Efeitos imunogênico, adjuvante e antifúngico da lectina de sementes de Lablab purpureus (L) SWEET e efeito antifúngico da lectina de sementes de Talisia esculenta (ST. HIL) RADLK

Abstract

This work was carried out with the overall aim of to investigate biological features of the lectin obtained from Lablab purpureum seeds (LLP) regarding to its immunogenic and adjuvant activities over humoral immune response in mice and its action on the growth of fungi Microsporum canis and Candida sp. compared to the effects of a fungistatic lectin obtained from Talisia esculenta seeds (TEL). Immune response was evaluated through ELISA. LLP showed to be immunogenic in a dose-dependent way, trigging off the production of specific antibodies in high levels after subcutaneous injection. It was also observed that anti-LLP antibodies profile was characterized by predominance of IgG class. Application of LLP conjugated to ovalbumin increased antibody production against this protein, being this effect more pronounced than that verified with the use of Al (OH)3, revealing that LLP possess expressive adjuvant action. The crude extracts (CE) obtained from L. purpureum seeds and the purified LLP were not able to inhibit significantly the growing of studied yeasts. Minimum inhibitory concentrations (MIC) calculated for CE and LLP achieved 250 and 1000 µg.mL-1, respectively, over 20 samples of M. canis tested. Even so, addition of carbohydrates D-glucose, D-manose and specially GIcNAc inhibited these antifungical effects. On the other hand, CE and LLP were able to inhibit the growth of artrosporated chitin-rich forms of M. canis obtained from infected animal hair and cultured in Agar Saboraud. FITCconjugated TEL, but not LLP, was able to link macroconidia and arthosporated forms of M. canis, as it was shown by fluorescent microscopy. These results suggested that inhibitory effects of LLP on M. canis growth may be related to lectin interaction with carbohydrates present in microorganism surface, mainly GIcNAc.