RESUMEN
Malaria remains a global health challenge, necessitating the development of effective vaccines. The RTS,S vaccination prevents Plasmodium falciparum (Pf) malaria but is ineffective against Plasmodium vivax (Pv) disease. Herein, we evaluated the murine immunogenicity of a recombinant PvCSP incorporating prevalent polymorphisms, adjuvanted with Alhydrogel or Poly I:C. Both formulations induced prolonged IgG responses, with IgG1 dominance by the Alhydrogel group and high titers of all IgG isotypes by the Poly I:C counterpart. Poly I:C-adjuvanted vaccination increased splenic plasma cells, terminally-differentiated memory cells (MBCs), and precursors relative to the Alhydrogel-combined immunization. Splenic B-cells from Poly I:C-vaccinated mice revealed an antibody-secreting cell- and MBC-differentiating gene expression profile. Biological processes such as antibody folding and secretion were highlighted by the Poly I:C-adjuvanted vaccination. These findings underscore the potential of Poly I:C to strengthen immune responses against Pv malaria.
Asunto(s)
Adyuvantes de Vacunas , Hidróxido de Aluminio , Inmunogenicidad Vacunal , Vacunas contra la Malaria , Malaria Vivax , Plasmodium vivax , Poli I-C , Proteínas Protozoarias , Poli I-C/administración & dosificación , Plasmodium vivax/inmunología , Inmunidad Humoral , Inmunidad Celular , Proteínas Protozoarias/inmunología , Vacunas contra la Malaria/química , Vacunas contra la Malaria/inmunología , Hidróxido de Aluminio/administración & dosificación , Inmunoglobulina G/sangre , Masculino , Animales , Células Plasmáticas/inmunología , Femenino , Ratones Endogámicos C57BL , Proteínas Recombinantes/inmunología , Vacunación , Adyuvantes de Vacunas/administración & dosificación , Malaria Vivax/prevención & controlRESUMEN
Malaria caused byPlasmodium vivaxis a pressing public health problem in tropical and subtropical areas.However, little progress has been made toward developing a P. vivaxvaccine, with only three candidates being tested in clinical studies. We previously reported that one chimeric recombinant protein (PvCSP-All epitopes) containing the conserved C-terminus of the P. vivax Circumsporozoite Protein (PvCSP), the three variant repeat domains, and aToll-like receptor-3 agonist,Poly(I:C), as an adjuvant (polyinosinic-polycytidylic acid, a dsRNA analog mimicking viral RNA), elicits strong antibody-mediated immune responses in mice to each of the three allelic forms of PvCSP. In the present study, a pre-clinical safety evaluation was performed to identify potential local and systemic toxic effects of the PvCSP-All epitopes combined with the Poly-ICLC (Poly I:C plus poly-L-lysine, Hiltonol®) or Poly-ICLC when subcutaneously injected into C57BL/6 mice and New Zealand White Rabbits followed by a 21-day recovery period. Overall, all observations were considered non-adverse and were consistent with the expected inflammatory response and immune stimulation following vaccine administration. High levels of vaccine-induced specific antibodies were detected both in mice and rabbits. Furthermore, mice that received the vaccine formulation were protected after the challenge with Plasmodium berghei sporozoites expressing CSP repeats from P. vivax sporozoites (Pb/Pv-VK210). In conclusion, in these non-clinical models, repeated dose administrations of the PvCSP-All epitopes vaccine adjuvanted with a Poly-ICLC were immunogenic, safe, and well tolerated.
Asunto(s)
Carboximetilcelulosa de Sodio/análogos & derivados , Vacunas contra la Malaria , Malaria Vivax , Polilisina/análogos & derivados , Ratones , Animales , Conejos , Malaria Vivax/prevención & control , Poli I-C , Plasmodium vivax , Proteínas Protozoarias/genética , Ratones Endogámicos C57BL , Adyuvantes Inmunológicos , Proteínas Recombinantes , Epítopos , Anticuerpos AntiprotozoariosRESUMEN
Two years ago, we held an exciting event entitled the São Paulo School of Advanced Sciences on Vaccines (SPSASV). Sixty-eight Ph.D. students, postdoctoral fellows and independent researchers from 37 different countries met at the Mendes Plaza Hotel located in the city of Santos, SP - Brazil to discuss the challenges and the new frontiers of vaccinology. The SPSASV provided a critical and comprehensive view of vaccine research from basics to the current state-of-the-art techniques performed worldwide. For 10 days, we discussed all the aspects of vaccine development in 36 lectures, 53 oral presentations and 2 poster sessions. At the end of the course, participants were further encouraged to present a model of a grant proposal related to vaccine development against individual pathogens. Among the targeted pathogens were viruses (Chikungunya, HIV, RSV, and Influenza), bacteria (Mycobacterium tuberculosis and Streptococcus pyogenes), parasites (Plasmodium falciparum or Plasmodium vivax), and the worm Strongyloides stercoralis. This report highlights some of the knowledge shared at the SPSASV.(AU)
Asunto(s)
Instituciones Académicas , Vacunas , Técnicas Inmunológicas/métodos , Informe de Investigación , Vacunología , Concentración de Iones de HidrógenoRESUMEN
Recently, we generated two bacterial recombinant proteins expressing 89 amino acids of the C-terminal domain of the Plasmodium vivax merozoite surface protein-1 and the hexa-histidine tag (His6MSP1(19)). One of these recombinant proteins contained also the amino acid sequence of the universal pan allelic T-cell epitope (His6MSP1(19)-PADRE). In the present study, we evaluated the immunogenic properties of these antigens when administered via the intra-nasal route in the presence of distinct adjuvant formulations. We found that C57BL/6 mice immunized with either recombinant proteins in the presence of the adjuvants cholera toxin (CT) or the Escherichia coli heat labile toxin (LT) developed high and long lasting titers of specific serum antibodies. The induced immune responses reached maximum levels after three immunizing doses with a prevailing IgG1 subclass response. In contrast, mice immunized by intranasal route with His6MSP1(19)-PADRE in the presence of the synthetic oligonucleotides adjuvant CpG ODN 1826 developed lower antibody titers but when combined to CT, CpG addition resulted in enhanced IgG responses characterized by lower IgG1 levels. Considering the limitations of antigens formulations that can be used in humans, mucosal adjuvants can be a reliable alternative for the development of new strategies of immunization using recombinant proteins of P. vivax.
Asunto(s)
Humanos , Animales , Femenino , Ratones , Inmunoglobulina G/inmunología , Vacunas contra la Malaria/inmunología , Malaria Vivax/inmunología , Proteína 1 de Superficie de Merozoito/inmunología , Plasmodium vivax/inmunología , Adyuvantes Inmunológicos , Administración Intranasal , Inmunidad Celular/inmunología , Inmunidad Mucosa/efectos de los fármacos , Inmunoglobulina G/sangre , Vacunas contra la Malaria/administración & dosificación , Malaria Vivax/prevención & control , Proteína 1 de Superficie de Merozoito/administración & dosificación , Proteína 1 de Superficie de Merozoito/genética , Proteínas Recombinantes/inmunología , Vacunas Sintéticas/inmunologíaRESUMEN
In previous immuno-epidemiological studies of the naturally acquired antibody responses to merozoite surface protein-1 (MSP-1) of Plasmodium vivax, we had evidence that the responses to distinct erythrocytic stage antigens could be differentially regulated. The present study was designed to compare the antibody response to three asexual erythrocytic stage antigens vaccine candidates of P. vivax. Recombinant proteins representing the 19 kDa C-terminal region of MSP-1(PvMSP19), apical membrane antigen n-1 ectodomain (PvAMA-1), and the region II of duffy binding protein (PvDBP-RII) were compared in their ability to bind to IgG antibodies of serum samples collected from 220 individuals from the state of Pará, in the North of Brazil. During patent infection with P. vivax, the frequency of individuals with IgG antibodies to PvMSP1(19), PvAMA-1, and PvDBP-RII were 95, 72.7, and 44.5 percent respectively. Although the frequency of responders to PvDBP-RII was lower, this frequency increased in individuals following multiple malarial infections. Individually, the specific antibody levels did not decline significantly nine months after treatment, except to PvMSP1(19). Our results further confirm a complex regulation of the immune response to distinct blood stage antigens. The reason for that is presently unknown but it may contribute to the high risk of re-infection in individuals living in the endemic areas.
Asunto(s)
Humanos , Animales , Anticuerpos Antiprotozoarios/inmunología , Inmunoglobulina G/inmunología , Malaria Vivax/inmunología , Proteína 1 de Superficie de Merozoito/inmunología , Plasmodium vivax/inmunología , Ensayo de Inmunoadsorción Enzimática , Proteína 1 de Superficie de Merozoito/química , Proteínas Recombinantes/inmunologíaRESUMEN
Obligatory intracellular parasites such as Plasmodium sp, Trypanosoma cruzi, Toxoplasma gondii and Leishmania sp are responsible for the infection of hundreds of millions of individuals every year. These parasites can deliver antigens to the host cell cytoplasm that are presented through MHC class I molecules to protective CD8 T cells. The in vivo priming conditions of specific CD8 T cells during natural infection are largely unknown and remain as an area that has been poorly explored. The antiparasitic mechanisms mediated by CD8 T cells include both interferon-g-dependent and -independent pathways. The fact that CD8 T cells are potent inhibitors of parasitic development prompted many investigators to explore whether induction of these T cells can be a feasible strategy for the development of effective subunit vaccines against these parasitic diseases. Studies performed on experimental models supported the hypothesis that CD8 T cells induced by recombinant viral vectors or DNA vaccines could serve as the basis for human vaccination. Regimens of immunization consisting of two different vectors (heterologous prime-boost) are much more efficient in terms of expansion of protective CD8 T lymphocytes than immunization with a single vector. The results obtained using experimental models have led to clinical vaccination trials that are currently underway
Asunto(s)
Animales , Humanos , Ratones , Antígenos de Protozoos , Linfocitos T CD8-positivos , Inmunización , Infecciones por Protozoos , Vacunas Antiprotozoos , Inmunidad Celular , Vacunas de ADNRESUMEN
A proteína de superfície de merozoítos-1 (MSP-1) é um dos principais antígenos candidatos à vacina contra a fase assexuada sanguínea da malária. nesta revisäo analisamos dados disponíveis sobre a extensäo da diversidade da MSP-1 em populaçoes naturais de P. falciparum e P. vivax, e o potencial impacto desta diversidade sobre o reconhecimeno imunológico deste antígeno por pacientes com malária. Emfatizamos os dados recentemente obtidos durante estudos realizados na Amazônia brasileira, onde ambas as espécies de parasita säo prevalentes. Os dados moleculares e imunológicos säo discutidos em relaçäo à biologia da populaçäo de parasitas e possíveis estratégias para o desenvolvimento de uma vacina contra a malária baseada na MSP-1.