Gloria Ramírez

Molecular and in vitro characterization of field isolates of bovine herpesvirus-1

Bovine Herpesvirus-1 (BoHV-1) is distributed worldwide and is a major pathogen in cattle, being the causal agent of a variety of clinical syndromes. The aim of this study was to isolate and to characterize (molecular and biological characterization) BoHV-1 from 29 immunosuppressed animals. It was possible to obtain 18 isolates, each from a different animal, such as from the respiratory and reproductive tracts. In some cases the cytopathic effect was visible 12 hours post-inoculation, and became characteristic after 36–48 hours. Biological characteristics were evaluated and compared with Iowa and Colorado-1 reference strains, and differences were found in plaque size, virus titer measured by TCID50 and PFU/mL, and one step virus curves. These results showed that some isolates had a highly virulent-like behavior in vitro, compared to the reference strains, with shorter eclipse periods, faster release of virus into the supernatants, and higher burst size and viral titer. There were no differences in glycoprotein expression of BoHV-1 isolates, measured by Western blot on monolayers. Moreover, using restriction endonucleases analysis, most of the viruses were confirmed as BoHV-1.1 and just one of them was confirmed as BoHV-1.2a subtype. These findings suggest that some wild-type BoHV-1 isolates could be useful as seeds to develop new monovalent vaccines.

Evaluación de la prueba ELISA usando una cepa de campo como antígeno, para detectar anticuerpos contra el virus de la Rinotraqueitis Bovina Infecciosa

Evaluation of ELISA test use of field strain (antigen) to detect antibodies against Infectious Bovine Rhinotracheitis virus. The following study set up an enzymatic immune test (ELISA) using viral particles broke up of field strain of IBR virus; it showed a high sensibility and specificity and low rate of false negatives and positives. Positive and negative bovine serum which ELISA technique was normalized, were analyzed by seroneutralization to determine anti IBR antibodies; It was collected positive and negative serum with titles 1:4 to 1:128 and was considered dilution of bovine serum 1:50 as optimal dilution to ELISA technique. On the other hand, coefficient of variation BR was used to analyze the rehearsing of absorbance obtained by positive and negative serum. The results obtained were less than 20%, which indicated an appropriate

Cultivos celulares como alternativa para el aislamiento y la producción de biológicos contra el Virus de Influenza

Influenza Virus has been recognized as an important pathogen in human and animal populations causing many respiratory diseases. Vaccine production and isolation of human and animal influenza viruses are made mainly in chicken embryo eggs, being the conventional method used for decades, however, several issues have been found for vaccine manufacture related with low efficiency of processes due to limited capacity of production (sometimes requiring one or two eggs to obtain a vaccine dose) and time spending that leads to decrease in the ability for fast vaccine production processes in a pandemic situation. The use of continuous cell lines for viral vaccine manufacture rises as a feasible choice offering several advantages including the opportunity to use fully characterized and standardized cells; in addition, cell-culture-derived vaccines don?t require further planning and vaccines can be produced rapidly. The aim of this paper is to know different alternatives employed in culture and isolation of influenza viruses, emphasizing in the use of cell culture as a substrate for isolation and manufacture of vaccines for use in humans and animals.