virus-like particle (VLP) immunogens derived from human NoV genogroups I and II, genotype 4 (GI.4 and GII.4), which were subsequently blended 1:1 (w/w) into a bivalent vaccine composition (rNV-2v). Here, we report on the safety and immunogenicity of rNV-2v from one pilot and two GLP-compliant toxicity studies in New Zealand White rabbits administered the vaccine subcutaneously (SC) or intramuscularly (IM). Strong genogroup-specific immune responses were induced by vaccination without adjuvant at various doses (200 to 400 µg VLP/administration) and administration schedules (Days 1 and 7; or Days 1, 15 and 29). The results showed sporadic local irritation at the injection site, which resolved over time, and was non-adverse and consistent with expected reactogenicity. There were no signs of systemic toxicity related to vaccine administration relative to vehicle-treated controls with respect to clinical chemistry, haematology, organ weights, macroscopic examinations, or histopathology. In a 3-administration regimen (n + 1 the clinical regimen), the NOAEL for rNV-2v via the SC or IM route was initially determined to be 200 µg. An improved GI.4 VLP variant mixed 1:1 (w/w) with the wild-type GII.4 VLP was subsequently evaluated via the IM route at a higher dose in the same 3-administration model, and the NOAEL was raised to 300 µg. Serology performed in samples of both toxicity studies showed significant and substantial anti-VLP-specific antibody titers for rNV-2v vaccines administered via the IM or SC route, as well as relevant NoV blocking antibody responses. These results support initiation of clinical development of the plant-made NoV vaccine.
Assuntos
Infecções por Caliciviridae , Norovirus , Vacinas de Partículas Semelhantes a Vírus , Vacinas Virais , Animais , Anticorpos Antivirais , Modelos Animais , CoelhosRESUMO
Noroviruses (NoV) are the leading cause of epidemic acute gastroenteritis in humans worldwide and a safe and effective vaccine is needed. Here, a phase I, double-blind, placebo-controlled clinical trial was performed in 60 healthy adults, 18 to 40 years old. Safety (primary objective) and immunogenicity (secondary and exploratory objectives) of a bivalent (GI.4 and GII.4), plant-produced, virus-like particle (VLP), NoV vaccine candidate formulation were investigated at two dose levels (50 µg + 50 µg and 150 µg + 150 µg) without adjuvant. Overall, 13 subjects (65.0%) in the 50 µg group, 16 subjects (80.0%) in the 150 µg group, and 14 subjects (70.0%) in the placebo group reported at least 1 solicited local or general symptom during the 7-day post-vaccination periods following each dose. Severe solicited adverse events (AEs) were rare (2 events in the 50 µg group). A total of 8 subjects (40.0%) in each group reported at least one unsolicited AE during the 28-day post-vaccination periods. Immunogenicity was assessed on days 1, 8, 29, 57, 183 and 365. All subjects were pre-exposed to norovirus as indicated by baseline levels of the different immunological parameters examined. Vaccine-specific humoral and cellular immune responses increased after the first dose but did not rise further after the second vaccination. Increased GI.4- and GII.4-specific IgG titers persisted until day 365. The vaccine elicited cross-reactive IgG antibodies against non-vaccine NoV VLPs, which was more pronounced for NoV strains of the same genotype as the GII.4 vaccine strain than for non-vaccine genotypes. Significant blocking anti-GI.4 and anti-GII.4 VLP titers were triggered in both dose groups. Lymphoproliferation assays revealed strong cell-mediated immune responses that persisted until day 365. In conclusion, both dose levels were safe and well-tolerated, and no higher incidence of AEs was observed in the higher dose group. The data show that a single dose of the vaccine formulated at 50 µg of each VLP is sufficient to reach a peak immune response after 8 to 28 days. The results of this Phase I study warrant further evaluation of the non-adjuvanted vaccine candidate. Clinical trial registration: https://clinicaltrials.gov/ct2/show/record/NCT05508178, identifier (NCT05508178).
Assuntos
Infecções por Caliciviridae , Gastroenterite , Norovirus , Vacinas Virais , Adulto , Humanos , Adolescente , Adulto Jovem , Imunoglobulina G , Adjuvantes ImunológicosRESUMO
Vaccines based on mRNA and viral vectors are currently used in the frontline to combat the ongoing pandemic caused by the novel Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). However, there is still an urgent need for alternative vaccine technologies inducing/boosting long-lasting and cross-reactive immunity in different populations. As a possible vaccine candidate, we employed the rotavirus VP6-protein platform to construct a fusion protein (FP) displaying receptor-binding domain (RBD) of SARS-CoV-2 spike protein (S) at the N-terminus of VP6. The recombinant baculovirus-insect cell produced VP6-RBD FP was proven antigenic in vitro and bound to the human angiotensin-converting enzyme 2 (hACE2) receptor. The FP was used to immunize BALB/c mice, and humoral- and T cell-mediated immune responses were investigated. SARS-CoV-2 RBD-specific T cells were induced at a high quantity; however, no RBD or S-specific antibodies were detected. The results suggest that conformational B cell epitopes might be buried inside the VP6, while RBD-specific T cell epitopes are available for T cell recognition after the processing and presentation of FP by the antigen-presenting cells. Further immunogenicity studies are needed to confirm these findings and to assess whether, under different experimental conditions, the VP6 platform may present SARS-CoV-2 antigens to B cells as well.
RESUMO
We have previously shown that rotavirus (RV) inner capsid protein VP6 has an adjuvant effect on norovirus (NoV) virus-like particle- (VLP-) induced immune responses and studied the adjuvant mechanism in immortalized cell lines used as antigen-presenting cells (APCs). Here, we investigated the uptake and presentation of RV VP6 and NoV GII.4 VLPs by primary bone marrow-derived dendritic cells (BMDCs). The adjuvant effect of VP6 on GII.4 VLP presentation and NoV-specific immune response induction by BMDC in vivo was also studied. Intracellular staining demonstrated that BMDCs internalized both antigens, but VP6 more efficiently than NoV VLPs. Both antigens were processed and presented to antigen-primed T cells, which responded by robust interferon γ secretion. When GII.4 VLPs and VP6 were mixed in the same pulsing reaction, a subpopulation of the cells had uptaken both antigens. Furthermore, VP6 copulsing increased GII.4 VLP uptake by 37% and activated BMDCs to secrete 2-5-fold increased levels of interleukin 6 and tumor necrosis factor α compared to VLP pulsing alone. When in vitro-pulsed BMDCs were transferred to syngeneic BALB/c mice, VP6 improved NoV-specific antibody responses. The results of this study support the earlier findings of VP6 adjuvant effect in vitro and in vivo.
Assuntos
Adjuvantes Imunológicos/administração & dosagem , Antígenos Virais/administração & dosagem , Infecções por Caliciviridae/prevenção & controle , Proteínas do Capsídeo/administração & dosagem , Células Dendríticas/imunologia , Norovirus/imunologia , Vacinas Virais/administração & dosagem , Animais , Antígenos Virais/imunologia , Infecções por Caliciviridae/imunologia , Infecções por Caliciviridae/virologia , Proteínas do Capsídeo/imunologia , Células Cultivadas , Reações Cruzadas , Células Dendríticas/metabolismo , Modelos Animais de Doenças , Feminino , Humanos , Imunogenicidade da Vacina , Interleucina-6/metabolismo , Camundongos , Cultura Primária de Células , Fator de Necrose Tumoral alfa/metabolismo , Vacinas Virais/imunologiaRESUMO
Nanoparticles are highly immunogenic due to the multivalent, repetitive antigen expression and direct activation of antigen presenting cells (APCs), key players of adaptive immune responses. Different virus-like particles (VLPs) have been used as display platforms to amplify immune responses to biologically relevant, but poorly immunogenic foreign antigens. A candidate platform based on rotavirus (RV) inner-capsid protein VP6 oligomers, such as nanotubes (T-VP6) and nanospheres (S-VP6), is also considered. Different VP6 nanostructures were compared for internalization and antigen presentation by the APCs. We found, that a lack of a high-order structures, T-VP6 and S-VP6, did not negatively affect VP6 uptake and presentation by murine bone-marrow derived dendritic cells (BMDCs) in vitro. Furthermore, T-VP6 was preferable to norovirus (NoV) VLPs for BMDC internalization resulting in significantly higher VP6-specific immune responses when T-VP6 and NoV VLP pulsed BMDCs were transferred to syngeneic mice. These results support the use of different VP6 nanostructures as foreign antigen delivery platforms.
Assuntos
Apresentação de Antígeno , Antígenos Virais/imunologia , Antígenos Virais/metabolismo , Proteínas do Capsídeo/imunologia , Proteínas do Capsídeo/metabolismo , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Rotavirus/fisiologia , Animais , Formação de Anticorpos , Antígenos Virais/química , Proteínas do Capsídeo/química , Células Cultivadas , Células Dendríticas/virologia , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Nanoestruturas/química , Estrutura Terciária de Proteína/fisiologia , Transporte Proteico , Proteínas Recombinantes/química , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/metabolismo , Rotavirus/metabolismo , Internalização do VírusRESUMO
Novel adjuvants present a concern for adverse effects, generating a need for alternatives. Rotavirus inner capsid VP6 protein could be considered a potential candidate, due to its ability to self-assemble into highly immunogenic nanospheres and nanotubes. These nanostructures exhibit immunostimulatory properties, which resemble those of traditional adjuvants, promoting the uptake and immunogenicity of the co-administered antigens. We have previously elucidated an adjuvant effect of VP6 on co-delivered norovirus and coxsackievirus B1 virus-like particles, increasing humoral and cellular responses and sparing the dose of co-delivered antigens. This study explored an immunostimulatory effect of VP6 nanospheres on smaller antigens, P particles formed by protruding domain of a norovirus capsid protein and a short peptide, extracellular matrix protein (M2e) of influenza A virus. VP6 exhibited a notable improving impact on immune responses induced by P particles in immunized mice, including systemic and mucosal antibody and T cell responses. The adjuvant effect of VP6 nanospheres was comparable to the effect of alum, except for induction of superior mucosal and T cell responses when P particles were co-administered with VP6. However, unlike alum, VP6 did not influence M2e-specific immune responses, suggesting that the adjuvant effect of VP6 is dependent on the particulate nature of the co-administered antigen.
RESUMO
Norovirus (NoV) genotype GII.4 is responsible for the majority of NoV infections causing pandemics every few years. A NoV virus-like particle (VLP)-based vaccine should optimally cover the high antigenic variation within the GII.4 genotype. We compared the immune responses generated by VLPs of the ancestral GII.4 1999 strain (GII.4 1995/96 US variant) and the most recent GII.4 Sydney 2012 pandemic strains in mice. No significant differences were observed in the type-specific responses but GII.4 1999 VLPs were more potent in inducing high-avidity antibodies with better cross-reactivity. GII.4 1999 immune sera blocked binding of GII.4 2006 and GII.4 2012 VLPs to the putative receptors in a surrogate neutralization assay, whereas GII.4 2012 immune sera only had low blocking activity against GII.4 2006 VLPs. Amino acid substitution in the NERK motif (amino acids 310, 316, 484, and 493, respectively), altering the access to conserved blocking epitope F, moderately improved the cross-blocking responses against mutated GII.4 2012 VLPs (D310N). NoV GII.4 1999 VLPs, uptaken and processed by antigen-presenting cells, induced stronger interferon gamma (IFN-γ) production from mice splenocytes than GII.4 2012 VLPs. These results support the use of GII.4 1999 VLPs as a major component of a NoV vaccine.
Assuntos
Anticorpos Antivirais/sangue , Infecções por Caliciviridae/prevenção & controle , Reações Cruzadas , Norovirus/imunologia , Vacinas de Partículas Semelhantes a Vírus/imunologia , Animais , Anticorpos Bloqueadores/sangue , Afinidade de Anticorpos , Infecções por Caliciviridae/imunologia , Epitopos/imunologia , Feminino , Gastroenterite/prevenção & controle , Genótipo , Humanos , Interferon gama/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Norovirus/genética , Pandemias , Baço/citologia , Baço/imunologiaRESUMO
Rotaviruses (RVs) and noroviruses (NoVs) are major causes of childhood acute gastroenteritis. During development of a combination vaccine based on NoV virus-like particles (VLP) and RV VP6 produced in baculovirus expression system in insect cells, a dual role of VP6 as a vaccine antigen and an adjuvant for NoV-specific immune responses was discovered. Here the VP6 adjuvant effect on bivalent GI.4 and GII.4-2006a NoV VLPs produced in Nicotiana benthamiana was investigated. BALB/c mice were immunized intradermally with suboptimal (0.3 µg) dose of each NoV VLP alone or combined with 10 µg of VP6, or equal doses of NoV VLPs and VP6 (1 µg/antigen). NoV-specific serum IgG antibodies and their blocking activity were analyzed using vaccine-homologous and heterologous NoV VLPs. Immunization with 0.3 µg NoV VLPs alone was insufficient to induce NoV-specific immune responses, but with co-administration of 10 µg of VP6, antibodies against vaccine-derived and heterologous NoV genotypes were generated. Furthermore, corresponding adjuvant effect of VP6 was observed with 1 µg dose. Efficient uptake and presentation of VP6 by dendritic cells was demonstrated in vitro. These results show that adjuvant effect of VP6 on bivalent NoV VLP vaccine is independent of the cell source used for vaccine production.
RESUMO
Majority of norovirus (NoV) outbreaks and sporadic infections in the past 20 years have been caused by GII.4 variants. In 2014, NoV GII.17 genotype replaced GII.4 strains in several Asian countries and major outbreaks were reported in other continents. As GII.17 is a recently evolved NoV strain, there is a gap especially in immunogenicity data. In this study, we investigated GII.17 virus-like particle (VLP) binding to various cellular ligands, histo-blood group antigens (HBGAs), using human saliva, pig gastric mucin, and synthetic oligosaccharides as HBGA sources. The level of GII.17 immunological cross-reactivity was determined in mice immunized with different monovalent and multivalent NoV VLP compositions. Furthermore, healthy adult volunteers with natural NoV exposure history were analyzed for GII.17-specific seroresponses. The results showed that GII.17 Kawasaki VLPs bind to a wide range of HBGAs, even though fewer than GII.4 VLPs. Immunization of mice with a multivalent VLP formulation containing different genogroup II NoV VLPs was required to obtain the highest magnitude of cross-reactive binding antibodies to GII.17. However, coimmunization with different VLP genotypes did not improve potentially neutralizing antibodies to GII.17, which remained very moderate. Low pre-existing cross-reactive antibodies to GII.17 observed in human adults indicate the presence of a large pool of susceptible individuals in this population. These data suggest that GII.17 and alike newly emerging distinct NoV genotypes should be considered as an antigenic component for vaccine formulations, which currently widely rely on GII.4-specific immunity.
Assuntos
Antígenos de Grupos Sanguíneos/imunologia , Infecções por Caliciviridae/prevenção & controle , Surtos de Doenças/prevenção & controle , Norovirus/imunologia , Vacinas Virais/imunologia , Adulto , Sequência de Aminoácidos/genética , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/metabolismo , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/metabolismo , Antígenos de Grupos Sanguíneos/metabolismo , Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/imunologia , Infecções por Caliciviridae/virologia , Proteínas do Capsídeo/imunologia , Reações Cruzadas , Epitopos/genética , Epitopos/imunologia , Feminino , Voluntários Saudáveis , Humanos , Imunogenicidade da Vacina , Camundongos , Pessoa de Meia-Idade , Norovirus/genética , Suínos , Vacinas de Partículas Semelhantes a Vírus/administração & dosagem , Vacinas de Partículas Semelhantes a Vírus/imunologia , Vacinas Virais/administração & dosagemRESUMO
Norovirus (NoV) is the main cause of acute gastroenteritis worldwide across all age groups. Current NoV vaccine candidates are based on non-infectious highly immunogenic virus-like particles (VLPs) produced in cell cultures in vitro. As NoVs infecting human population are highly divergent, it is proposed that the vaccine should contain at least two different NoV genotypes, potentially affecting the immunogenicity of each other. We investigated the immunogenicity of NoV GII.4 VLPs administered by intramuscular (IM) or intradermal (ID) injections to BALB/c mice either alone or co-delivered with genogroup I (GI) and other genogroup GII VLPs. Serum NoV-specific IgG binding antibody titers and antibody functionality in terms of avidity and blocking potential were assessed. Furthermore, the specificity and functional avidity of CD4+ and CD8+ T cell responses were analyzed using synthetic peptides previously identified to contain NoV VP1 P2 domain-specific H-2d epitopes. The results showed that IM and ID immunization induced comparable GII.4-specific antibodies and T cell responses. Similar magnitude and functionality of antibodies and interferon-gamma producing T cells were developed using monovalent GII.4 VLPs or different genotype combinations. For the first time, degranulation assay using multicolor flow cytometry showed that NoV GII.4-specific CD8+ T cells had cytotoxic T lymphocyte phenotype. To conclude, our results demonstrate that there is no immunological interference even if up to five different NoV VLP genotypes were co-administered at the same time. Furthermore, no inhibition of NoV-specific antibody functionality or the magnitude, specificity and affinity of T cell responses was observed in any of the immunized animals, observations relevant for the development of a multivalent NoV VLP vaccine.
Assuntos
Anticorpos Antivirais/imunologia , Infecções por Caliciviridae/imunologia , Gastroenterite/imunologia , Norovirus/imunologia , Linfócitos T/imunologia , Vacinas de Partículas Semelhantes a Vírus/imunologia , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Especificidade de Anticorpos/imunologia , Infecções por Caliciviridae/virologia , Degranulação Celular/imunologia , Reações Cruzadas , Epitopos/imunologia , Gastroenterite/virologia , Genótipo , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Camundongos , Norovirus/genética , Peptídeos/imunologia , Proteínas Recombinantes/imunologia , Especificidade do Receptor de Antígeno de Linfócitos T , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Linfócitos T/metabolismo , Vacinas Virais/imunologiaRESUMO
Recombinant proteins produced by baculovirus (BV) expression systems contain residual BV after crude purification. We studied adjuvant effect of BV on antibody and T cell responses against two model antigens, monomeric ovalbumin (OVA) protein and oligomeric norovirus (NoV) virus-like particles (VLPs). BALB/c mice were immunized intradermally with OVA alone or OVA formulated with live or inactivated BV, and VLP formulations comprised of chromatographically purified NoV GII.4 VLPs alone or mixed with BV, or of crude purified VLPs containing BV impurities from expression system. Live BV improved immunogenicity of NoV VLPs, sparing VLP dose up to 10-fold. Moreover, soluble OVA protein induced IgG2a antibodies and T cell response only when co-administered with live BV. BV adjuvant effect was completely abrogated by removal or inactivation of BV. These findings support the usage of crude purified proteins containing residual BV as vaccine antigens.
Assuntos
Adjuvantes Imunológicos/metabolismo , Linfócitos B/imunologia , Baculoviridae/metabolismo , Norovirus/imunologia , Ovalbumina/imunologia , Linfócitos T/imunologia , Virossomos/imunologia , Animais , Injeções Intradérmicas , Camundongos Endogâmicos BALB C , Ovalbumina/administração & dosagem , Virossomos/administração & dosagemRESUMO
Norovirus (NoV)-specific serum antibodies bind to NoV-derived virus-like particles (VLPs) and block the binding of VLPs to the host cell attachment factors/receptors, histo-blood group antigens (HBGAs). Blocking antibodies in human sera have been associated with a protection from NoV infection and disease. Studies of experimental NoV VLP-based vaccines measure blocking antibodies in animal sera instead of a traditional virus neutralization assay. This chapter describes the methodology for analyzing blocking antibodies from NoV GII.4 VLP-immunized mouse sera. Protocol for obtaining mouse NoV GII.4-specific immune sera is described, followed by the detailed protocol for blocking assay using synthetic HBGAs.
Assuntos
Anticorpos Bloqueadores/imunologia , Anticorpos Antivirais/imunologia , Infecções por Caliciviridae/imunologia , Animais , Anticorpos Antivirais/sangue , Formação de Anticorpos , Infecções por Caliciviridae/sangue , Camundongos , Norovirus/imunologiaRESUMO
Norovirus (NoV) is a leading cause of acute gastroenteritis in people of all ages worldwide. NoV-specific serum antibodies which block the binding of NoV virus-like particles (VLPs) to the cell receptors have been thoroughly investigated. In contrast, only a few publications are available on the NoV capsid VP1 protein-specific T cell responses in humans naturally infected with the virus. Freshly isolated peripheral blood mononuclear cells of eight healthy adult human donors previously exposed to NoV were stimulated with purified VLPs derived from NoV GII.4-1999, GII.4-2012 (Sydney), and GI.3, and IFN-γ production was measured by an ELISPOT assay. In addition, 76 overlapping synthetic peptides spanning the entire 539-amino acid sequence of GII.4 VP1 were pooled into two-dimensional matrices and used to identify putative T cell epitopes. Seven of the eight subjects produced IFN-γ in response to the peptides and five subjects produced IFN-γ in response to the VLPs of the same origin. In general, stronger T cell responses were induced with the peptides in each donor compared to the VLPs. A CD8+ T cell epitope in the shell domain of the VP1 (134SPSQVTMFPHIIVDVRQL151) was identified in two subjects, both having human leukocyte antigen (HLA)-A∗02:01 allele. To our knowledge, this is the first report using synthetic peptides to study NoV-specific T cell responses in human subjects and identify T cell epitopes.
RESUMO
Norovirus (NoV)-specific antibodies, which block binding of the virus-like particles (VLPs) to the cell receptors are conformation dependent and directed towards the most exposed domain of the NoV capsid VP1 protein, the P2 domain. Limited data are available on the antibodies directed to other domains of the VP1, and even less on the NoV VP1-specific T cell epitopes. In here, BALB/c mice were immunized with six VLPs derived from NoV GII.4-1999, GII.4-2009 (New Orleans), GII.4-2012 (Sydney), GII.12, GI.1, and G1.3. Serum immunoglobulin G binding antibodies, histo-blood group antigen blocking antibodies and T cell responses using type-specific and heterologous NoV VLPs, P-dimers and 76 overlapping synthetic peptides, spanning the entire 539 amino acid sequence of GII.4 VP1, were determined. The results showed that at least half of the total antibody content is directed towards conserved S domain of the VP1. Only a small fraction (<1%) of the VP1 binding antibodies were blocking/neutralizing. With the use of matrix peptide pools and individual peptides, seven CD4+ and CD8+ T cell restricted epitopes were mapped, two located in S domain, four in P2 domain and one in P1 domain of NoV VP1. The epitopes were GII.4 strain-specific but also common GII.4 genotype-specific T cell epitopes were identified. More importantly, the results suggest a 9-amino acids long sequence (318PAPLGTPDF326) in P2 domain of VP1 as a universal NoV genogroup II-specific CD8+ T cell epitope. Distribution of the T cell epitopes alongside the capsid VP1 indicates the need of the complete protein for high immunogenicity.