ABSTRACT
Routine immunization against diphtheria and tetanus has drastically reduced the incidence of these diseases worldwide. Anti-diphtheria/tetanus vaccine has in general aluminum salt as adjuvant in its formulation that can produce several adverse effects. There is a growing interest in developing new adjuvants. In this study, we evaluated the efficiency of SBA-15 as an adjuvant in subcutaneous immunization in mice with diphtheria (dANA) and tetanus (tANA) anatoxins as well as with the mixture of them (dtANA). The tANA molecules and their encapsulation in SBA-15 were characterized using Small-Angle X-ray Scattering (SAXS), Dynamical Light Scattering (DLS), Nitrogen Adsorption Isotherm (NAI), Conventional Circular Dichroism (CD)/Synchrotron Radiation Circular Dichroism (SRCD) Spectroscopy, and Tryptophan Fluorescence Spectroscopy (FS). The primary and secondary antibody response elicited by subcutaneous immunization of High (HIII) and Low (LIII) antibody responder mice with dANA, tANA, or dtANA encapsulated in the SBA-15 were determined. We demonstrated that SBA-15 increases the immunogenicity of dANA and tANA antigens, especially when administered in combination. We also verified that SBA-15 modulates the antibody response of LIII mice, turning them into high antibody responder. Thus, these results suggest that SBA-15 may be an effective adjuvant for different vaccine formulations.
Subject(s)
Diphtheria , Tetanus , Mice , Animals , Immunity, Humoral , Scattering, Small Angle , X-Ray Diffraction , Diphtheria/prevention & control , Tetanus/prevention & control , Tetanus Toxoid , Silicon Dioxide/pharmacology , Adjuvants, Immunologic/pharmacology , Immunization, Secondary/methods , Antibodies, BacterialABSTRACT
Routine immunization against diphtheria and tetanus has drastically reduced the incidence of these diseases worldwide. Anti-diphtheria/tetanus vaccine has in general aluminum salt as adjuvant in its formulation that can produce several adverse effects. There is a growing interest in developing new adjuvants. In this study, we evaluated the efficiency of SBA-15 as an adjuvant in subcutaneous immunization in mice with diphtheria (dANA) and tetanus (tANA) anatoxins as well as with the mixture of them (dtANA). The tANA molecules and their encapsulation in SBA-15 were characterized using Small-Angle X-ray Scattering (SAXS), Dynamical Light Scattering (DLS), Nitrogen Adsorption Isotherm (NAI), Conventional Circular Dichroism (CD)/Synchrotron Radiation Circular Dichroism (SRCD) Spectroscopy, and Tryptophan Fluorescence Spectroscopy (FS). The primary and secondary antibody response elicited by subcutaneous immunization of High (HIII) and Low (LIII) antibody responder mice with dANA, tANA, or dtANA encapsulated in the SBA-15 were determined. We demonstrated that SBA-15 increases the immunogenicity of dANA and tANA antigens, especially when administered in combination. We also verified that SBA-15 modulates the antibody response of LIII mice, turning them into high antibody responder. Thus, these results suggest that SBA-15 may be an effective adjuvant for different vaccine formulations.
ABSTRACT
Tetanus is a disease caused by Clostridium tetani, a gram-positive restricted anaerobic bacteria which produces the tetanus toxin called tetanospasmin. However, tetanus is easily preventable by subcutaneous (sc) vaccination (DTP, dT, DT and dTPa) usually adsorbed in aluminum hydroxide. These injectable vaccines presents some disadvantages such as pain during application, need for specialized staff and cold-chain thaw transportation. In this way, oral vaccination would be suitable due to its benefits like reduced production cost, easy transportation and better acceptance. Ordered mesoporous nanostructured silica SBA-15 is an immunogen protective vehicle candidate owing to the beneficial properties, such as the ability to associate with molecules, and chemical, thermal and hydrothermal stability. It has been demonstrated that the association of SBA-15 with several antigens, induce production of specific antibodies when injected through subcutaneous and eventual oral route. In this study, the objective was to verify the SBA-15 silica action as a protective carrier and effective adjuvant in immunizations with tetanus toxoid after subcutaneous and oral administration. Male and female mice from heterogeneous linages for low and high antibody production - LIII and HIII respectively - were used and also an isogenic linage Balb/c. They were immunized twice within 40 days of interval to get primary and secondary response. Results showed an adjuvant/protector effect of SBA-15 when the toxoid was inoculated through subcutaneous route, indicating specific IgG production levels on 30th day of primary response in all groups and progressive increase in secondary responses with the highest titers presented on the 30th day. However, oral immunizations didn’t show detectable IgG production in any group even after booster application.
O tétano é uma doença causada pelo Clostridium tetani, uma bactéria gram- positiva anaeróbia restrita que produz a neurotoxina tetânica, chamada tetanospasmina. No entanto, o tétano é facilmente prevenível através da vacinação (DTP, dT, DT e dTPa), realizada pela via subcutânea (sc), utilizando como adjuvante o hidróxido de alumínio. Entretanto, esse vacinas injetáveis apresentam certas desvantagens, como dor durante a aplicação, necessidade de pessoal especializado e transporte em cadeia a frio. Nesse sentido, a vacinação por via oral seria uma alternativa devido aos seus benefícios, como custo reduzido de produção, transporte facilitado e principalmente no que diz respeito à aceitação da população. A sílica mesoporosa nanoestruturada SBA-15 é candidata a veículo protetor de imunógeno devido às suas propriedades, como a habilidade se adsorver com moléculas e sua estabilidade química, térmica e hidrotérmica. Já foi demonstrado que a associação da SBA-15 com vários antígenos induz a produção de anticorpos específicos quando injetada por via subcutânea e, eventualmente, por via oral. Neste trabalho, o objetivo foi verificar a ação da SBA-15 como veículo protetor e adjuvante eficaz em imunizações com toxoide tetânico, também denominado anatoxina tetânica, após administração oral e subcutânea. Para tal, foram utilizados camundongos machos e fêmeas de linhagens heterogêneas geneticamente selecionadas para baixa e alta produção de anticorpos LIII e HIII, respectivamente, e de linhagem isogênica Balb/c, que foram imunizados duas vezes com um intervalo de 40 dias para obtenção das respostas primária (RP) e secundária (RS). Os resultados revelaram efeito adjuvante/protetor da SBA-15 quando o toxoide foi inoculado pela via subcutânea, mostrando produção de níveis IgG específicos no 30o dia de RP em todos os grupos e aumento gradual nas respostas secundárias, com os maiores títulos apresentados nas RS de 30 dias. Porém, nas imunizações pela via oral não foi detectada produção de IgG em nenhum grupo estudado, mesmo após a dose de reforço.
