Efeito da sílica nanoestruturada SBA-15 como veículo protetor em imunizações com Toxoide Tetânico

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.