J. F. F. Bittar

Perfil fenotípico de linfócitos periféricos de bovinos de raças européias

The phenotypic profile of bovine lymphocytes was evaluated in 18 bovines (Bos taurus) from three different breeds, being nine Holstein, six Hereford, and three Brown Swiss. All animals were free from ticks and hemoparasites, as determined after jugular vein blood sampling. The immunophenotypes of peripheral lymphocytes were evaluated by flow cytometry. Peripheral lymphocytes were exposed to bovine fluorescein-labeled monoclonal antibodies including anti-CD4, anti-CD8, and anti-purified bovine CD21 specificities. After lysing the erythrocytes with a commercial lysing solution (FACSTM ), the lymphocytes were washed, fixed, and evaluated by flow cytometry. Significant differences in the phenotypic profiles of peripheral lymphocytes among all breeds were found. Holstein animals showed a lower percentage of total T lymphocytes (CD4 and CD8) and higher percentage of B lymphocytes (CD21). In addition, the lymphocytes from Holstein animals showed a lower T/B ratio than the lymphocytes from Hereford animals. These results suggest the existence of different phenotypic profiles of peripheral lymphocytes from European breeds of cattle. Such differences may be related to the different pattern of immune response described for these breeds in the literature and may account to varying disease resistance among breeds.

Influence of endogamy and mitochondrial DNA on immunological parameters in cattle

BackgroundEndogamy increases the risk of manifestation of deleterious recessive genes. Mitochondrial DNA allows the separation of American Zebu (Bos indicus and Bos taurus) and evaluate the effect of mitochondrial DNA on productive traits of cattle. However, the effect of endogamy and mitochondrial DNA (mtDNA) on the immune system remains unclear. The aim of this study was to evaluate the association between endogamy, mtDNA and immune parameters.ResultsA total of 86 cattle (43 cows and 43 calves) were used in this study. Age, endogamy, milk yield, and origin of mtDNA were measured and their influence on immunological parameters was evaluated. Older cows had increased CD4+ T cells, decreased CD21+ and γδhigh T cells as well as increased CD4+/CD8+ and T/B ratio. Multiple regression analysis indicated that endogamy in calves was associated with increased CD8+ T and CD21+ B lymphocytes, and decreased γδhigh T cells in peripheral blood. Cows with medium and lower endogamy had a lower percentage of B lymphocytes and γδlow T cells and cows with lower endogamy had higher levels of γδ T cells and γδhigh T cells, as well as the CD4+/CD48+ cell ratio. Calves with higher endogamy had higher levels of CD8+ T lymphocytes, whereas calves with lower endogamy had lower levels of γδlow T cells.ConclusionsThese results demonstrated for the first time that endogamy influences the immune system of cattle.

IgY-Technology Applied to Studies of Toxoplasma gondii Infection

In this chapter, we describe relevant aspects of immunoglobulin Y (IgY) technology for Toxoplasma gondii applications, including comparison of avian IgY antibody with mam‐ malian IgG antibody, egg yolk IgY production and isolation procedures, important applications for IgY antibody, and state of the art and perspectives for IgY‐technology in T. gondii studies. T. gondii is a worldwide public health problem. IgY‐technology pro‐ vides an alternative antibody (IgY) to mammalian Immunoglobulin G (IgG) antibody. IgY‐technology involves the chicken immunization, yolk IgY isolation, antibody charac‐ terization, and purified IgY application to several kinds of methods. Immunized chicken transfers a specific IgY from blood to egg yolk. Phylogenetic distance between chickens and mammals influences the generation of antibody repertoires recognizing an antigen profile. IgY is not bound to rheumatoid factor or mammalian complement protein and thus avoids the false‐positive results. Yolk IgY isolation is carried out by simple pro‐ cedures that are accessible for any laboratory and, also, for IgY isolation at large‐scale production. IgY‐technology provides antibodies for proteomic studies, diagnostic assays, and immunotherapy. Although IgY‐technology is promising, there is a reduced number of investigations with IgY and T. gondii. Future perspectives involve the use of IgY‐tech‐ nology for the screening of new T. gondii antigens for diagnostics, therapy, or vaccine, development of innovative techniques for toxoplasmosis diagnostics and may be an immunotherapy for toxoplasmosis.

Bovine Trypanosomiasis: Retrospective Investigation and Clinical Signs

Trypanosoma vivax is a protozoan that causes Bovine tripanosomiasys. Originally from Africa, the disease has become common in other countries. Bovine trypanosomiasis is a disease underdiagnosed in many parts of the world, including Brazil. The lack of knowledge regarding this protozoan is a factor that contributes to the rapid spread of the disease. Many losses are attributed to the disease, including death of animals. This study aimed to perform a retrospective investigation of cattle with T. vivax that had blood samples forwarded to Veterinary Hospital of Uberaba-Brazil by performing the Buffy coat technique. The collected data showed that in 285 suspected animals, that had samples submitted to Hospital Veterinário de Uberaba, 17.54% were positive. Separating in gender, females had 22.37% of positivity rate and males 2.13%, which is explained by the handling of the animals where handlers are able to see signs of the disease and decreased milk production, besides the use of the same needle for oxytocin application before milking that spreads the disease for many animals in a short period of time. The biggest prevalence among ages was seen in animals between 1 to 12 months (35% of positivity) and 12 to 24 months of age (61.64% of positivity), possibly because of the immune system development, younger animals do not have immunity to the disease. The breed that most showed positivity was Holstein dairy breed (100%). The opportune diagnosis of T. vivax is an important finding since the disease leads to large losses in cattle ranching and prejudices the economic system.