Recipient Organization
VST LLC
101 N MAIN AVE
SIOUX FALLS,SD 57104
Performing Department
(N/A)
Non Technical Summary
Tick-borne pathogens cause major economic losses to the livestock industry, leading to an estimated $19.7 billion in losses for the U.S., including approximately $3 billion in losses for cattle producers. Among the 900 species of ticks, the Asian longhorned tick (ALT), an invasive, non-native tick species, poses a major threat to animal health and productivity in cattle and other livestock. Currently, tick management includes inspection and chemical control and can be a tedious and expensive process for livestock producers. Unfortunately, there are no vaccines in the U.S. that target ALT. Medgene Labs will develop the first U.S.-based ALT anti-tick vaccine, which will be baculovirus derived and administered as a 1- or 2-dose regimen. This vaccine will significantly reduce the cost, time, and effort associated with herd management. This Phase I project will 1) develop a vaccine that targets ALT infestations and 2) assess the immunogenicity of the vaccine in cattle through serological assays. Successful completion of our Phase I project will generate critical proof-of-concept data to support larger vaccine study trials in Phase II to establish the utility of our vaccine against tick-borne disease in cattle and will provide a model for the development of effective vaccines against other tick species native to the U.S. Anticipated Phase II work will lead to submission of an Investigational New Animal Drug Application to the FDA's Center for Veterinary Medicine and enable the rapid deployment of an ALT vaccine to prevent tick-borne illness.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Goals / Objectives
This first goal of the project is todevelop a baculovirus vaccine that targets the Asian longhorned tick. To achieve this objective, Medgene Labs will develop a vaccine construct encoding a U.S.-specific Hl86 protein to ensure target specificity of the resulting vaccine. The Hl86 protein produced by our scalable baculovirus system will be combined with our proprietary W:O:W adjuvant, ARMOR, for use in animal studies.The second goal is to assess the immunogenicity of the Asian longhorned tick vaccine in cattle. To provide initial in vivo validation of the proposed Asian longhorned tick vaccine, Medgene Labs will evaluate the immunogenic response to the vaccine in cattle. One-dose and 2-dose regimens will be tested, and antibody titers will be quantified by ELISA assays
Project Methods
Medgene Labs' established baculovirus system for prescription platform vaccine production will be used to produce a novel vaccine construct designed to drive the expression of Hl86, the 68-kDa H. longicornis ortholog of the Bm86 glycoprotein, which was the target antigen for previous anti-tick vaccines. The U.S.-specific Hl86 sequence will be obtained from Asian longhorned tick samples collected from U.S. sites and sequenced. A modified Hl86 cDNA sequence will be sent to IDT for synthesis. The modifications introduced for vaccine production include EcoRI and NotI restriction sites for cloning purposes and sequences encoding a C-terminal TEV protease site followed by a His tag and stop codon. The sequence also contains sites that correspond to PCR and sequencing primers that will be used to perform quality control analysis during vaccine production. Medgene vaccine serials will be produced at Medgene Labs utilizing Outline of Production 9PP0.R0. The vaccine construct will be produced by subcloning the Hl86 coding sequence into the pBacPAK8 vector, which will then be inserted into the BestBac 2.0 baculovirus genome via co-transfection into Sf9 cells. The resulting Master Seeds will be validated and used to infect cells for antigen production. All Medgene serials will be adjuvanted with Medgene Labs' proprietary ARMOR W:O:W adjuvant. Actual serial formulation records, including lot numbers, will be available upon request, and included in the final project report. Vaccines will be stored at 2-8°C until use.To assess the immune response of the vaccinated animals, whole blood will be collected in 10-ml serum separator tubes (SST) on Days 0, 28, 40, and 60 per the schedule of events (Table 1). The tubes will be labeled with the animal's ID tag number. After collection, the samples will be placed on ice packs in a cooler until delivery to Medgene Labs. The sample collection will be documented on the sample collection record. Serum samples will be prepared by allowing the whole blood samples to clot for 1 hour at room temperature and centrifuging the samples for 15 minutes at 1,300×g. For each sample, two ≥0.5-ml serum aliquots will be stored at or below -20°C. Titers of specific antibodies to Hl86 will be determined by ELISA. Briefly, 96- well plates will be coated with Hl86 antigen, and blocked serum samples will then be added and diluted 2-fold across the plate. Following incubation, a species-specific detection antibody will be added to detect bound antibody. The plates will include positive and negative controls to monitor assay performance. The results will be reported as the dilution at which Hl86-specific antibodies are no longer detected.