RESUMO
UNLABELLED: Foot-and-mouth disease (FMD) is a highly contagious viral disease affecting biungulate species. Commercial vaccines, formulated with inactivated FMD virus (FMDV), are regularly used worldwide to control the disease. Here, we studied the generation of antibody responses in local lymphoid tissues along the respiratory system in vaccinated and further aerosol-infected cattle. Animals immunized with a high-payload monovalent FMD vaccine developed high titers of neutralizing antibodies at 7 days postvaccination (dpv), reaching a plateau at 29 dpv. FMDV-specific antibody-secreting cells (ASC), predominantly IgM, were evident at 7 dpv in the prescapular lymph node (LN) draining the vaccination site and in distal LN draining the respiratory mucosa, although in lower numbers. At 29 dpv, a significant switch to IgG1 was clear in prescapular LN, while FMDV-specific ASC were detected in all lymphoid tissues draining the respiratory tract, mostly as IgM-secreting cells. None of the animals (n = 10) exhibited FMD symptoms after oronasal challenge at 30 dpv. Three days postinfection, a large increase in ASC numbers and rapid isotype switches to IgG1 were observed, particularly in LN-draining virus replication sites already described. These results indicate for the first time that systemic FMD vaccination in cattle effectively promotes the presence of anti-FMDV ASC in lymphoid tissues associated with the respiratory system. Oronasal infection triggered an immune reaction compatible with a local anamnestic response upon contact with the replicating FMDV, suggesting that FMD vaccination induces the circulation of virus-specific B lymphocytes, including memory B cells that differentiate into ASC soon after contact with the infective virus. IMPORTANCE: Over recent decades, world animal health organizations as well as national sanitary authorities have supported the use of vaccination as an essential component of the official FMD control programs in both endemic and disease-free settings. Very few works studied the local immunity induced by FMD vaccines at the respiratory mucosa, and local responses induced in vaccinated animals after aerosol infection have not been described yet. In this work, we demonstrate for the first time that systemic FMD vaccination (i) induced the early presence of active antigen-specific ASC along the respiratory tract and (ii) prompted a rapid local antibody response in the respiratory mucosa, triggered upon oronasal challenge and congruent with a memory B-cell response. This information may help to understand novel aspects of protective responses induced by current FMD vaccines as well as to provide alternative parameters to establish protection efficiency for new vaccine developments.
Assuntos
Anticorpos Antivirais/imunologia , Vírus da Febre Aftosa/fisiologia , Febre Aftosa/prevenção & controle , Vacinação , Vacinas Virais/farmacologia , Replicação Viral/efeitos dos fármacos , Administração por Inalação , Animais , Células Produtoras de Anticorpos/imunologia , Bovinos , Febre Aftosa/imunologia , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Vacinas Virais/imunologia , Replicação Viral/imunologiaRESUMO
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.
Assuntos
Variação Antigênica/imunologia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/imunologia , Vírus da Diarreia Viral Bovina/imunologia , Filogenia , Regiões 5' não Traduzidas/genética , Sequência de Aminoácidos , Animais , Variação Antigênica/genética , Argentina , Sequência de Bases , Doença das Mucosas por Vírus da Diarreia Viral Bovina/genética , Bovinos , Vírus da Diarreia Viral Bovina/genética , Cobaias , Dados de Sequência Molecular , Testes de Neutralização/veterinária , RNA Viral/química , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Alinhamento de Sequência , Análise de Sequência de DNA , Proteínas do Envelope Viral/química , Proteínas do Envelope Viral/genéticaRESUMO
Mice immunized with a soluble extract of Neospora caninum tachyzoites (sNcAg) formulated with Providean-AVEC, an aqueous soy-based adjuvant, are fully protected from N. caninum multiplication. Here we evaluated the dose-dependent immunogenicity of this vaccine formulation in cattle. Cattle (N=3 per group) were immunized with two applications (30 days apart) of formulations containing Providean-AVEC and different payloads of sNcAg (100, 50 and 10 µg), that were five to fifty times lower than the only reported study using this same antigen in cattle. Kinetics and magnitude of the vaccine-induced immune responses were dose-dependent. Cattle immunized with 100 µg-sNcAg elicited high-avidity specific antibodies 3 weeks after the primary vaccination while those that received 50 µg of antigen had maximum levels of specific high-avidity antibodies 5 days after the day 30 boost. Vaccination with 10 µg of sNcAg induced comparable antibody responses after 2 weeks post re-vaccination. IgG1 was the predominant isotype in all vaccinated animals. Maximum systemic IFN-γ levels were measured in cattle immunized with 50 and 100 µg-sNcAg (14 ± 2.8 ng/ml). CD4(+)-T cells from vaccinated animals proliferated after sNcAg stimulation in vitro, producing IFN-γ. Recall IFN-γ responses mediated by CD4(+)-T cells were detected up to 140 days post vaccination. Formulations containing Providean-AVEC and 50 µg of sNcAg stimulated broad cellular and humoral immune responses against N. caninum in cattle. The profile and magnitude of the immune response elicited by this vaccine can be modified by the antigen-dose and vaccination schedule. This is the first dose-response study performed in cattle using sNcAg as antigen.
Assuntos
Doenças dos Bovinos/prevenção & controle , Coccidiose/veterinária , Lecitinas/química , Neospora/imunologia , Vacinas Protozoárias/imunologia , beta-Glucanas/química , Animais , Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/imunologia , Bovinos , Coccidiose/prevenção & controle , Relação Dose-Resposta a Droga , Ensaio de Imunoadsorção Enzimática/veterinária , Técnica Indireta de Fluorescência para Anticorpo/veterinária , Testes SorológicosRESUMO
Foot-and-mouth disease (FMD) is a highly contagious viral disease which affects both domestic and wild biungulate species. This acute disease, caused by the FMD virus (FMDV), usually includes an active replication phase in the respiratory tract for up to 72 h postinfection, followed by hematogenous dissemination and vesicular lesions at oral and foot epithelia. The role of the early local adaptive immunity of the host in the outcome of the infection is not well understood. Here we report the kinetics of appearance of FMDV-specific antibody-secreting cells (ASC) in lymphoid organs along the respiratory tract and the spleen in cattle infected by aerosol exposure. While no responses were observed for up to 3 days postinfection (dpi), all animals developed FMDV-ASC in all the lymphoid organs studied at 4 dpi. Tracheobronchial lymph nodes were the most reactive organs at this time, and IgM was the predominant isotype, followed by IgG1. Numbers of FMDV-ASC were further augmented at 5 and 6 dpi, with an increasing prevalence in upper respiratory organs. Systemic antibody responses were slightly delayed compared with the local reaction. Also, IgM was the dominant isotype in serum at 5 dpi, coinciding with a sharp decrease of viral RNA detection in peripheral blood. These results indicate that following aerogenous administration, cattle develop a rapid and vigorous genuine local antibody response throughout the respiratory tract. Time course and isotype profiles indicate the presence of an efficient T cell-independent antibody response which drives the IgM-mediated virus clearance in cattle infected by FMDV aerosol exposure.
Assuntos
Imunidade Adaptativa , Anticorpos Antivirais/sangue , Doenças dos Bovinos/imunologia , Vírus da Febre Aftosa/imunologia , Febre Aftosa/imunologia , Sistema Respiratório/imunologia , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Células Produtoras de Anticorpos/imunologia , Bovinos , Doenças dos Bovinos/virologia , Febre Aftosa/virologia , Imunoglobulina G/biossíntese , Imunoglobulina G/sangue , Isotipos de Imunoglobulinas/biossíntese , Isotipos de Imunoglobulinas/sangue , Isotipos de Imunoglobulinas/imunologia , Imunoglobulina M/biossíntese , Imunoglobulina M/sangue , Linfonodos/imunologia , Sistema Respiratório/virologia , Baço/imunologia , Carga Viral/imunologiaRESUMO
The current report was prompted by an atypical outbreak of mucosal disease that occurred in a beef herd in the southwestern part of Buenos Aires Province, Argentina, where a total of 9/41 (21.9%) yearling bulls died. Blood samples from 73 bulls and 189 heifers were tested for evidence of persistent BVDV infection with Bovine Viral Diarrhea Virus (BVDV). Non-cytopathic BVDV was isolated from 7 (9.6%) 24- to 36-month-old bulls, and 3 (1.6%) 36-month-old heifers. Non-cytopathic BVDV was also detected in the seminal plasma of three of six persistently infected (PI) bulls. Furthermore, a 171 bp genomic fragment of BVDV was consistently detected by nested RT-PCR in one of the two samples of the commercial semen used for artificial insemination, indicating that this semen could be a possible source of infection for the whole herd. To evaluate the possible reproductive consequences of PI heifers and bulls, ovaries and semen were obtained from PI cattle for in vitro assays. The in vitro fertilization of oocytes with semen from PI bulls was associated with decreased cleavage and embryo development rates. Additionally, non-cytopathic BVDV was isolated from the follicular fluid of PI heifers. Genetic typing revealed that all isolates BVDV from the present study had a high percentage of homology and that all of the fragments from the RT-PCR clearly fit with the BVDV 1b cluster. These findings confirm the negative impact that BVDV can have on the reproductive performance of cattle and the importance of applying the proper sanitary controls to minimize the risk of BVDV infection.