Browsing by Autor "Sergio Arancibia"

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Copper nanoparticles suppresses nitric oxide production in macrophages (CAM5P.234)
(American Association of Immunologists, 2014) Sergio Arancibia; Andrea Barrientos
Abstract Copper and copper oxide nanoparticles (CuNP) have been utilized as anti-microbial agent, metal catalyst, diet supplement, high thermal conductive material, lubricant additive, among others. Although the uses of CuNP are relatively new, there is an increasing interest to know their immunotoxicology. CuNP have shown to induce one of the most potent acute inflammatory reactions among several types of nanoparticles. Recently, in a pulmonary infection model, it was demonstrated that mice, which had been previously exposed to CuNP, presented an impaired bacterial clearance. These effects were due to a reduction in macrophage function; however, the precise molecular mechanism underlying these effects is still unknown. Here, we described the effects of CuNP in the response of peritoneal macrophages against microbial products. Transmission electron microscopy (TEM) data showed that CuNP were rapidly internalized by macrophages. The internalization of the particles induced a significant reduction of cell viability in comparison with other nanoparticles. The challenge with CuNP inhibited LPS-mediated nitric oxide (NO) production in a dose dependent manner. These results showed that CuNP modulate the expression of a key inflammatory mediator that is crucial to eliminate bacterial infection.
Hemocyanins in the Immunotherapy of Superficial Bladder Cancer
(2012) Sergio Arancibia; Fabián Salazar; Mara Ins
Chemoand immunotherapeutic approaches have been used to prevent recurrence of transitional cell carcinoma (TCC), the most common type of superficial bladder cancer (SBC). The bacillus Calmette-Guerin (BCG) vaccine for tuberculosis, which consists of an attenuated form of Mycobacterium bovis, is the most commonly used immunotherapeutic agent (Morales et al., 1976). Despite the successful results achieved with BCG, its serious side effects have led researchers to investigate other immunostimulatory substances. In the early 1970s, Olsson and collaborators reported that subcutaneous stimulation with keyhole limpet hemocyanin (KLH) from the Californian marine gastropod Megathura crenulata significantly reduced SBC recurrence frequency in TCC patients without any toxic side effects, making it ideal for long-term repetitive treatments (Olsson et al., 1974). These results provided promising support for the use of mollusk hemocyanins as alternative agents in SBC immunotherapy. Hemocyanins, blue respiratory glycoproteins that were discovered in 1878 by Leon Fredericq (Ghiretti-Magaldi & Ghiretti, 1992), are found freely dissolved in the blood of some mollusks and arthropods. These proteins are giant structures with molecular weights between 4 and 8 MDa, and they exhibit some of the most complex and sophisticated quaternary structures known. Hemocyanins are part of the type-3 group of copper proteins that includes phenoloxidases and tyrosinases (Decker & Tuczek, 2000). These proteins contain active copper-containing sites in which the Cu(I,I) state is oxidized to the Cu(II,II) state, thus accounting for their distinctive deep blue color. Because of these properties, the biochemistry of hemocyanins has been intensively studied (van Holde & Miller, 1995). The pioneering work of Weigle in the 1960s on the immunochemical properties of KLH demonstrated its remarkable immunostimulatory properties in an experimental animal model (Weigle, 1964). These results were quickly incorporated into clinical studies to evaluate its immunological effects. Because the primary amino acid sequences of mollusk hemocyanins are highly divergent from mammalian sequences, they are strongly recognized by the immune system, resulting in potent immunogenicity; these proteins can be used therapeutically as non-specific immunostimulants with beneficial clinical outcomes. Moreover, hemocyanins have been extensively used as carriers to generate antibodies against diverse hapten molecules and
Hemocyanins Stimulate Innate Immunity by Inducing Different Temporal Patterns of Proinflammatory Cytokine Expression in Macrophages
(American Association of Immunologists, 2016) Ta-Ying Zhong; Sergio Arancibia; Raimundo Born; Robert Tampé; Javiera Villar; Miguel Del Campo; Augusto Manubens; Marı́a Inés Becker
Hemocyanins induce a potent Th1-dominant immune response with beneficial clinical outcomes when used as a carrier/adjuvant in vaccines and nonspecific immunostimulant in cancer. However, the mechanisms by which hemocyanins trigger innate immune responses, leading to beneficial adaptive immune responses, are unknown. This response is triggered by a proinflammatory signal from various components, of which macrophages are an essential part. To understand how these proteins influence macrophage response, we investigated the effects of mollusks hemocyanins with varying structural and immunological properties, including hemocyanins from Concholepas concholepas, Fissurella latimarginata, and Megathura crenulata (keyhole limpet hemocyanin), on cultures of peritoneal macrophages. Hemocyanins were phagocytosed and slowly processed. Analysis of this process showed differential gene expression along with protein levels of proinflammatory markers, including IL-1β, IL-6, IL-12p40, and TNF-α. An extended expression analysis of 84 cytokines during a 24-h period showed a robust proinflammatory response for F. latimarginata hemocyanin in comparison with keyhole limpet hemocyanin and C. concholepas hemocyanin, which was characterized by an increase in the transcript levels of M1 cytokines involved in leukocyte recruitment. These cytokine genes included chemokines (Cxcl1, Cxcl3, Cxcl5, Ccl2, and Ccl3), ILs (Il1b and Ifng), growth factors (Csf2 and Csf3), and TNF family members (Cd40lg). The protein levels of certain cytokines were increased. However, every hemocyanin maintains downregulated key M2 cytokine genes, including Il4 and Il5 Collectively, our data demonstrate that hemocyanins are able to trigger the release of proinflammatory factors with different patterns of cytokine expression, suggesting differential signaling pathways and transcriptional network mechanisms that lead to the activation of M1-polarized macrophages.
Macrophages stimulated with mollusk hemocyanins present a different expression pattern of proinflammatory cytokines and chemokines (VAC3P.956)
(American Association of Immunologists, 2014) Marı́a Inés Becker; Ta-Ying Zhong; Sergio Arancibia; Raimundo Born; Robert Tampé; Miguel Del Campo; Augusto Manubens
Abstract Hemocyanins inoculated in mammals induce a Th1-dominant response with beneficial clinical outcomes, being used as carrier/adjuvant in vaccines and as immunostimulant for the treatment of bladder cancer. However, its effects during the early phases of the immune response are unknown. We hypothesized that when hemocyanins are incorporated by antigen presenting cells, they induce an inflammatory milieu, producing a bystander effect, key event in its non-specific immunostimulatory effects. Here, in vitro cultures of murine peritoneal macrophages were incubated with different hemocyanins from M. crenulata (KLH) or C. concholepas (CCH) or F. latimarginata (FLH), to study the correlation between mRNA and protein levels from a panel of proinflammatory cytokines and chemokines, using qPCR and ELISA. The results showed that hemocyanins were endocyted and slowly processed by macrophages, stimulating the expression of IL-6, IL-12p40 and TNF-α at different times and intensities. FLH and KLH but not CCH at 24 h, induced an increased in the expression of chemokines related to leukocyte extravasations, such as CCL-3, CXCL-1 and CXCL-5. Moreover, hemocyanins kept down-regulated key Th2 cytokines such as IL-4 and TGF-β2. We concluded that each hemocyanin can stimulate different kinetic patterns of proinflammatory cytokines and chemokines expression in macrophages, suggesting different signaling pathways, which can be explained in part, by its structural differences.
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.