Immunocompetent truncated E2 glycoprotein of bovine viral diarrhea virus (BVDV) expressed in Nicotiana tabacum plants: a candidate antigen for new generation of veterinary vaccines.

The bovine viral diarrhea virus (BVDV) is the etiological agent responsible for a wide spectrum of clinical diseases in cattle. The glycoprotein E2 is the major envelope protein of this virus and the strongest inductor of the immune response. There are several available commercial vaccines against bovine viral diarrhea (BVD), which show irregular performances.

Rapid methodology for antigenic profiling of FMDV field strains and for the control of identity, purity and viral integrity in commercial virus vaccines using monoclonal antibodies.

Monoclonal antibodies (MAbs) developed against different foot-and-mouth disease virus (FMDV) vaccine strains were extensively used to study any possible antigenic variations during vaccine production in Argentine facilities. Additionally, a typing ELISA using strain specific MAbs was developed to detect potential cross contaminations among FMDV strains in master and working seeds with high specificity and sensitivity and to confirm strains identity in formulated vaccines. This assay was carried out for the South American strains currently in use in production facilities in Argentina (A24/Cruzeiro, A/Argentina/01, O1/Campos and C3/Indaial) and for the strain O/Taiwan, produced only for export to Asia.

Detection by RT-PCR and genetic characterization of canine distemper virus from vaccinated and non-vaccinated dogs in Argentina.

RT-PCR was used to detect canine distemper virus (CDV) RNA in clotted blood from Argentine domestic dogs. The NP gene was detected in 73 out of 99 blood samples analyzed. The deduced amino acid sequence of these gene fragments showed 100% identity with the sequence of other wild-type and vaccine strains.

Characterization of infectious bursal disease viruses from Argentina.

Infectious bursal disease (IBD) viruses detected in commercial flocks of different regions of Argentina were analyzed by reverse transcription-polymerase chain reaction-restriction fragment length polymorphism (RFLP) of a VP2 gene fragment, followed by sequence analysis. Two out of eight IBD viruses presented an SspI restriction site, typical of the very virulent phenotype. Three IBD viruses presented a SacI restriction site, typical of classic virulent strains, and one isolate presented restriction sites for both enzymes.

Analysis of the immune response to FMDV structural and non-structural proteins in cattle in Argentina by the combined use of liquid phase and 3ABC-ELISA tests.

The successful sanitary campaign implemented to control the 2000-2002 outbreaks of foot-and-mouth disease virus (FMDV) in Argentina was greatly assisted by the combination of an ELISA test (3ABC-ELISA) that detects antibodies directed against FMDV viral non-structural proteins (NSPs) and a liquid phase blocking competitive ELISA (lpELISA) for the detection of antibodies against the viral structural proteins (SPs). The combined use of these two assays in large-scale analysis of field samples allowed for a clear differentiation between infected and uninfected animals, with high specificity and sensitivity, regardless of the animal's vaccination status. In order to validate the application in indirect vaccine potency assays and assessment of vaccination efficiency, a preliminary correlation between serological response and protection from challenge with O1/Campos and A/Arg/01 FMD virus strains was established with data derived from commercial vaccine series challenge trials.

Reintroduction of foot-and-mouth disease in Argentina: characterisation of the isolates and development of tools for the control and eradication of the disease.

This paper describes the antigenic and molecular characterisation of foot-and-mouth disease virus (FMDV) strains isolated during the 2000-2002 epidemic in Argentina, and the strategy implemented for disease control. Two different FMDV serotypes, O and A, were involved. Of the various field isolates studied, two distinct O1 lineages (strains Corrientes/00 and Misiones/00) and two serotype A lineages (A/Argentina/00 and A/Argentina/01 prototypes) were identified.