RESUMO
Several COVID-19 vaccines use adenovirus vectors to deliver the SARS-CoV-2 spike (S) protein. Immunization with these vaccines promotes immunity against the S protein, but against also the adenovirus itself. This could interfere with the entry of the vaccine into the cell, reducing its efficacy. Herein, we evaluate the efficiency of an adenovirus-vectored vaccine (chimpanzee ChAdOx1 adenovirus, AZD1222) in boosting the specific immunity compared to that induced by a recombinant receptor-binding domain (RBD)-based vaccine without viral vector. Mice immunized with the AZD1222 human vaccine were given a booster 6 months later, with either the homologous vaccine or a recombinant vaccine based on RBD of the delta variant, which was prevalent at the start of this study. A significant increase in anti-RBD antibody levels was observed in rRBD-boosted mice (31-61%) compared to those receiving two doses of AZD1222 (0%). Significantly higher rates of PepMix™- or RBD-elicited proliferation were also observed in IFNγ-producing CD4 and CD8 cells from mice boosted with one or two doses of RBD, respectively. The lower efficiency of the ChAdOx1-S vaccine in boosting specific immunity could be the result of a pre-existing anti-vector immunity, induced by increased levels of anti-adenovirus antibodies found both in mice and humans. Taken together, these results point to the importance of avoiding the recurrent use of the same adenovirus vector in individuals with immunity and memory against them. It also illustrates the disadvantages of ChAdOx1 adenovirus-vectored vaccine with respect to recombinant protein vaccines, which can be used without restriction in vaccine-booster programs. KEY POINTS: ⢠ChAdOx1 adenovirus vaccine (AZD1222) may not be effective in boosting anti-SARS-CoV-2 immunity ⢠A recombinant RBD protein vaccine is effective in boosting anti-SARS-CoV-2 immunity in mice ⢠Antibodies elicited by the rRBD-delta vaccine persisted for up to 3 months in mice.
Assuntos
Vacinas contra Adenovirus , COVID-19 , Vacinas , Humanos , Animais , Camundongos , Pan troglodytes , ChAdOx1 nCoV-19 , Vacinas contra COVID-19/genética , SARS-CoV-2 , COVID-19/prevenção & controle , Adenoviridae/genética , Vacinação , Anticorpos Antivirais , Anticorpos NeutralizantesRESUMO
Epidemiological studies showed that Alzheimer's disease (AD) and cerebral amyloid angiopathy (CAA) frequently co-occur; however, the precise mechanism is not well understood. A unique animal model (Tg-SwDI mice) was developed to investigate the early-onset and robust accumulation of both parenchymal and vascular Aß in the brain. Tg-SwDI mice have been extensively used to study the mechanisms of cerebrovascular dysfunction, neuroinflammation, neurodegeneration, and cognitive decline observed in AD/CAA patients and to design biomarkers and therapeutic strategies. In the present study, we documented interesting new features in the thalamus of Tg-SwDI mice: 1) a sharp increase in the expression of ionized calcium-binding adapter molecule 1 (Iba-1) in microglia in 6-month-old animals; 2) microglia clustering at six months that disappeared in old animals; 3) N-truncated/modified AßN3(pE) peptide in 9-month-old female and 12-month-old male mice; 4) an age-dependent increase in translocator protein (TSPO) expression. These findings reinforce the versatility of this model for studying multiple pathological issues involved in AD and CAA.
Assuntos
Doença de Alzheimer , Angiopatia Amiloide Cerebral , Animais , Feminino , Masculino , Camundongos , Doença de Alzheimer/complicações , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides , Encéfalo/metabolismo , Angiopatia Amiloide Cerebral/complicações , Angiopatia Amiloide Cerebral/genética , Angiopatia Amiloide Cerebral/metabolismo , Modelos Animais de Doenças , Camundongos Transgênicos , Microglia/metabolismo , Ácido Pirrolidonocarboxílico/metabolismo , Ácido Pirrolidonocarboxílico/uso terapêutico , Tálamo/metabolismoRESUMO
Polyhedrins are viral proteins present in a large family of baculoviruses that form occlusion bodies (polyhedra). These structures protect the virus particles from the outside environment until they are ingested by susceptible insects. Occluded viruses can sustain inclement weather for long periods of time. Therefore, the polyhedra is a natural preservative that keeps the viral structure intact at ambient temperature for years. In a previous study we identified the first 110 amino acids from polyhedrin (PH(1-110)) as a good candidate to carry antigens of interest. As a proof of concept, we produced a fusion protein with PH(1-110) and the green fluorescent protein (PH(1-110)GFP). The fusion protein associates spontaneously during its synthesis resulting in the formation of nanoparticles. Nasal immunization with these nanoparticles and in the absence of any adjuvant, results in a robust immune response with the production of IgG immunoglobulins that remained elevated for months and that selectively recognize the GFP but not PH(1-110). These results indicate that PH(1-110) is poorly immunogenic but capable of enhancing the immune response to GFP.
Assuntos
Nanopartículas , Vacinas , Temperatura , Antígenos , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismoRESUMO
It is well documented that sporadic Alzheimer's disease (AD) is a multifactorial disease and considered to be a result of several pathological events, both in the periphery and in the brain. The role of the peripheral immune system in the etiology and/or progression of the disease is not fully understood yet, and the results in humans are contradictory so far. Several animal models of AD have been generated and thoroughly characterized to elucidate disease mechanisms and evaluate numerous therapeutic strategies in preclinical studies. In the present study, we carried out a longitudinal evaluation of blood lymphocytes from male and female 3xTg-AD mice to document important immunological abnormalities in the periphery. We documented the age-dependent decrease in the percentage of CD3+ and CD4+ lymphocytes and an increase in the percentage CD3+CD4-CD8- (DN T) cells in the blood of 3xTg-AD mice compared with non-transgenic animals. Severe splenomegaly was observed in 3xTg-AD mice in contrast to wild-type animals. Importantly, all these abnormalities in the peripheral immune system appeared earlier and were more pronounced in males compared with females of the same age, which may account for the shorter lifespan of male mice. We suggest that future research should include the measurement of CD3+ and DN T cells as a potential immunological marker of disease progression in AD patients.
Assuntos
Envelhecimento/imunologia , Doença de Alzheimer/imunologia , Contagem de Linfócitos , Caracteres Sexuais , Subpopulações de Linfócitos T/imunologia , Envelhecimento/sangue , Doença de Alzheimer/sangue , Animais , Complexo CD3/análise , Antígenos CD4/análise , Antígenos CD8/análise , Modelos Animais de Doenças , Progressão da Doença , Feminino , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Subpopulações de Linfócitos T/químicaRESUMO
In addition to the full-length beta-amyloid peptides (Aß 1-40/42), several Aß variants, truncated at their N- or C-termini and bearing different post-translational modifications, have been detected in the brain of Alzheimer´s disease (AD) patients. AßN3(pE), an Aß peptide bearing an amino-terminal pyroglutamate at position 3, is a significant constituent of intracellular, extracellular and vascular Aß deposits in brain tissue from individuals with AD and Down syndrome. Pioneering immunotherapy studies have primarily focused on the full-length Aß peptide, disregarding the presence of N-truncated/modified species. However, in recent years, increasing attention has been directed towards AßN3(pE), in both pre-clinical studies and clinical trials. In the present study, we generated and characterized an anti-AßN3(pE) mouse monoclonal antibody (3B8) that recognizes amyloid aggregates in brain tissue from AD patients and in 3xTg-AD transgenic mice. To identify the epitope recognized by 3B8, a library of random heptapeptides fused to the minor coat protein of M13 phage was screened. Results from screening, along with those from ELISA assays against distinct Aß fragments, suggest recognition of two conformational epitopes present in AßN3(pE) and Aß 3-42, regardless of the glutamate-pyroglutamate modification. The novel 3B8 antibody may be useful in future therapeutic and diagnostic applications for AD.
Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Anticorpos Monoclonais/metabolismo , Encéfalo/metabolismo , Fragmentos de Peptídeos/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/genética , Animais , Anticorpos Monoclonais/genética , Epitopos/genética , Epitopos/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Fragmentos de Peptídeos/genéticaRESUMO
BACKGROUND: The use of biomaterials has been expanded to improve the characteristics of vaccines. Recently we have identified that the peptide PH(1-110) from polyhedrin self-aggregates and incorporates foreign proteins to form particles. We have proposed that this peptide can be used as an antigen carrying system for vaccines. However, the immune response generated by the antigen fused to the peptide has not been fully characterized. In addition, the adjuvant effect and thermostability of the particles has not been evaluated. RESULTS: In the present study we demonstrate the use of a system developed to generate nano and microparticles carrying as a fusion protein peptides or proteins of interest to be used as vaccines. These particles are purified easily by centrifugation. Immunization of animals with the particles in the absence of adjuvant result in a robust and long-lasting immune response. Proteins contained inside the particles are maintained for over 1 year at ambient temperature, preserving their immunological properties. CONCLUSION: The rapid and efficient production of the particles in addition to the robust immune response they generate position this system as an excellent method for the rapid response against emerging diseases. The thermostability conferred by the particle system facilitates the distribution of the vaccines in developing countries or areas with no electricity.
Assuntos
Antígenos/imunologia , Imunoglobulinas/metabolismo , Proteínas de Matriz de Corpos de Inclusão/química , Peptídeos/química , Vacinas/imunologia , Animais , Antígenos/química , Estabilidade de Medicamentos , Feminino , Proteínas de Fluorescência Verde/química , Proteínas de Fluorescência Verde/imunologia , Imunização , Camundongos , Nanopartículas , Tamanho da Partícula , Agregados Proteicos , Proteínas Recombinantes de Fusão/imunologia , Termodinâmica , Vacinas/químicaRESUMO
It has been demonstrated that peripheral infections accompanied by neuroinflammation may modify brain development or affect normal brain aging and represent major risk factors for the development of neurological disorders. A wide range of synthetic and natural compounds with anti-inflammatory properties have been evaluated in animal models of neuroinflammation and neurodegeneration as an adjuvant therapeutic strategy. In the present study we have demonstrated for the first time that sodium thiosulphate (STS), a known antidote approved for treatment of certain medical conditions, is capable of reducing brain inflammation caused by systemic LPS administration. STS reduced brain levels of pro-inflammatory cytokine interleukin-1ß (IL-1ß), cyclooxygenase-2 (COX-2), ionized calcium binding adaptor molecule 1 (Iba-1) and 18 kDa translocator protein (TSPO) in an animal model of systemic LPS-induced neuroinflammation. In addition, we demonstrated for the first time elevated TSPO expression in retinal ganglion cells layer after peripheral LPS challenge and inhibition of ocular TSPO expression after treatment with STS. We think that STS may be used as an adjuvant anti-inflammatory therapy for many pathological conditions associated with inflammation in the brain.
RESUMO
Neuroinflammation is an important feature in the pathogenesis and progression of neurodegenerative diseases. Molecules with anti-inflammatory properties have been evaluated in animal models of neuroinflammation and neurodegeneration as an adjuvant therapeutic strategy. In the present study we have demonstrated that alpha-mangostin (α-MG), a natural xanthone purified from mangosteen pericarp, reduced brain levels of pro-inflammatory cytokine interleukin-6 (IL-6), cyclooxygenase-2 (COX-2) and 18 kDa translocator protein (TSPO) in an animal model of peripheral LPS-induced neuroinflammation. We think that evaluation of α-MG as an adjuvant treatment in preclinical models of AD, PD, multiple sclerosis and other diseases with known shared pathology merits further consideration.
Assuntos
Anti-Inflamatórios/uso terapêutico , Encefalite/induzido quimicamente , Encefalite/tratamento farmacológico , Lipopolissacarídeos/toxicidade , Xantonas/uso terapêutico , Análise de Variância , Animais , Proteínas de Ligação ao Cálcio/metabolismo , Ciclo-Oxigenase 2/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Encefalite/patologia , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Proteína Glial Fibrilar Ácida/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Proteínas dos Microfilamentos/metabolismo , Microglia/efeitos dos fármacos , Receptores de GABA/metabolismoRESUMO
The main amyloid-ß peptide (Aß) variants detected in the human brain are Aß1-40 and Aß1-42; however, a significant proportion of Aß in Alzheimer's disease (AD) brain also consists of N-terminal truncated/modified species. AßN3(pE), Aß peptide bearing amino-terminal pyroglutamate at position 3, has been demonstrated to be a major N-truncated/modified constituent of intracellular, extracellular, and vascular Aß deposits in AD and Down syndrome brain tissue. It has been previously demonstrated that rabbits fed a diet enriched in cholesterol and given water containing trace copper levels developed AD-like pathology including intraneuronal and extracellular Aß accumulation, tau hyperphosphorylation, vascular inflammation, astrocytosis, microgliosis, reduced levels of acetylcholine, as well as learning deficits and thus, may be used as a non-transgenic animal model of sporadic AD. In the present study, we have demonstrated for the first time the presence of AßN3(pE) in blood vessels in cholesterol-enriched diet-fed rabbit brain. In addition, we detected AßN3(pE) immunoreactivity in all postmortem AD brain samples studied. We believe that our results are potentially important for evaluation of novel therapeutic molecules/strategies targeting Aß peptides in a suitable non-transgenic animal model.
Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Encéfalo/irrigação sanguínea , Encéfalo/metabolismo , Colesterol na Dieta/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Animais , Anticorpos/metabolismo , Astrócitos/metabolismo , Córtex Cerebral/irrigação sanguínea , Córtex Cerebral/metabolismo , Espaço Extracelular/metabolismo , Hipocampo/irrigação sanguínea , Hipocampo/metabolismo , Humanos , Espaço Intracelular/metabolismo , Masculino , Camundongos , Camundongos Transgênicos , Neurônios/metabolismo , Fragmentos de Peptídeos/metabolismo , CoelhosRESUMO
N-truncated/modified forms of amyloid beta (Aß) peptide are found in diffused and dense core plaques in Alzheimer's disease (AD) and Down's syndrome patients as well as animal models of AD, and represent highly desirable therapeutic targets. In the present study we have focused on N-truncated/modified Aß peptide bearing amino-terminal pyroglutamate at position 11 (AßN11(pE)). We identified two B-cell epitopes recognized by rabbit anti-AßN11(pE) polyclonal antibodies. Interestingly, rabbit anti-AßN11(pE) polyclonal antibodies bound also to full-length Aß1-42 and N-truncated/modified AßN3(pE), suggesting that the three peptides may share a common B-cell epitope. Importantly, rabbit anti-AßN11(pE) antibodies bound to naturally occurring Aß aggregates present in brain samples from AD patients. These results are potentially important for developing novel immunogens for targeting N-truncated/modified Aß aggregates as well, since the most commonly used immunogens in the majority of vaccine studies have been shown to induce antibodies that recognize the N-terminal immunodominant epitope (EFRH) of the full length Aß, which is absent in N-amino truncated peptides.
Assuntos
Peptídeos beta-Amiloides/metabolismo , Anticorpos/farmacologia , Linfócitos B/imunologia , Epitopos de Linfócito B/efeitos dos fármacos , Ácido Pirrolidonocarboxílico/imunologia , Doença de Alzheimer/patologia , Análise de Variância , Animais , Anticorpos Anti-Idiotípicos/imunologia , Anticorpos Anti-Idiotípicos/metabolismo , Linfócitos B/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/patologia , Linhagem Celular Tumoral , Ensaio de Imunoadsorção Enzimática/métodos , Epitopos de Linfócito B/imunologia , Humanos , Neuroblastoma/patologia , Ligação Proteica/efeitos dos fármacos , CoelhosRESUMO
In search of reducing vaccine production costs', a recombinant M13 phage version of the anti-cysticercosis tripeptide vaccine (S3Pvac) was developed. The efficacy of S3Pvac-Phage vs. placebo was evaluated in a randomized trial that included 1,047 rural pigs in 16 villages of Central Mexico. Three to five months after vaccination 530 pigs were examined by tongue inspection. At 5-27 months of age, 331 pigs (197 vaccinated/134 controls) were inspected at necropsy. Vaccination reduced 70% the frequency of tongue cysticercosis and, based on necropsy, 54% of muscle-cysticercosis and by 87% the number of cysticerci.
Assuntos
Antígenos de Helmintos/imunologia , Bacteriófago M13/imunologia , Cisticercose/imunologia , Cisticercose/veterinária , Doenças dos Suínos/imunologia , Doenças dos Suínos/prevenção & controle , Taenia solium/imunologia , Vacinas/imunologia , Vacinas/uso terapêutico , Envelhecimento/imunologia , Animais , Antígenos de Helmintos/biossíntese , Bacteriófago M13/metabolismo , Cisticercose/prevenção & controle , México , População Rural , Suínos , Doenças dos Suínos/parasitologia , Vacinas de Produtos Inativados/imunologia , Aumento de Peso/efeitos dos fármacosRESUMO
Vaccination of pigs may curtail Taenia solium transmission by reducing the number of cysticerci, the precursors of adult intestinal tapeworms in humans. Several antigen preparations induce protection against porcine cysticercosis in experimental settings but only one subunit vaccine (S3Pvac) has been tested and proved effective in the field against naturally acquired disease. Besides improving of the vaccine's effectiveness, significant reductions in production costs and in the logistics of its administration are necessary for the feasibility of nationwide control programs. This review highlights the development of several versions of S3Pvac aimed to increase effectiveness, reduce costs and increase feasibility by novel delivery systems and alternative routes of administration.
Assuntos
Cisticercose/veterinária , Doenças dos Suínos/prevenção & controle , Taenia solium/imunologia , Vacinação/veterinária , Vacinas de Subunidades Antigênicas/uso terapêutico , Animais , Cisticercose/parasitologia , Cisticercose/prevenção & controle , Cisticercose/transmissão , Suínos , Doenças dos Suínos/imunologia , Doenças dos Suínos/parasitologia , Doenças dos Suínos/transmissão , Vacinação/economia , Vacinação/métodos , Vacinas de Subunidades Antigênicas/economia , Vacinas de Subunidades Antigênicas/imunologia , Vacinas Sintéticas/economia , Vacinas Sintéticas/imunologia , Vacinas Sintéticas/uso terapêuticoRESUMO
Cell-surface saccharides of Mycobacterium tuberculosis appear to be crucial factors in tuberculosis pathogenicity and could be useful antigens in tuberculosis immunodiagnosis. In the present study, we report the successful antigenic and immunogenic mimicry of mannose-containing cell-wall compounds of M. tuberculosis by dodecamer peptides identified by phage-display technology. Using a rabbit antiserum raised against M. tuberculosis cell-surface saccharides as a target for biopanning, peptides with three different consensus sequences were identified. Phage-displayed and chemically synthesized peptides bound to the anticarbohydrate antiserum. Rabbit antibodies elicited against the peptide QEPLMGTVPIRAGGGS recognize the mannosylated M. tuberculosis cell-wall antigens arabinomannan and lipoarabinomannan, and the glycosylated recombinant protein alanine/proline-rich antigen. Furthermore, antibodies were also able to react with mannan from Saccharomyces cerevisiae, but not with phosphatidylinositol dimannosides or arabinogalactan from mycobacteria. These results suggest that the immunogenic peptide mimics oligomannosidic epitopes. Interestingly, this report provides evidence that, in contrast with previously known carbohydrate mimotopes, no aromatic residues are necessary in a peptide sequence for mimicking unusual glycoconjugates synthesized by mycobacteria. The possible usefulness of the identified peptide mimotopes as surrogate reagents for immunodiagnosis and for the study of functional roles of the native non-peptide epitopes is discussed.
Assuntos
Mimetismo Molecular/imunologia , Mycobacterium tuberculosis/imunologia , Peptídeos/química , Peptídeos/imunologia , Polissacarídeos Bacterianos/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Antibacterianos/biossíntese , Ensaio de Imunoadsorção Enzimática , Epitopos/química , Humanos , Dados de Sequência Molecular , Mycobacterium tuberculosis/química , Biblioteca de Peptídeos , CoelhosRESUMO
The aim of this study was to test the capacity of recombinant phages to deliver antigens for vaccination against porcine cysticercosis. Thus, three peptides (KETc1, KETc12, GK1) and a recombinant antigen KETc7, previously proven to induce high levels of protection against pig cysticercosis, were expressed on the surface of the M13 bacteriophage at multiple copies. The pool of these four recombinant phages induced high levels of protection against an experimental murine cysticercosis. The immunogenicity of the phage vaccine preparation was therefore, tested in pigs, the natural host of Taenia solium. Subcutaneous or oral vaccination with these phages induced antigen-specific cellular immune responses in pigs. Preliminary data also points to the protective capacity of this recombinant phage vaccine against pig cysticercosis. The immunogenicity of these recombinant phages, together with the low cost of their production, make them a realistic candidate to be tested in pigs as an anti-cysticercus phage vaccine for field trials. This is the first report describing the application of a filamentous bacteriophage as a vaccine in large animals such as pigs, the only intermediate hosts of T. solium, a parasite of major medical importance in developing countries. The potential application of phages as a modern platform for vaccines for human and animal diseases is discussed.