RESUMEN
Infection with Bovine Viral Diarrhea Viruses (BVDV) in cattle results in a wide range of clinical manifestations, ranging from mild respiratory disease to fetal death and mucosal disease, depending on the virulence of the virus and the immune and reproductive status of the host. In this study 30 Argentinean BVDV isolates were characterized by phylogenetic analysis. The isolates were genotyped based on comparison of the 5' untranslated region (5' UTR) and the E2 gene. In both phylogenetic trees, 76% of the viruses were assigned to BVDV 1b, whereas BVDV 1a, 2a and 2b were also found. Eight of the BVDV 1b isolates were further characterized by cross-neutralization tests using guinea pig antisera and sera from bovines vaccinated with two different commercial vaccines. The results demonstrated the presence of a marked antigenic diversity among Argentinean BVDV isolates and suggest the need to incorporate BVDV 1b isolates in diagnostic strategies.
Asunto(s)
Variación Antigénica/inmunología , Diarrea Mucosa Bovina Viral/inmunología , Virus de la Diarrea Viral Bovina/inmunología , Filogenia , Regiones no Traducidas 5'/genética , Secuencia de Aminoácidos , Animales , Variación Antigénica/genética , Argentina , Secuencia de Bases , Diarrea Mucosa Bovina Viral/genética , Bovinos , Virus de la Diarrea Viral Bovina/genética , Cobayas , Datos de Secuencia Molecular , Pruebas de Neutralización/veterinaria , ARN Viral/química , ARN Viral/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/veterinaria , Alineación de Secuencia , Análisis de Secuencia de ADN , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/genéticaRESUMEN
The aim of this work was to determine the effects of cGnRH I pulse frequencies on FSH and LH release and the changes in features and number of cultured laying hen FSH-cells and LH-cells in vitro. Primary adenohypophyseal cell cultures taken from laying hens were stimulated by four 5 min pulses using 1 or 10 nM cGnRH, administered with interpulses between pulses at 15, 30 or 60 min. Pulse frequencies and dose dependent effects were examined in six separate experiments including two controls. After the last interpulse time, the supernatants were collected and stored at -70° C until the performance of an indirect enzyme-linked immunosorbent assay (ELISA) using chicken LH and chicken FSH antisera at 1:1000 and 1:2000 dilutions, respectively. Supernatants were coated in duplicate on the inner surface of Immulon 2 plates and later blocked with the optimal solutions. They were incubated with each antiserum and subsequently with isotype-specific peroxidase-labeled anti-rabbit antibodies. Hydrogen peroxide/o-phenylenediamine was added as substrate/chromogen and the optical density (OD) was determined at 492 nm. The ABC immunocytochemical method was performed to characterize and re-count the gonadotropes employing anti-chicken FSH and anti-chicken LH as primary antibodies. The number of FSH-LH cells was obtained using stereological analysis and the data were statistically processed. The ODs obtained for each anti-hormone were compared with the control groups and with each other. Significant differences were found in number of aggregated-positive LH cells, which decreased with 1 nM cGnRH-I, 15 vs. 30 min pulses, increased with 30 vs. 60 min pulses, and also with 10 nM cGnRH-I, 30 vs. 60 min pulses. Aggregated positive FSH cells, however, did not show significant differences in percentage at any GnRH dose or pulse frequencies, but did show activity at low pulse frequencies of 15 and 30 min. The results suggest that LH cells varied in percentage in a dose dependent manner at higher pulse frequency (15 min) and were dose independent at low pulse frequency (60 min) and showed inactive features; while FSH cell numbers were unaffected showing features of activity at low pulse frequencies. High and moderate pulse frequencies of cGnRH-I (15-30 min) increased the FSH release in dose independent manner without changes in features or percentage of FSH cells. Low pulse frequency (60 min) of cGnRH-I increased LH release dose independently disminished LH cell percentage and showed changes in cells' features. These results in avian cells showed differences in responses to GnRH pulse frequencies from those reported earlier in mammals.
Asunto(s)
Gonadotrofos/efectos de los fármacos , Hormona Liberadora de Gonadotropina/farmacología , Animales , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Pollos , Relación Dosis-Respuesta a Droga , Hormona Folículo Estimulante/análisis , Hormona Folículo Estimulante/metabolismo , Gonadotrofos/citología , Gonadotrofos/metabolismo , Hormona Luteinizante/análisis , Hormona Luteinizante/metabolismo , Adenohipófisis/efectos de los fármacos , Factores de TiempoRESUMEN
Protection against BHV-5 disease induced by inactivated BHV-1 or BHV-5 based vaccines was analysed. Two groups of calves were subcutaneously immunized with an inactivated BHV-1 or BHV-5 based vaccine. A third group was not vaccinated and used as control. In the post-vaccination period, we studied the humoral and cellular immune response resulting similar to both groups. The efficacy of the vaccines was tested after intranasal challenge of the calves with a virulent Argentinean BHV-5 isolate (A-663). All control animals developed neurological signs associated with BHV-5 infection and high levels of virus shedding. Calves immunized with the BHV-1 and BHV-5 inactivated vaccines were protected against BHV-5 disease. Our study provides evidence that strongly support the existence of cross-protection between BHV-1 and BHV-5 in calves. Even though this has already been suggested by previous works, this is the first time an exhaustive study of the immune response is performed and typical clinical BHV-5 meningoencephalitis signs are reproduced in an experimental BHV-5 challenge trial.
Asunto(s)
Infecciones por Herpesviridae/veterinaria , Herpesvirus Bovino 1/inmunología , Herpesvirus Bovino 5/inmunología , Vacunas Virales/inmunología , Animales , Anticuerpos Antivirales/sangre , Bovinos , Línea Celular , Encefalitis Viral/prevención & control , Encefalitis Viral/veterinaria , Encefalitis Viral/virología , Infecciones por Herpesviridae/prevención & control , Infecciones por Herpesviridae/virología , Meningoencefalitis/prevención & control , Meningoencefalitis/veterinaria , Meningoencefalitis/virología , Pruebas de Neutralización/veterinaria , Esparcimiento de VirusRESUMEN
The objective of this study was to compare the immune response to Neospora caninum in naturally infected heifers and heifers inoculated with a killed whole N. caninum tachyzoite preparation during the second trimester of gestation. Nine Holstein heifers were used in this study; three naturally infected heifers were born from seropositive dams, and six seronegative heifers were born from seronegative dams. Four seronegative heifers were subcutaneously vaccinated with a killed whole N. caninum tachyzoite preparation at weeks 13, 15 and 17 of gestation. A killed whole N. caninum tachyzoite preparation containing 45 mg of protein/5 ml dose was formulated with 70% of mineral oil adjuvant (13% consisting of Arlacel C, 85% Marcol 52 and 2% Tween-80). Similarly, two seronegative heifers (negative controls) were inoculated with mock-infected bovine monocytes in oil adjuvant. Humoral immune responses were tested by using an indirect fluorescent antibody test (IFAT) and an indirect enzyme-linked immunosorbent assay (ELISA) for detecting isotype specific antibodies. Cellular immune responses were assessed by lymphocyte proliferation test (LPT) and IFN-gamma production. N. caninum-specific antibody responses increased in immunized cattle by week 15 of gestation (mean reciprocal antibody titers 450+/-252), peaked at week 23 (mean 16,000+/-6400). Maximum antibody response in naturally infected heifers was observed at week 19 of gestation (mean: 3467+/-2810). Mean serum IFAT titers were significantly higher in immunized heifers compared with those in naturally infected heifers from weeks 17 to 25 (P < 0.05). Analysis of isotype specific antibodies in naturally infected heifers revealed a predominant IgG1 response in one heifer and a predominant IgG2 response in the other two. Similar titers of IgG1 and IgG2 occurred in immunized heifers. Control heifers remained seronegative throughout the study by IFAT and ELISA. Significant antigen-specific proliferation responses were only detected in naturally infected heifers in week 19 of gestation. Peripheral mononuclear blood cells (PMBC) from immunized animals produced IFN-gamma in similar concentrations to those of infected animals (P > 0.05). No abortion was seen in any experimental group; however, one calf from a vaccinated heifer died due to dystocia. All calves from vaccinated and control heifers were seronegative by IFAT at 6 months of age; in contrast, calves born from naturally infected heifers remained seropositive with titers > or = 200. Killed vaccine induced similar immune responses to those found in chronically, naturally infected cattle which did not abort; however, different immune pathways may be followed in vaccinated and natural infected heifers with differences in degree of protective immunity.
Asunto(s)
Enfermedades de los Bovinos/inmunología , Enfermedades de los Bovinos/parasitología , Coccidiosis/veterinaria , Transmisión Vertical de Enfermedad Infecciosa/veterinaria , Neospora/inmunología , Vacunas Antiprotozoos/inmunología , Vacunación/veterinaria , Animales , Animales Recién Nacidos , Anticuerpos Antiprotozoarios/sangre , Bovinos , Enfermedades de los Bovinos/prevención & control , Enfermedades de los Bovinos/transmisión , Proliferación Celular , Coccidiosis/inmunología , Coccidiosis/parasitología , Coccidiosis/prevención & control , Ensayo de Inmunoadsorción Enzimática/veterinaria , Femenino , Técnica del Anticuerpo Fluorescente Indirecta/veterinaria , Isotipos de Inmunoglobulinas/inmunología , Transmisión Vertical de Enfermedad Infecciosa/prevención & control , Interferón gamma/inmunología , Masculino , Vacunas Antiprotozoos/uso terapéutico , Distribución Aleatoria , Linfocitos T/citología , Linfocitos T/inmunologíaRESUMEN
The antibody and cell mediated immune responses induced by BHV-1 were analysed in cattle after vaccination and challenge exposure to the virulent strain LA of BHV-1. Animals were vaccinated intramuscularly (IM) with inactivated virus vaccines against BHV-1 containing either a water in mineral oil adjuvant (W/O), a water in mineral oil adjuvant plus Avridine (W/O+Avridine) or sulfolipo-cyclodextrin in squalane in-water emulsion (SL-CD/S/W). No significant differences were registered in the antibody response induced by the three evaluated vaccines. However, the BHV-1 specific cell-mediated immunite response was stronger and appeared earlier when SL-CD/S/W was included in the formulation. The efficacy of the vaccines was also evaluated after intranasal challenge of the calves with a virulent BHV-1 LA strain. Animals vaccinated with SL-CD/S/W had reduced virus excretion and clinical symptoms compared with the mock-vaccinated animals. Comparison of levels of BHV-1 specific IgG2 and IgG1 with virus shedding revealed that, regardless of the adjuvant administered, animals showing BHV-1 specific IgG2/IgG1 ratios higher than 1 were those with a significant lower number of individuals shedding virus. Additionally, animals vaccinated with SL-CD/S/W presented no post-vaccinal reactions. These factors, combined with the higher efficacy and the ease of manipulation of the biodegradable oil, makes the vaccine formulated with this new adjuvant an important contribution for the veterinary vaccines industry.
Asunto(s)
Adyuvantes Inmunológicos/administración & dosificación , Ciclodextrinas/administración & dosificación , Herpesvirus Bovino 1/inmunología , Rinotraqueítis Infecciosa Bovina/prevención & control , Escualeno/análogos & derivados , Vacunas de Productos Inactivados/administración & dosificación , Vacunas Virales/administración & dosificación , Animales , Anticuerpos Antivirales/análisis , Formación de Anticuerpos/efectos de los fármacos , Bovinos , Ciclodextrinas/inmunología , Emulsiones/administración & dosificación , Inmunidad Celular/efectos de los fármacos , Inmunoglobulina G/análisis , Activación de Linfocitos/inmunología , Aceite Mineral/administración & dosificación , Pruebas de Neutralización , Escualeno/administración & dosificación , Escualeno/inmunología , Vacunas de Productos Inactivados/inmunología , Vacunas Virales/inmunología , Esparcimiento de Virus/inmunología , Agua/administración & dosificaciónRESUMEN
Examination of the stomach and spiral valve contents of 41 Sympterygia bonapartei Müller and Henle, 1841 (Rajiformes: Rajidae) from the Bahía Blanca estuary (38 degrees 42'S, 62 degrees 28'W), revealed the presence of the nematode Proleptus acutus Dujardin, 1845. The prevalence was 34.1% and the mean intensity was 5.75. Sympterygia bonapartei is a new host and is endemic to southern Brazil, Uruguay, and Argentina. The occurrence of P. acutus constitutes the first finding in Argentinian waters.