Examinando por Autor "Tafalla, Carolina"

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Bacillus subtilis supplemented feeding as a method to increase IgM titers and affinity in response to fish vaccination.
(Elsevier, 2025-07) Vicente-Gil, Samuel; Simón, Rocío; Nogales-Mérida, Silvia; Nuñez-Ortiz, Noelia; Fouz, Belén; Serra, Claudia; Ordás, M. Camino; Abós, Beatriz; Herranz-Jusdado, Juan Germán; Morel, Esther; Díaz-Rosales, Patricia; Tafalla, Carolina
In aquaculture, the use of probiotics in supplemented diets has been shown to be a suitable strategy to increase the immune status of fish and thereby reduce the impact of pathogens. Specifically, the immunostimulatory effects of the probiotic microorganism Bacillus subtilis have been widely confirmed both in vitro and in vivo in many aquacultured species. However, whether feeding fish with probiotic-enriched diets affects the adaptive immune response mounted to a vaccine has been scarcely addressed in fish. Therefore, in this study, we addressed this using rainbow trout (Oncorhynchus mykiss) as a model. To this aim, fish were fed a probioticsupplemented diet or a control diet for 30 days and thereafter immunized through different administration routes with different antigenic models, including 2,4,6-trinitrophenyl lipopolysaccharide (TNP-LPS), a Yersinia ruckeri bacterin or a DNA vaccine against viral haemorrhagic septicaemia virus (VHSV). The effects of the B. subtilis-supplemented diet on the systemic specific IgM responses mounted were then established. For TNPLPS, we also determined the effects of the diet on antibody affinity using a BIAcore instrument, which allows direct detection of antibody-antigen interactions by surface plasmon resonance (SPR) changes. The results presented reveal beneficial effects of feeding this probiotic on the vaccine-induced antibody response and point to the usefulness of designing holistic vaccination protocols that not only focus on antigen optimization or administration regimes, but also include diet composition as an important factor to influence the outcome of the immunization strategy.
Effect of β-glucans on rainbow trout (Oncorhynchus mykiss) IgM+ B cells
(Elsevier, 2024-08) Martín, Diana; Ordás, M. Camino; Morel, Esther; Nuñez- Ortiz, Noelia; Díaz- Rosales, Patricia; Vicente- Gil, Samuel; Zarza, Carlos; Jensen, Linda; Tafalla, Carolina
β-glucans are carbohydrates present in the cell wall of many fungi, which are often used as immunostimulants in feeds for farmed species. Their capacity to activate innate immune responses directly acting on innate cell populations has been widely documented in fish. However, whether they can affect the functionality of adaptive immune cells has been scarcely explored. In this context, in the current work, we have determined the effects of β-glucans on rainbow trout blood IgM+ B cells in the presence or absence of 2,4,6-trinitrophenyl hapten conjugated to lipopolysaccharide (TNP-LPS), a model antigen. For this, rainbow trout peripheral blood leukocytes were incubated with different doses of β-glucans or media alone in the presence or absence of TNP-LPS for 48 h. The size, levels of expression of surface MHC II, antigen processing and phagocytic capacities and proliferation of IgM+ B cells were then studied by flow cytometry. The number of IgM-secreting cells in the cultures was also estimated by ELISpot. β-glucans significantly decreased the levels of surface MHC II expression and the antigen processing capacities of these cells, especially in the presence of TNP-LPS, while they increased their phagocytic activity. On their own, β-glucans slightly activated the proliferation of IgM+ B cells but reduced that induced by TNP-LPS. In contrast, β-glucans significantly increased the number of cells secreting IgM in the cultures. This effect of β-glucans on the IgM-secreting capacity of B cells was also confirmed through a feeding experiment, in which the IgM-secreting capacity of blood leukocytes obtained from fish fed a β-glucan-supplemented diet for one month was compared to that of leukocytes obtained from fish fed a control diet. Altogether, these findings contribute to increase our knowledge regarding the effects of β-glucans on fish adaptive responses.
Immunological characterization of the rainbow trout bursa
(Elsevier, 2025) Abós, Beatriz; Morel, Esther; Fernández-del Ama, Laura; Ordás, M. Camino; Vicente-Gil, Samuel; Carrasco, Juan Carlos; Koppang, Erling; Tafalla, Carolina; Herranz-Jusdado, Juan Germán
The bursa of Fabricius is an immune organ, located in the caudo-dorsal surface of the cloaca, responsible for the development and maturation of avian B cells. A few years ago, a lymphoepithelial tissue placed caudal to the urogenital papilla of the cloaca analogous to the bursa was identified for the first time in Atlantic salmon (Salmo salar). The salmon bursa was demonstrated to involute around sexual maturation, as in birds. However, no primary lymphoid functions were identified in this tissue. In the current study, we have identified a homologous immune organ in rainbow trout (Oncorhynchus mykiss), a different salmonid species. This lymphoepithelium covering a blind sac, caudal to the anus, was identified in rainbow trout at different stages of development and it also experienced regression in an age-dependent way. It contained abundant IgM+ B cells and CD3+ cells and especially numerous was the number of MHC II-expressing cells. In contrast to Atlantic salmon, in rainbow trout, the bursa epithelium contained quite a few IgT+ B cells but very few IgD+ B cells. Thus, by flow cytometry, we could determine that the IgM+ B cells identified in the trout bursa had lost surface IgD expression. Interestingly, although an immunization of rainbow trout by bath barely had effects on the bursa at a transcriptional level, when fish were immunized anally with a model antigen, there were significant changes in the levels of transcription of immune genes in this tissue. These included secreted igm, secreted and membrane igd, bcma and prdm1-a2. Altogether these results evidence the existence of a bursa-like immune structure in another teleost species and provide novel information to understand the immune role of this tissue in fish, pointing to a relation to gut immune responses.
The oral delivery of Bacillus subtilis spores modulates skin and intestinal mucus responses in rainbow trout (Oncorhynchus mykiss).
(Elsevier, 2024-08) Vicente- Gil, Samuel; Nogales-Mérida, Silvia; Gonçalves, Gabriela; Serra, Claudia R; Ordás, M. Camino; Tafalla, Carolina; Díaz- Rosales, Patricia
Bacillus subtilis is a spore-forming microorganism, recognized as a safe probiotic strain. Its endospores are easily produced at a large scale, can be dehydrated and maintain their characteristics after long-term storage, providing great advantages for their application in aquafeeds. Nonetheless, knowledge on the effects that B. subtilis provokes on fish mucosal immunity is still scarce. In this context, the aim of this work was to explore the effects of the oral administration of B. subtilis spores to rainbow trout (Oncorhynchus mykiss) for 30 days on the intestinal and skin mucus, focusing on a range of immune and enzymatic parameters. Thus, fish supplemented with B. subtilis spores showed increased levels of total immunoglobulin (Ig) in intestinal and skin mucus, as well as IgM levels in both mucus and serum. B. subtilis spores induced an increase of peroxidase activities in mucus from both sources. Although superoxide dismutase (SOD) activity was not affected by the spores, NO production significantly decreased in skin mucus. Finally, the bactericidal activity of the intestinal and skin mucus was significantly higher in fish fed the probiotic spores. The results obtained demonstrate that the dietary supplementation with B. subtilis spores enhances mucosal defense mechanisms by increasing immunological parameters of the intestinal and skin mucus.