Immunological profile of mice immunized with a polyvalent virosome-based influenza vaccine.

BACKGROUND: Influenza A virus (IAV) causes respiratory disease in pigs and is a major concern for public health. Vaccination of pigs is the most successful measure to mitigate the impact of the disease in the herds. Influenza-based virosome is an effective immunomodulating carrier that replicates the natural antigen presentation pathway and has tolerability profile due to their purity and biocompatibility. METHODS: This study aimed to develop a polyvalent virosome influenza vaccine containing the hemagglutinin and neuraminidase proteins derived from the swine IAVs (swIAVs) H1N1, H1N2 and H3N2 subtypes, and to investigate its effectiveness in mice as a potential vaccine for swine. Mice were immunized with two vaccine doses (1 and 15 days), intramuscularly and intranasally. At 21 days and eight months later after the second vaccine dose, mice were euthanized. The humoral and cellular immune responses in mice vaccinated intranasally or intramuscularly with a polyvalent influenza virosomal vaccine were investigated. RESULTS: Only intramuscular vaccination induced high hemagglutination inhibition (HI) titers. Seroconversion and seroprotection (> 4-fold rise in HI antibody titers, reaching a titer of ≥ 1:40) were achieved in 80% of mice (intramuscularly vaccinated group) at 21 days after booster immunization. Virus-neutralizing antibody titers against IAV were detected at 8 months after vaccination, indicating long-lasting immunity. Overall, mice immunized with the virosome displayed greater ability for B, effector-T and memory-T cells from the spleen to respond to H1N1, H1N2 and H3N2 antigens. CONCLUSIONS: All findings showed an efficient immune response against IAVs in mice vaccinated with a polyvalent virosome-based influenza vaccine.

On the influence of the source of porcine colostrum in the development of early immune ontogeny in piglets.

The effects on the ontogeny of serum cytokines and immune cells caused by feeding suckling piglets with sow/gilt colostrum and milk replacer was assessed in the present study. After farrowing, the piglets born were randomized into six groups: GG and SS (n = 10/group): piglets were kept with their dam; GS (n = 10): piglets were changed from gilts to sows; SG (n = 10): piglets were changed from sows to gilts; GMR (n = 6) and SMR (n = 8): piglets from either gilts or sows were isolated from the dams and were bottle-fed ad libitum with commercial formula milk replacer. The piglets remained in the groups during the first 24 h of life and were later returned to their respective mothers. Serum immunoglobulin concentration and lymphocyte proliferation from the blood, spleen, thymus, and mesenteric lymph node of the piglets were assessed at 24 h and at 28 days of age. Serum cytokine concentrations were measured through a cytokine multiplex assay at 24 h. Overall, piglets suckling on sows (SS and GS) had a higher concentration of serum immunoglobulin at 24 h, which was also associated with a rise in plasma cytokine concentration and greater ability of B and T cells from lymphatic organs and blood mononuclear cells to respond to mitogens. We suggest a bias towards Th1-, Th2-, and Th17-cell polarizing and cytokines during the suckling period, which may be influenced by maternal immunological factors in the colostrum, such as dam parity. All findings suggest sow parity having a possible role, which may contribute to exerting a modulating action on immune response development.

Toltrazuril-Loaded Polymeric Nanocapsules as a Promising Approach for the Preventive Control of Coccidiosis in Poultry.

Coccidiosis is a disease caused by intracellular protozoan parasites of the genus Eimeria that affect the intestinal tract of poultry. However, strain resistance and drug residue in the carcass have drawn the attention of the productive sector. The nanotechnology can improve the biological effect of drugs, reducing of administered doses and toxic effects. Due to this, toltrazuril-load polymeric nanoparticles based on Eudragit® S100 (NCt) or poly-ε-caprolactone (LNCt) were developed to prevent coccidiosis in broilers. Nanoformulations were produced and showed homogeneous particle diameter distribution in the nanometer range (z-average and D (4.3) < 200 nm), negative zeta potential (<-8.93 mV), drug content ~100%, and encapsulation efficiency >90%. Cell viability assays using avian fibroblasts showed that LNCt presented no relevant toxicity up to 72 h. LNCt was then prophylactically administrated to chicken followed by challenge with Eimeria oocysts. The evaluation of the small intestine and cecum showed that the treatment with LNCt (3.5 mg/kg/day) in drinking water reduced the lesion scores and oocysts excretion, similar to the reference medicine containing toltrazuril (Baycox®, 7 mg/kg/day). The current study shows the potential protective use of nanoencapsulating anticoccidial drugs as a promising approach for the control of coccidiosis in poultry.

Comparative study of egg contamination with SalmonellaHeidelberg and Salmonella Typhimurium / Estudo comparativo da contaminação de ovos com SalmonellaHeidelberg e Salmonella Typhimurium

Cases of salmonellosis in humans have been associated with consumption of eggs contaminated with this bacterial pathogen due to insufficient heat treatment. The most prevalent serotypes of Salmonella in Brazil include serotypes Enteritidis, Typhimurium, and Heidelberg. The first two serotypes are major causes for eggs to be withheld from sale and for recalls over Salmonella contamination concerns in both domestic and foreign markets. Eggs may be contaminated through transovarian infection (transovarial transmission) due to the presence of the microorganism in the hen's oviduct and bacterial penetration of the eggshell. There is little data in the literature on the susceptibility of egg contamination and eggshell penetration by Brazilian serotypes of Salmonella. The present study aimed to evaluate the ability of S. Heidelberg and S. Typhimurium serotypes to penetrate through the eggshell and detect these bacteria in the albumen and yolk according to the thickness of the eggshell. SPF (specific-pathogen-free) eggs were artificially contaminated by contact with moist cotton containing Salmonella (15 x 108 CFU/ml). Eggs were divided into the following groups: negative control (not contaminated), S. Heidelberg, and S. Typhimurium. Subsequently, these eggs were incubated at 37°C, and their contents analyzed after 4 h and 24 h of incubation. The evaluation (assessment) of the contamination was performed by traditional bacteriology and confirmed by biochemical and serological tests. Treatments were compared with Fisher's test using a SAS statistical software. For S. Heidelberg, the percentage of positivity (positive cases) was lower in both albumen and yolk at 4 h and 24 h intervals (33.33% and 3.7%, and 3.7% and 3.7%, respectively) compared to S. Typhimurium (26.63% and 7.41%, and 33.33% and 33.33%, respectively). These findings suggest that the former strain (S. Heidelberg) was unable to survive in the hostile environment of the albumen. In contrast, eggshell thickness had no significant correlation with the number of positive samples. In conclusion, the results obtained in the egg infection model show that the Salmonella strains tested were able to penetrate the eggshell and multiply in both the albumen and yolk and that S. Typhimurium proved to be the most efficient to grow within these portions of the egg.(AU)

Salmonelose em humanos é frequentemente associada ao consumo de ovos contaminados sem o devido processamento térmico. No Brasil, os sorotipos mais prevalentes são: Enteritidis, Typhimurium e Heidelberg, alvo de barreiras sanitárias na comercialização de ovos. O ovo pode ser contaminado por via transovariana, pela presença da bactéria no oviduto da ave e também por penetração da bactéria através da casca do ovo. Existem poucas informações acerca da capacidade de contaminação no ovo por sorotipos isolados no Brasil. Este estudo teve como objetivo avaliar a capacidade dos sorotipos S. Heidelberg e S. Typhimurium penetrar através da casca do ovo e colonizar a albumina e gema, relacionando à espessura da casca. Os ovos SPF (livres de patógenos específicos) foram contaminados artificialmente pelo contato com algodão umedecido (15 x 108 CF/mL). Os ovos foram divididos nos seguintes grupos: controle negativo (sem contaminação), S. Heidelberg e S. Typhimurium. Posteriormente foram incubadas a 37°C e seu conteúdo foi analisado após 4 e 24 h. A avaliação da contaminação foi realizada por bacteriologia tradicional e confirmada por testes bioquímicos e sorológicos. Os tratamentos foram comparados com o teste de Fisher usando o software estatístico SAS. Para S. Heidelberg, a percentagem de positividade foi menor no albúmen e gema às 4 e 24 h (33,33% e 3,7%, 3,7% e 3,7%, respectivamente) em comparação com S. Typhimurium (26,63% e 7,41%, 33,33% e 33,33%, respectivamente), sugerindo que a primeira estirpe foi mais vulnerável as condições hostis da albumina. Por outro lado, a espessura da casca do ovo não teve relação significativa com a positividade das amostras. Em conclusão, o modelo de infecção do ovo mostrou que as cepas foram capazes de penetrar a casca do ovo e sobreviver na albumina e gema, sendo que o sorotipo S. Typhimurium foi mais eficiente.(AU)