Nanoparticle-Based Delivery of Anaplasma marginale Membrane Proteins; VirB9-1 and VirB10 Produced in the Pichia pastoris Expression System

Abstract

Bovine anaplasmosis or cattle-tick fever is a tick-borne haemolytic disease caused by the rickettsial haemoparasite Anaplasma marginale in tropical and subtropical areas of the world. While difficult to express, the proteins VirB9-1 and VirB10 are immunogenic components of the outer membrane type IV secretion system that have been identified as candidate antigens for vaccines targeting of A. marginale. Soluble VirB9-1 and VirB10 were successfully expressed using Pichia pastoris. When formulated with the self-adjuvanting silica vesicles, SV-100 (diameter: 50 nm, and pore entrance size: 6 nm), 200 µg of VirB9-1 and VirB10 were adsorbed per milligram of nanoparticle. The VirB9-1 and VirB10, SV-100 formulations were shown to induce higher antibody responses in mice compared to the QuilA formulations. Moreover, intracellular staining of selected cytokines demonstrated that both VirB9-1 and VirB10 formulations induced cell-mediated immune responses in mice. Importantly, the SV-100 VirB9-1 and VirB10 complexes were shown to specifically stimulate bovine T-cell linages derived from calves immunised with A. marginale outer membrane fractions, suggesting formulations will be useful for bovine immunisation and protection studies. Overall this study demonstrates the potential of self-adjuvanting silica vesicle formulations to address current deficiencies in vaccine delivery applications.

Characterization of the Biodistribution of a Silica Vesicle Nanovaccine Carrying a Rhipicephalus (Boophilus) microplus Protective Antigen With in vivo Live Animal Imaging

“…The Rhodamine-labeled SV-140 (diameter 50 nm, wall thickness 6 nm, perforated by pores with an entrance size 16 nm and total pore volume of 0.934 cm 3 g −1 ) were prepared and labeled as described in Mody et al ( 2014a ), Zhang et al ( 2014 ), and Zhang et al ( 2016 ). Cy5-labeled Bm86 (Cy5-Bm86) was prepared using the Abcam's manufacturer protocol (ab188288–Cy5 Fast Conjugation Kit).…”

“…Our research over the last decade has focused on developing a platform technology using MSNs as antigen carriers and adjuvants for developing a nanovaccine with reduced number of injections, induction of long-term immune responses, and improved dose storage capacity. We have thoroughly investigated the potential of one class of MSNs, silica vesicles (SVs), as self-adjuvanting antigen carriers to develop successful vaccine delivery systems targeting bovine viral diarrhea virus-1 (mucosal disease) (Mahony et al, 2013 , 2014 ; Mody et al, 2014a , b ): Anaplasma marginale (anaplasmosis) (Zhang et al, 2016 ) and Theileria parva (East Coast Fever). In all of our studies, SVs successfully delivered the antigen of interest and initiated both humoral and cell-mediated immune responses.…”

Topical review on nano-vaccinology: Biochemical promises and key challenges

“…Heterosubtypic immune protection in influenza strains (H1N1, H5N1) is a much-needed approach for rapidly mutating viruses [ 31 , 32 ]. A highly significant pathogen of humans, including HBV, HPV, HIV, DENV-E have been prevented using precisely engineered nano vaccines, that have shown to offer up to 95-100% effective immune protection [ 33 ]. Anti-AIDS nano-vaccines may be utlilized at clilnical settings to prevent the disease and associated complications at endemic regions of the world.…”

“…Drug resistance and slower development of modern anti-parasitic drugs are the major concern to widespread neglected tropical diseases. Parasitic diseases of prime concern like-wise: leishmaniasis, malaria, toxoplasmosis, anaplasmosis, schistosomiasis, and coccidiosis have been treated and prevented using several forms of nanoparticles [ 33 , 37 ]. To date, there is no commercially available nano-vaccine against any parasite.…”

Applications of Nanovaccines for Disease Prevention in Cattle

“…However, purification of OM proteins is cost prohibiting, therefore, the use of subunit vaccines in combination with novel delivery platforms is particularly promising. Nano platforms have been explored in A. marginale vaccines including silica vesicles (SV100) carrying type IV secretion system proteins (T4SS) VirB9-1 and VirB9-2 (Zhao et al, 2016;Zhao L. et al, 2017), and VirB9-1 and VirB10 proteins (Zhang et al, 2016), as well as carbon nanotubes carrying the major surface protein (MSP)1a (Pimentel et al, 2020), in the mouse model. These formulations induce both cell-mediated and humoral responses that are protective against challenge; however, they have not been tried in cattle.…”