FMD vaccine matching: Inter laboratory study for improved understanding of r values.

Foot-and-mouth disease virus (FMDV) is a highly variable RNA virus existing as seven different serotypes. The antigenic variability between and within serotypes can limit the cross-reactivity and therefore the in vivo cross-protection of vaccines. Selection of appropriate vaccine strains is crucial in the control of FMD.

RT-PCR and sequence analysis of the full-length fusion protein of Canine Distemper Virus from domestic dogs.

During 2007-2014, 84 out of 236 (35.6%) samples from domestic dogs submitted to our laboratory for diagnostic purposes were positive for Canine Distemper Virus (CDV), as analyzed by RT-PCR amplification of a fragment of the nucleoprotein gene. Fifty-nine of them (70.

Development of a nanoparticle-based oral vaccine for Atlantic salmon against ISAV using an alphavirus replicon as adjuvant.

Adjuvants used in vaccine aquaculture are frequently harmful for the fish, causing melanosis, granulomas and kidney damage. Along with that, vaccines are mostly administered by injection, causing pain and stress to the fish. We used the DNA coding for the replicase of alphavirus as adjuvant (Ad) of a vaccine against ISAV.

Evaluation of the immune response elicited by vaccination with viral vectors encoding FMDV capsid proteins and boosted with inactivated virus.

The aim of the present study was to assess the effect of introducing a priming step with replication-defective viral vectors encoding the capsid proteins of FMDV, followed by a boost with killed virus vaccines, using a suitable BALB/c mice model. Additionally, the immune response to other combined vector immunization regimens was studied. For this purpose, we analyzed different prime-boost immunizations with recombinant adenovirus (Ad), herpesvirus amplicons (Hs) and/or killed virus (KV) vaccines.

The fusion protein signal-peptide-coding region of canine distemper virus: a useful tool for phylogenetic reconstruction and lineage identification.

Canine distemper virus (CDV; Paramyxoviridae, Morbillivirus) is the etiologic agent of a multisystemic infectious disease affecting all terrestrial carnivore families with high incidence and mortality in domestic dogs. Sequence analysis of the hemagglutinin (H) gene has been widely employed to characterize field strains, permitting the identification of nine CDV lineages worldwide. Recently, it has been established that the sequences of the fusion protein signal-peptide (Fsp) coding region are extremely variable, suggesting that analysis of its sequence might be useful for strain characterization studies.

Characterization of a type O foot-and-mouth disease virus re-emerging in the year 2011 in free areas of the Southern Cone of South America and cross-protection studies with the vaccine strain in use in the region.

Molecular, antigenic and vaccine matching studies, including protective response in vivo, were conducted with a foot-and-mouth disease type O virus isolated during the outbreak in September 2011 in San Pedro, Paraguay, country internationally recognized as free with vaccination in 1997. The phylogenetic tree derived from complete VP(1) sequences as well as monoclonal antibody profiling indicated that this isolate was related to viruses responsible for previous emergencies in free areas of the Southern Cone of South America occurring sporadically between the years 2000 and 2006. Marked differences with the vaccine strain O(1)/Campos, including the loss of reactivity with neutralizing MAbs, were recognized.

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.

Evidence of two co-circulating genetic lineages of canine distemper virus in South America.

Canine distemper virus (CDV) is the etiological agent of a multisystemic infection that affects different species of carnivores and is responsible for one of the main diseases suffered by dogs. Recent data have shown a worldwide increase in the incidence of the disease, including in vaccinated dog populations, which necessitates the analysis of circulating strains. The hemagglutinin (H) gene, which encodes the major antigenic viral protein, has been widely used to determine the degree of genetic variability and to associate CDVs in different worldwide circulating lineages.

Characterization of foot-and-mouth disease virus from outbreaks in Ecuador during 2009-2010 and cross-protection studies with the vaccine strain in use in the region.

During the years 2009 and 2010 relevant epidemic waves of foot-and-mouth disease (FMD) serotype O occurred in Ecuador, representing a great drawback for the last stages of the ongoing eradication program in South America. This study describes the molecular and antigenic characterizations of 29 isolates collected from various regions in the country and their relationship to the vaccine strain. The phylogenetic tree derived from sequences spanning the complete VP(1) protein showed that, despite the widespread origin of the viruses, they were all related among themselves and to previous isolates occurring in 2008, with around 10% difference with the vaccine strain O1/Campos.

Study of canine parvovirus evolution: comparative analysis of full-length VP2 gene sequences from Argentina and international field strains.

The continuous emergence of new strains of canine parvovirus (CPV), poorly protected by current vaccination, is a concern among breeders, veterinarians, and dog owners around the world. Therefore, the understanding of the genetic variation in emerging CPV strains is crucial for the design of disease control strategies, including vaccines. In this paper, we obtained the sequences of the full-length gene encoding for the main capsid protein (VP2) of 11 canine parvovirus type 2 (CPV-2) Argentine representative field strains, selected from a total of 75 positive samples studied in our laboratory in the last 9 years.

Evolution of canine parvovirus in Argentina between years 2003 and 2010: CPV2c has become the predominant variant affecting the domestic dog population.

The current frequency of Canine Parvovirus variants (CPV2a, CPV2b and CPV2c) in the Argentine dog population was investigated by PCR amplification of a 583 bp fragment in the VP2 gene. From a total of 79 rectal swab samples that have been submitted to our laboratory since 2008, 55 (69.6%) resulted positive and were further analyzed by direct DNA sequencing.

HSV-1 amplicon vectors that direct the in situ production of foot-and-mouth disease virus antigens in mammalian cells can be used for genetic immunization.

HSV-1 amplicon vectors encoding heterologous antigens were capable to mediate in situ generation of protein synthesis and to generate a specific immune response to the corresponding antigens. In this study, foot-and-mouth disease (FMD) virus antigens were used to generate a genetic vaccine prototype. The amplicons were designed to provide a high safety profile as they do not express any HSV-1 genes when packaged using a helper virus-free system, and they are able to encapsidate several copies of the transgene or allow the simultaneous expression of different genes.

Confidence in indirect assessment of foot-and-mouth disease vaccine potency and vaccine matching carried out by liquid phase ELISA and virus neutralization tests.

The necessity of avoiding the use of animals in vaccine potency testing has been widely recognized. The repeatability and reproducibility of the Expected Percentage of Protection (EPP) as a serological potency surrogate for A24 Cruzeiro foot-and-mouth disease virus (FMDV) strain was assessed, and compared with the results obtained with challenge in the Protection against Podal Generalization (PPG) test. To determine the EPPs, the serum titers obtained by liquid phase blocking competitive ELISA (lpELISA) and virus neutralization (VNT) in 10 potency trials using the same A24 Cruzeiro vaccine, were interpolated into previously validated logit transformation curves that correlate PPG with serology.

Quantitative single serum-dilution liquid phase competitive blocking ELISA for the assessment of herd immunity and expected protection against foot-and-mouth disease virus in vaccinated cattle.

A single serum-dilution liquid phase ELISA (slpELISA) was standardized to be used for serological evaluation of herd immunity against foot-and-mouth disease. The absorbance value at a dilution 1:64 of each serum sample was interpolated in a standard curve by plotting the antibody titers of six control sera determined by end point dilution liquid phase ELISA (lpELISA), against the absorbance values for the same control sera at 1:64 dilutions. A straight line was obtained by linear regression analysis (r>0.

Molecular characterization of canine parvovirus strains in Argentina: Detection of the pathogenic variant CPV2c in vaccinated dogs.

PCR amplification with sequence-specific primers was used to detect canine parvovirus (CPV) DNA in 38 rectal swabs from Argentine domestic dogs with symptoms compatible with parvovirus disease. Twenty-seven out of 38 samples analyzed were CPV positive. The classical CPV2 strain was not detected in any of the samples, but nine samples were identified as CPV2a variant and 18 samples as CPV2b variant.

Some guidelines for determining foot-and-mouth disease vaccine strain matching by serology.

The selection of matching strains for use in outbreaks of foot-and-mouth disease (FMD) virus can be assessed in vivo or by serological r-value determination. Sera from animals involved in vaccine potency and cross-protection trials performed using the "Protection against Podal Generalization" (PPG) test for two serotype A strains were collected and analyzed by the virus neutralization test (VNT) and liquid-phase ELISA (lpELISA) in three laboratories. The average VNT r-values for medium and high serum titer classes from the A(24) Cruzeiro vaccinated animals were in line with the A/Arg/01 heterologous PPG outcome for all testing laboratories, suggesting that the vaccine strain A(24) Cruzeiro is unlikely to protect against the field isolate A/Arg/01.

Updating of the correlation between lpELISA titers and protection from virus challenge for the assessment of the potency of polyvalent aphtovirus vaccines in Argentina.

Routine vaccination campaigns are carried out in Argentina twice a year, involving more than 100 million doses of foot-and-mouth disease (FMD) vaccine. Although the challenge test in cattle has not been totally replaced for the assessment of FMD vaccine potency, Argentine Animal Health authorities have used an indirect alternative method based on specific correlation studies of protection against podal generalization (PPG) tests performed in cattle with a validated liquid phase blocking ELISA (lpELISA). The change of vaccine formulations that took place after the 2000-2001 outbreaks, generated a gap in the correlation between lpELISA titers and PPG for the new FMD virus strains.

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.

Intranasal immunization with a recombinant truncated FimH adhesin adjuvanted with CpG oligodeoxynucleotides protects mice against uropathogenic Escherichia coli challenge.

In this work, we assessed the efficacy of an experimental intranasal vaccine against urinary-tract infections. The vaccine contained a recombinant truncated FimH (rFimHt) adhesin plus CpG oligodeoxynucleotides. The efficacy of the vaccine was compared with that of an intramuscular vaccine that was formulated with the same immunogen plus Freund's adjuvant.

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.