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Papers by Daniela Rodriguez

Veterinary Immunology and Immunopathology, 2009

Veterinary Immunology and Immunopathology, 2010

Veterinary Immunology and Immunopathology, 2010

Group A bovine rotavirus (BRV) is the major cause of acute viral gastroenteritis in neonatal calv... more Group A bovine rotavirus (BRV) is the major cause of acute viral gastroenteritis in neonatal calves worldwide. Due to the early susceptibility to the infection prevention strategies are based on the improvement of passive immunity levels through cow vaccination in the last third of gestation. The major capsid antigen (VP6) of BRV is the most immunogenic viral protein and it is highly conserved among group A BRV. In this work, VP6 protein from BRV C-486 strain (P[1]G6) was expressed in insect cells using the baculovirus expression vector system. Recombinant VP6 was used to immunize cows and vaccine's efficacy was assessed in a colostrum-deprived calf model of BRV infection and disease. Immune colostrum pool was generated using first and second milking of the immunized cows. Calves receiving one dose of immune colostrum within the first 6h of life, or colostrum-deprived calves were orally inoculated with virulent BRV at 2 days of age. The animals were monitored for diarrhea, virus shedding and isotype-specific antibodies responses to BRV in both feces and serum. Calves receiving VP6-immune colostrum showed a reduction of both diarrhea and virus shedding (in terms of viral titer and excretion period) in comparison with the colostrum-deprived calves.

Vaccine, 2010

Infectious Bovine Rhinothracheitis (IBR) caused by bovine herpesvirus 1 (BoHV-1) infection is dis... more Infectious Bovine Rhinothracheitis (IBR) caused by bovine herpesvirus 1 (BoHV-1) infection is distributed worldwide. BoHV-1 either alone or in association with other respiratory cattle pathogens causes significant economic losses to the livestock industry. The aim of this work was to validate a guinea pig model as an alternative method to the current BoHV-1 vaccine potency testing in calves. Guinea pigs were immunized with two doses of vaccine, 21 days apart and sampled at 30 days post vaccination (dpv). BoHV-1 antibody (Ab) response to vaccination in guinea pigs, measured by ELISA and virus neutralization (VN), was statistically compared to the Ab response in cattle. The guinea pig model showed a dose-response relationship to the BoVH-1 antigen concentration in the vaccine and it was able to discriminate among vaccines containing 1 log 10 difference in its BoHV-1 concentration with very good repeatability and reproducibility (CV ≤ 20%). A regression analysis of the Ab titers obtained in guinea pigs and bovines at 30 and 60 dpv, respectively, allowed us to classify vaccines in three potency categories: "very satisfactory", "satisfactory" and "unsatisfactory". Bovines immunized with vaccines corresponding to each of these three categories were experimentally challenged with BoVH-1 virus, the level of protection, as measured by reduction of virus shedding and disease severity, correlated well with the vaccine category used. Data generated by 85 experiments, which included vaccination of calves and guinea pigs with 18 reference vaccines of known potency, 8 placebos and 18 commercial vaccines, was subjected to statistical analysis. Concordance analysis indicated almost perfect agreement between the model and the target species for Ab titers measured by ELISA and almost perfect to substantial agreement when Ab titers were measured by VN. Taken together these results indicate that the developed guinea pig model represents a novel and reliable tool to estimate batch-to-batch vaccine potency and to predict efficacy of killed BoHV-1 veterinary vaccines.

Journal of Virological Methods, 2009

Bovine Viral Diarrhea Virus (BVDV) is the causative agent of a worldwide disease. The virus infec... more Bovine Viral Diarrhea Virus (BVDV) is the causative agent of a worldwide disease. The virus infects bovines of all ages, causing reproductive problems and contaminating biological products of high commercial value. The large-scale production of BVDV vaccines presents the challenge of processing antigenic proteins that are highly susceptible to the processing environment. Potency testing requires the immunization of cattle in order to determine the neutralizing antibodies titers induced by the vaccine. An alternative to the in vivo test is an in vitro measurement of key viral antigens. This paper describes the development and validation of a sandwich-type indirect ELISA that is able to detect and quantify BVDV E2 glycoprotein in live and inactivated BVDV. Validation parameters such as repeatability, intermediate precision, and reproducibility indicated that the developed ELISA constitutes an advanced tool for evaluating the BVDV antigen throughout manufacturing and vaccine release testing.

Journal of Virological Methods, 2010

Two ELISAs to quantify antibodies to BoHV-1 in the sera of cattle and immunized guinea pigs were ... more Two ELISAs to quantify antibodies to BoHV-1 in the sera of cattle and immunized guinea pigs were developed and validated using ISO/IEC 17025 standards. The cut-off value of the assay was established at 20% positivity of a high positive control for screening of cattle. Using this threshold, the assay properly classified the OIE bovine reference sera EU1, EU2 and EU3. For vaccine potency testing, a cut-off of 40% was selected for both species. The reliability of the assays, given by their diagnostic sensitivity and specificity, using the threshold of 40% was 89.7% and 100%, respectively, for bovines and 94.9% and 100% for guinea pigs, respectively. There was almost perfect agreement between the ELISA and virus neutralization results. In addition, after vaccination, there was a good correlation between the neutralizing and ELISA antibody titers of the serum from the same bovine or guinea pig, sampled at 60 and 30 days post-vaccination, respectively (R(bovine)=0.88, R(guinea pig)=0.92; p<0.0001). A similar correlation was observed when analyzing the mean antibody titers of groups of vaccinated animals (R(bovine)=0.95 and R(guinea pig)=0.97; p<0.0001), indicating the relevance of the ELISAs for batch to batch vaccine potency testing in the target species and in the laboratory animal model. The intermediate precision of the assays expressed as the relative coefficient of variation (CV) of the positive control assayed over a 3-year period in the same laboratory was 22.2% for bovines and 23.1% for guinea pigs. The reproducibility of both techniques obtained in inter-laboratory assays was CV=12.4% for bovines and CV approximately 0 for guinea pigs, which met the requirements of the OIE…

Veterinary microbiology, Jan 17, 2011

Bovine Group A Rotavirus (RVA) is one of the main causes of neonatal calf diarrhea worldwide. The... more Bovine Group A Rotavirus (RVA) is one of the main causes of neonatal calf diarrhea worldwide. The present study reports the genotyping of bovine RVA strains circulating in Argentinean cattle from 2004 to 2010. Additionally, a new set of typing primers was designed and tested to differentiate between G8 and G6 (lineage III and IV) RVA strains. Bovine RVA was detected in 30% (435/1462) of the tested samples, corresponding to 49% (207/423) of the studied outbreaks with a similar detection rates in beef (53%; 67/127) and dairy herds (52%; 65/126). The RVA strains circulating in Argentinean cattle belonged to the common bovine genotypes G6 (lineages III and IV), G8, G10, P[5] and P[11]. A different RVA G/P-genotype distribution was found between the exploitation types, with the combination G6(IV)P[5] being by fare the most prevalent RVA strain in beef herds (58%), whereas a more even distribution of G6(III)P[11] (15%), G10P[11] (17%), G6(IV)P[5] (14%), and G6(IV)P[11] (6%) RVA strains wa...

Albéitar: publicación …, 2011

Información del artículo Diarrea neonatal del ternero.

Veterinary Immunology and Immunopathology, 2009

Our results demonstrate that immunization with LAM is able to induce a specific humoral immune re... more Our results demonstrate that immunization with LAM is able to induce a specific humoral immune response without interfering with IDR test usually used for bovine Tuberculosis diagnosis. It has been described that IgG1 is the predominant isotype in the immune response to LAM of infected animals Koets et al. (2001). Our results indicate that the same isotype profile is obtained when LAM is inoculated as a purified antigen. These results could support further investigations evaluating LAM as a candidate for a Paratuberculosis subunit vaccine.

Revista Argentina de Microbiología, 2014

Vaccine, Jan 16, 2010

Infectious Bovine Rhinothracheitis (IBR) caused by bovine herpesvirus 1 (BoHV-1) infection is dis... more Infectious Bovine Rhinothracheitis (IBR) caused by bovine herpesvirus 1 (BoHV-1) infection is distributed worldwide. BoHV-1 either alone or in association with other respiratory cattle pathogens causes significant economic losses to the livestock industry. The aim of this work was to validate a guinea pig model as an alternative method to the current BoHV-1 vaccine potency testing in calves. Guinea pigs were immunized with two doses of vaccine, 21 days apart and sampled at 30 days post vaccination (dpv). BoHV-1 antibody (Ab) response to vaccination in guinea pigs, measured by ELISA and virus neutralization (VN), was statistically compared to the Ab response in cattle. The guinea pig model showed a dose–response relationship to the BoVH-1 antigen concentration in the vaccine and it was able to discriminate among vaccines containing 1 log10 difference in its BoHV-1 concentration with very good repeatability and reproducibility (CV ≤ 20%). A regression analysis of the Ab titers obtaine...

Veterinary Immunology and Immunopathology, 2009

Veterinary Immunology and Immunopathology, 2010

Veterinary Immunology and Immunopathology, 2010

Group A bovine rotavirus (BRV) is the major cause of acute viral gastroenteritis in neonatal calv... more Group A bovine rotavirus (BRV) is the major cause of acute viral gastroenteritis in neonatal calves worldwide. Due to the early susceptibility to the infection prevention strategies are based on the improvement of passive immunity levels through cow vaccination in the last third of gestation. The major capsid antigen (VP6) of BRV is the most immunogenic viral protein and it is highly conserved among group A BRV. In this work, VP6 protein from BRV C-486 strain (P[1]G6) was expressed in insect cells using the baculovirus expression vector system. Recombinant VP6 was used to immunize cows and vaccine's efficacy was assessed in a colostrum-deprived calf model of BRV infection and disease. Immune colostrum pool was generated using first and second milking of the immunized cows. Calves receiving one dose of immune colostrum within the first 6h of life, or colostrum-deprived calves were orally inoculated with virulent BRV at 2 days of age. The animals were monitored for diarrhea, virus shedding and isotype-specific antibodies responses to BRV in both feces and serum. Calves receiving VP6-immune colostrum showed a reduction of both diarrhea and virus shedding (in terms of viral titer and excretion period) in comparison with the colostrum-deprived calves.

Vaccine, 2010

Infectious Bovine Rhinothracheitis (IBR) caused by bovine herpesvirus 1 (BoHV-1) infection is dis... more Infectious Bovine Rhinothracheitis (IBR) caused by bovine herpesvirus 1 (BoHV-1) infection is distributed worldwide. BoHV-1 either alone or in association with other respiratory cattle pathogens causes significant economic losses to the livestock industry. The aim of this work was to validate a guinea pig model as an alternative method to the current BoHV-1 vaccine potency testing in calves. Guinea pigs were immunized with two doses of vaccine, 21 days apart and sampled at 30 days post vaccination (dpv). BoHV-1 antibody (Ab) response to vaccination in guinea pigs, measured by ELISA and virus neutralization (VN), was statistically compared to the Ab response in cattle. The guinea pig model showed a dose-response relationship to the BoVH-1 antigen concentration in the vaccine and it was able to discriminate among vaccines containing 1 log 10 difference in its BoHV-1 concentration with very good repeatability and reproducibility (CV ≤ 20%). A regression analysis of the Ab titers obtained in guinea pigs and bovines at 30 and 60 dpv, respectively, allowed us to classify vaccines in three potency categories: "very satisfactory", "satisfactory" and "unsatisfactory". Bovines immunized with vaccines corresponding to each of these three categories were experimentally challenged with BoVH-1 virus, the level of protection, as measured by reduction of virus shedding and disease severity, correlated well with the vaccine category used. Data generated by 85 experiments, which included vaccination of calves and guinea pigs with 18 reference vaccines of known potency, 8 placebos and 18 commercial vaccines, was subjected to statistical analysis. Concordance analysis indicated almost perfect agreement between the model and the target species for Ab titers measured by ELISA and almost perfect to substantial agreement when Ab titers were measured by VN. Taken together these results indicate that the developed guinea pig model represents a novel and reliable tool to estimate batch-to-batch vaccine potency and to predict efficacy of killed BoHV-1 veterinary vaccines.

Journal of Virological Methods, 2009

Bovine Viral Diarrhea Virus (BVDV) is the causative agent of a worldwide disease. The virus infec... more Bovine Viral Diarrhea Virus (BVDV) is the causative agent of a worldwide disease. The virus infects bovines of all ages, causing reproductive problems and contaminating biological products of high commercial value. The large-scale production of BVDV vaccines presents the challenge of processing antigenic proteins that are highly susceptible to the processing environment. Potency testing requires the immunization of cattle in order to determine the neutralizing antibodies titers induced by the vaccine. An alternative to the in vivo test is an in vitro measurement of key viral antigens. This paper describes the development and validation of a sandwich-type indirect ELISA that is able to detect and quantify BVDV E2 glycoprotein in live and inactivated BVDV. Validation parameters such as repeatability, intermediate precision, and reproducibility indicated that the developed ELISA constitutes an advanced tool for evaluating the BVDV antigen throughout manufacturing and vaccine release testing.

Journal of Virological Methods, 2010

Two ELISAs to quantify antibodies to BoHV-1 in the sera of cattle and immunized guinea pigs were ... more Two ELISAs to quantify antibodies to BoHV-1 in the sera of cattle and immunized guinea pigs were developed and validated using ISO/IEC 17025 standards. The cut-off value of the assay was established at 20% positivity of a high positive control for screening of cattle. Using this threshold, the assay properly classified the OIE bovine reference sera EU1, EU2 and EU3. For vaccine potency testing, a cut-off of 40% was selected for both species. The reliability of the assays, given by their diagnostic sensitivity and specificity, using the threshold of 40% was 89.7% and 100%, respectively, for bovines and 94.9% and 100% for guinea pigs, respectively. There was almost perfect agreement between the ELISA and virus neutralization results. In addition, after vaccination, there was a good correlation between the neutralizing and ELISA antibody titers of the serum from the same bovine or guinea pig, sampled at 60 and 30 days post-vaccination, respectively (R(bovine)=0.88, R(guinea pig)=0.92; p<0.0001). A similar correlation was observed when analyzing the mean antibody titers of groups of vaccinated animals (R(bovine)=0.95 and R(guinea pig)=0.97; p<0.0001), indicating the relevance of the ELISAs for batch to batch vaccine potency testing in the target species and in the laboratory animal model. The intermediate precision of the assays expressed as the relative coefficient of variation (CV) of the positive control assayed over a 3-year period in the same laboratory was 22.2% for bovines and 23.1% for guinea pigs. The reproducibility of both techniques obtained in inter-laboratory assays was CV=12.4% for bovines and CV approximately 0 for guinea pigs, which met the requirements of the OIE…

Veterinary microbiology, Jan 17, 2011

Bovine Group A Rotavirus (RVA) is one of the main causes of neonatal calf diarrhea worldwide. The... more Bovine Group A Rotavirus (RVA) is one of the main causes of neonatal calf diarrhea worldwide. The present study reports the genotyping of bovine RVA strains circulating in Argentinean cattle from 2004 to 2010. Additionally, a new set of typing primers was designed and tested to differentiate between G8 and G6 (lineage III and IV) RVA strains. Bovine RVA was detected in 30% (435/1462) of the tested samples, corresponding to 49% (207/423) of the studied outbreaks with a similar detection rates in beef (53%; 67/127) and dairy herds (52%; 65/126). The RVA strains circulating in Argentinean cattle belonged to the common bovine genotypes G6 (lineages III and IV), G8, G10, P[5] and P[11]. A different RVA G/P-genotype distribution was found between the exploitation types, with the combination G6(IV)P[5] being by fare the most prevalent RVA strain in beef herds (58%), whereas a more even distribution of G6(III)P[11] (15%), G10P[11] (17%), G6(IV)P[5] (14%), and G6(IV)P[11] (6%) RVA strains wa...

Albéitar: publicación …, 2011

Información del artículo Diarrea neonatal del ternero.

Veterinary Immunology and Immunopathology, 2009

Our results demonstrate that immunization with LAM is able to induce a specific humoral immune re... more Our results demonstrate that immunization with LAM is able to induce a specific humoral immune response without interfering with IDR test usually used for bovine Tuberculosis diagnosis. It has been described that IgG1 is the predominant isotype in the immune response to LAM of infected animals Koets et al. (2001). Our results indicate that the same isotype profile is obtained when LAM is inoculated as a purified antigen. These results could support further investigations evaluating LAM as a candidate for a Paratuberculosis subunit vaccine.

Revista Argentina de Microbiología, 2014

Vaccine, Jan 16, 2010

Infectious Bovine Rhinothracheitis (IBR) caused by bovine herpesvirus 1 (BoHV-1) infection is dis... more Infectious Bovine Rhinothracheitis (IBR) caused by bovine herpesvirus 1 (BoHV-1) infection is distributed worldwide. BoHV-1 either alone or in association with other respiratory cattle pathogens causes significant economic losses to the livestock industry. The aim of this work was to validate a guinea pig model as an alternative method to the current BoHV-1 vaccine potency testing in calves. Guinea pigs were immunized with two doses of vaccine, 21 days apart and sampled at 30 days post vaccination (dpv). BoHV-1 antibody (Ab) response to vaccination in guinea pigs, measured by ELISA and virus neutralization (VN), was statistically compared to the Ab response in cattle. The guinea pig model showed a dose–response relationship to the BoVH-1 antigen concentration in the vaccine and it was able to discriminate among vaccines containing 1 log10 difference in its BoHV-1 concentration with very good repeatability and reproducibility (CV ≤ 20%). A regression analysis of the Ab titers obtaine...