Duration of protection and humoral immunity induced by an adenovirus-vectored subunit vaccine for foot-and-mouth disease (FMD) in Holstein steers.

Foot-and-mouth disease (FMD) is a highly contagious viral infection of cloven hooved animals that continues to cause economic disruption in both endemic countries or when introduced into a formally FMD free country. Vaccines that protect against clinical disease and virus shedding are critical to control FMD. The replication deficient human adenovirus serotype 5 (Ad5) vaccine vector expressing empty FMD virus (FMDV) capsid, AdtFMD, is a promising new vaccine platform. With no shedding or spreading of viral vector detected in field trials, this vaccine is very safe to manufacture, as there is no requirement for high containment faciitites. Here, we describe three studies assessing the proportion of animals protected from clinical vesicular disease (foot lesions) following live-FMDV challenge by intradermolingual inoculation at 6 or 9 months following a single vaccination with the commercial AdtFMD vaccine, provisionally licensed for cattle in the United States. Further, we tested the effect of vaccination route (transdermal, intramuscular, subcutaneous) on clinical outcome and humoral immunity. Results demonstrate that a single dose vaccination in cattle with the commercial vaccine vector expressing capsid proteins of the FMDV strain A24 Cruzeiro (Adt.A24), induced protection against clinical FMD at 6 months (100% transdermal, 80% intramuscular, and 60% subcutaneous) that waned by 9 months post-vaccination (33% transdermal and 20% intramuscular). Post-vaccination serum from immunized cattle (all studies) generally contained FMDV specific neutralizing antibodies by day 14. Anti-FMDV antibody secreting cells are detected in peripheral blood early following vaccination, but are absent after 28 days post-vaccination. Thus, the decay in antibody mediated immunity over time is likely a function of FMDV-specific antibody half-life. These data reveal the short time span of anti-FMDV antibody secreting cells (ASCs) and important performance characteristics of needle-free vaccination with a recombinant vectored subunit vaccine for FMDV.

A modern approach for epitope prediction: identification of foot-and-mouth disease virus peptides binding bovine leukocyte antigen (BoLA) class I molecules.

Major histocompatibility complex (MHC) class Imolecules regulate adaptive immune responses through the presentation of antigenic peptides to CD8+ T cells. Polymorphisms in the peptide binding region of class I molecules determine peptide binding affinity and stability during antigen presentation, and different antigen peptide motifs are associated with specific genetic sequences of class I molecules. Understanding bovine leukocyte antigen (BoLA), peptide-MHC class I binding specificities may facilitate development of vaccines or reagents for quantifying the adaptive immune response to intracellular pathogens, such as foot-and-mouth disease virus (FMDV). Six synthetic BoLA class I (BoLA-I) molecules were produced, and the peptide binding motif was generated for five of the six molecules using a combined approach of positional scanning combinatorial peptide libraries (PSCPLs) and neural network-based predictions (NetMHCpan). The updated NetMHCpan server was used to predict BoLA-I binding peptides within the P1 structural polyprotein sequence of FMDV (strain A24 Cruzeiro) for Bo-LA-1*01901, BoLA-2*00801, BoLA-2*01201, and BoLA-4*02401. Peptide binding affinity and stability were determined for these BoLA-I molecules using the luminescent oxygen channeling immunoassay (LOCI) and scintillation proximity assay (SPA). The functional diversity of known BoLA alleles was predicted using theMHCcluster tool, and functional predictions for peptide motifs were compared to observed data from this and prior studies. The results of these analyses showed that BoLA alleles cluster into three distinct groups with the potential to define BBoLA supertypes.^ This streamlined approach identifies potential T cell epitopes from pathogens, such as FMDV, and provides insight into T cell immunity following infection or vaccination.

An alternate delivery system improves vaccine performance against foot-and-mouth disease virus (FMDV).

Foot-and-mouth disease virus (FMDV) causes vesicular disease of cloven-hoofed animals with severe agricultural and economic implications. One of the most highly infectious and contagious livestock pathogens known, the disease spreads rapidly in naïve populations making it critical to have rapidly acting vaccines. Needle inoculation of killed virus vaccine is an efficient method of swiftly vaccinating large numbers of animals, either in eradication efforts or in outbreak situations in disease free countries, although, to be efficient, this requires utilizing the same needle with multiple animals. Here we present studies using a needle free system for vaccination with killed virus vaccine, FMDV strain O1 Manisa, as a rapid and consistent delivery platform. Cattle were vaccinated using a commercially available vaccine formulation at the manufacturer's recommended dose as well as four and sixteen fold less antigen load per dose. Animals were challenged intradermalingually (IDL) with live, virulent virus, homologous strain O1 Manisa, at various times following vaccination. All non-vaccinated control cattle exhibited clinical disease, including fever, viremia and lesions, specifically vesicle formation. Cattle vaccinated with the 1/16× and 1/4× doses using the needle free device were protected when challenged at both 7 and 28 days after vaccination. These data suggest that effective protection against disease can be achieved with 1/16 of the recommended vaccine dose when delivered using the needle free, intradermal delivery system, indicating the current vaccine stockpile that can be extended by many fold using this system.

Environmental Salmonella surveillance in the Ohio State University Veterinary Teaching Hospital.

Sampling was conducted at The Ohio State University's Veterinary Teaching Hospital (OSU-VTH) to evaluate the extent of environmental contamination with Salmonella enterica, at 1-week intervals beginning March 19, 2007, through May 21, 2007. Environmental samples were collected from various surface and floor locations in the equine and food animal areas using sterile moistened gauze sponges. All samples were processed using standard bacteriologic culture to identify the presence of Salmonella spp. Genetic relatedness of isolates was assessed using amplified fragment length polymorphism (AFLP) procedures, and minimum inhibitory concentrations to a panel of antimicrobial drugs were determined using microbroth dilution. A total of 16 Salmonella isolates were recovered from 270 (5.9%) cultured environmental and animal samples, with prevalence ranging from 0% to 32% on individual sampling dates. A total of 9% of the samples from the food animal section and 2.5% of the samples from the equine section tested positive for Salmonella (p = 0.03). The 16 isolates represented seven different clonal strains and four different serotypes (Paratyphi B var. L-tartate n = 3, Kentucky n = 5, Cerro n = 7, Montevideo n = 1), most of which were pansusceptible to a panel of antimicrobial drugs. Our results indicate that animal treatment areas with a high population of animals or cases within the veterinary teaching hospital can become contaminated with Salmonella, especially in high traffic areas that may facilitate horizontal dissemination. The most common occurrence appears to be infected agricultural animals that contaminate the hospital environment, but normal cleaning and disinfection appears to effectively prevent long-term contamination.