Browsing by Autor "Alfredo De Ioannes"

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Novel hemocyanin from the Fissurella latimarginata exhibits an outstanding immunogenicity and non-specific immunomodulatory effects in a melanoma model (53.6)
(American Association of Immunologists, 2012) Marı́a Inés Becker; Sergio Arancibia; Espinoza Cecilia; Fabián Salazar; Miguel Del Campo; Raimundo Born; Jorge Ferreira; Augusto Manubens; Alfredo De Ioannes
Abstract The versatile properties of mollusk hemocyanins in biomedical applications, including non-specific immunostimulant during the therapy of bladder cancer and carrier/adjuvant in cutting-edge therapeutic cancer vaccines, has increased the interest in finding new hemocyanins with better immunomodulatory properties. Here, we evaluate the physicochemical and immunological properties of the hemocyanin from Fissurella latimarginata (FLH). This protein shares with keyhole limpet hemocyanin (KLH) and Concholepas hemocyanin (CCH) the typical hollow cylinder structure and it is also made by two subunits (~350 KDa). ConA lectin staining of FLH, demonstrated the presence of mannosylated carbohydrate structures as well as in KLH and CCH. The humoral responses in mice demonstrated that antibody titers induced by FLH itself were significantly higher than KLH and CCH. However, it performance as a carrier protein to induce antibodies to the hapten DNFB, was similar to the other carriers using Freund’s adjuvant as a repository. More interestingly, FLH exhibits an outstanding antitumor activity prolonging mice survival, when was evaluated and compared with KLH and CCH in the B16F10 mouse melanoma model. In addition, flow cytometry analysis showed that FLH induced a significant number of tumor-infiltrating CD4+ cells and also, IFN-δ secretion. Together, these findings introduce a novel hemocyanin, with intrinsically more immunogenic and immunomodulatory capacities for antitumor therapy.
Proteolytic activity of rabbit perivitelline spermatozoa
(Cambridge University Press, 1999) Manuel M. Valdivia; T. Sillerico; Alfredo De Ioannes; C. Barros
Acrosin, an acrosomal serine protease, has been associated with binding of spermatozoa and their penetration through the zona pellucida. This study was aimed at determining whether the remaining proacrosin/acrosin system on rabbit perivitelline spermatozoa still has proteolytic activity and whether this activity is involved in further penetration of unfertilised rabbit eggs. Eight hundred and sixty-five rabbit perivitelline spermatozoa were evaluated by the gelatin-substrate film technique for the detection of acrosin on individual spermatozoan. Fifteen per cent of the studied spermatozoa showed small digestion halos on the gelatin film. The proteolytic activity of rabbit perivitelline spermatozoa was inhibited in the presence of 1 mg/ml of soybean trypsin inhibitor (SBTI) or with 20 micrograms/ml of a mixture of the monoclonal anti-proacrosin/acrosin antibody. In vitro fertilisation occurred in 21.8% of rabbit oocytes co-incubated with perivitelline spermatozoa and was completely inhibited when oocytes were incubated with 600 micrograms/ml of a mixture of three anti-acrosin monoclonal antibodies (ACRO-A8C10, ACRO-C2B10 and ACRO-C5F10). Inseminations in the presence of anti-cholera monoclonal antibody (irrelevant to spermatozoa) resulted in 17.6% fertilisation. These results support the idea that the residual proacrosin/acrosin system in perivitelline spermatozoa might be involved in spermatozoal binding and/or second penetration through the zona pellucida.