Abstract
Development of veterinary subunit vaccines comes with a spectrum of challenges, such as the choice of adjuvant, antigen delivery vehicle, and optimization of dosing strategy. Over the years, our laboratory has largely focused on investigating silica vesicles (SVs) for developing effective veterinary vaccines for multiple targets. Rhipicephalus microplus (cattle tick) are known to have a high impact on cattle health and the livestock industry in the tropical and subtropical regions. Development of vaccine using Bm86 antigen against R. microplus has emerged as an attractive alternative to control ticks. In this study, we have investigated the biodistribution of SV in a live animal model, as well as further explored the SV ability for vaccine development. Rhodamine-labeled SV-140-C18 (Rho-SV-140-C18) vesicles were used to adsorb the Cy5-labeled R. microplus Bm86 antigen (Cy5-Bm86) to enable detection and characterization of the biodistribution of SV as well as antigen in vivo in a small animal model for up to 28 days using optical fluorescence imaging. We tracked the in vivo biodistribution of SVs and Bm86 antigen at different timepoints (days 3, 8, 13, and 28) in BALB/c mice. The biodistribution analysis by live imaging as well as by measuring the fluorescent intensity of harvested organs over the duration of the experiment (28 days) showed greater accumulation of SVs at the site of injection. The Bm86 antigen biodistribution was traced in lymph nodes, kidney, and liver, contributing to our understanding how this delivery platform successfully elicits antibody responses in the groups administered antigen in combination with SV. Selected tissues (skin, lymph nodes, spleen, kidney, liver, and lungs) were examined for any cellular abnormalities by histological analysis. No adverse effect or any other abnormalities were observed in the tissues.
Highlights
The beef cattle industry makes an important contribution to the global economy
We have thoroughly investigated the potential of one class of mesoporous silica nanoparticles (MSNs), silica vesicles (SVs), as self-adjuvanting antigen carriers to develop successful vaccine delivery systems targeting bovine viral diarrhea virus-1 (Mahony et al, 2013, 2014; Mody et al, 2014a,b): Anaplasma marginale (Zhang et al, 2016) and Theileria parva (East Coast Fever)
Western blot analysis of the fluorescently labeled nanovaccine formulation demonstrated the Cy5-labeled Bm86 retained its native antigenicity as it was recognized by the antibodies in serum from a sheep immunized with the unlabeled antigen from a previous study (Figure 1)
Summary
The beef cattle industry makes an important contribution to the global economy. In the recent years (2017–2018), it accounted for around 20% ($12.3 billion) of the total gross value of farm production. Ticks and tick-borne diseases have a serious impact on the global stock farming industry by negatively affecting the cattle health and production. Different approaches such as chemical acaricides and vaccines have been investigated to control cattle ticks. Because of environmental and chemical-resistance issues associated with the use of acaricides, alternative solutions are required. One of the potential solutions is vaccination, which is increasingly preferred and is sought after to provide a long-term solution for more effective management of this pest
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
