Purificação, caracterização físico-química, atividades inflamatória e imunoadjuvante de alginatos da alga marinha Sargassum vulgare C. Agardh

Abstract

In the present work, it was made the characterization of two alginates -V and +V of the marine alga Sargassum vulgare, individualized on base in the viscosity and the mass molar. With the aim of determining their immunoadjuvant capacity, for a possible use in immunization protocols, these alginate were used to immunize "swiss" mice, associated to ovalbumin, as antigen. The immunizations were made through the oral, nasal and subcutaneous routes. For the subcutaneous route the alginates -V and +V, under the soluble form, potentiated the immune response of specific antibodies in level comparable to that of Al(OH)3. There was no difference in the titles of specific antibodies, along all the primary response in the presence of the two alginates, up to the 21St day after starting immunization. There was no increase of the secondary immune response against ovalbumin in the presence of the two alginates. -V and +V. There was a discret increase of the synthesis of specific IgE with the use of -V and +V and, in the presence of +V the response was, aparently earlier than in the presence of -V that was only revealed in secondary response. Furthermore, the secondary response, in the presence of +V, decreased less than the response in the presence of —V, after the 2nd booster. The two alginates were used as imunoadjuvants in the soluble and gel forms, for oral immunizations. With the use of both adjuvants, in the soluble form, they induced similar primary responses, up to the 15th day after starting immunization. With the adjuvantes under the gel form, contrarily, there was no potentiation of the primary response and the potentiation in the presence of -V as well as of +V it was only revealed after the 2nd booster, in the 30th day after the immunization. There was no synthesis of specific IgE in the oral immunizations with ovalbumin associated either to +V and -V in the soluble or gel forms. In the immunizations through nasal route, with the use of both alginates, synthesis of specific antibodies was not detected. The alginates - V and +V exerted pro-inflammatory effect, recruiting neutrophils and macrophages, by both subcutaneous air pouch or by peritoneal cavity, although in lower levels than the controls. Both alginates also provoked protein extravasation, but only the alginate +V was able to increase the vascular permeability. In spite of needing further experiments, based on the characteristics found for the two alginates, it is suggested that they can come to be used as adjuvants in protocols of vaccination.