No abstract

No abstract

Bovine herpesvirus type 1 (BoHV-1) is recognized as a major cause of respiratory, reproductive disease and abortion in cattle. Vaccination is widely applied to minimize losses induced by BoHV-1 infections; however, vaccination of dams during pregnancy with modified live virus (MLV) vaccines has been occasionally associated to abortions. We have previously reported the development of a BoHV-1 recombinant virus, constructed with basis on a Brazilian BoHV-1 (Franco et al. 2002a) from which the gene coding for glycoprotein E (gE) was deleted (gE-) by genetic manipulation. Such recombinant has been previously evaluated in its potential as a differential vaccine (gE- vaccine) that allows differentiation between vaccinated and infected animals. Here, in the first part of the present study, the safety of the gE- vaccine during pregnancy was evaluated by the intramuscular inoculation of 10(7.4) tissue culture 50 % infective doses (TCID50) of the virus into 22 pregnant dams (14 BoHV-1 seronegative; 8 seropositive), at different stages of gestation. Other 15 pregnant dams were kept as non-vaccinated controls. No abortions, stillbirths or fetal abnormalities were seen after vaccination. Seroconversion was observed in both groups of previously seronegative vaccinated animals. In the second part of the study, the potential of the gE- vaccine virus to spread among beef cattle under field conditions was examined. Four heifers were inoculated intranasally with a larger amount (10(7,6) TCID50) of the gE- vaccine (to increase chances of transmission) and mixed with other sixteen animals at the same age and body condition, in the same grazing area, at a population density equal to the average cattle farming density within the region (one cattle head per 10,000 m²), for 180 days. All animals were monitored daily for clinical signs. Serum samples were collected on days 0, 30, 60 and 180 post-vaccination. Seroconversion was observed only in vaccinated heifers. These results indicate that, under the conditions of the present study, the gE- vaccine virus did not cause any noticeable harmful effect on pregnant dams and on its offspring and did not spread horizontally among cattle.

Disrupted coordination of angiogenesis regulating signals, among them the vascular endothelial growth factor (VEGF) and angiopoietins (Angs), has been associated with abnormal angiogenesis and tumor progression. While VEGF induces endothelial cell proliferation, thereby initiating vessel formation, Angs are subsequently required for mural cell attachment, thus influencing remodeling and maturation of this vasculature. In addition to tumor cell, endothelial and mural cells, as well as myofibroblasts may also contribute to the secretion of these factors. In this study, we have analyzed by immunohistochemistry the expression of VEGF, Ang-1, Ang-2 and the Angs receptor Tie2 in both the stroma and tumor cells of mucoepidermoid carcinoma (MEC) of salivary gland. We have demonstrated that when myofibroblasts were detected adjacent to the cancer cells, they were frequently associated with intense positive staining for Ang-1 and Ang-2, and no reactivity to VEGF and Tie2. These myofibroblast-rich Ang-1 and Ang-2-stained areas were more commonly found in high-grade MEC cases than in low-grade ones. As for the malignant cells, they frequently expressed all proteins studied, but Ang-2 and VEGF were detected at higher levels compared to Ang-1 and Tie2. Our results indicate that the MEC environment favors cooperative activity between Angs and VEGF in modulating vascular growth and tumor aggressiveness.

Bovine herpesvirus type 5 (BHV-5) is the causative agent of bovine herpetic encephalitis, a major concern for cattle farming in Brazil and Argentina. We recently developed a differential, gE-negative vaccine (265 gE-), based on a Brazilian BHV-1 strain. The present study was carried out to examine whether such a vaccine would confer protection to BHV-5 infections. It was concluded that the recombinant BHV-1 vaccine tested here is not capable of conferring full protection to BHV-5 challenge.