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.
Highlights
Anaplasma marginale, an intra-erythrocytic gram negative bacterium, is a rickettsial haemoparasite of cattle, causing anaplasmosis or cattle-tick fever
In this study we investigated the use of P. pastoris as an expression system to produce soluble recombinant VirB9-1 and VirB10 proteins
NanomRateercioalms 2b01in6,a6n, 2t0V1 irB9-1 and VirB10 were successfully expressed using the P. pastoris system3 oafn1d6 purified from the culture media using metal affinity chromatography (Figure 1)
Summary
An intra-erythrocytic gram negative bacterium, is a rickettsial haemoparasite of cattle, causing anaplasmosis or cattle-tick fever. The acute phase of this tick-borne disease is characterised by severe anaemia, weight loss, fever, abortion, lower milk production and often death [1]. After recovery from acute infection, cattle remain persistently infected without clinical signs, acting as reservoirs for transmission by ticks to other cattle [2]. The major surface proteins (MSPs) play an important role in the interaction of A. marginale with host immune system, and the antibody responses are primarily directed towards MSP2 and MSP3. As the genes encoding these proteins can undergo continuous rearrangement the resulting antigenic variation means that immune responses to MSP2 and MSP3 do not confer life-long protection [3]. The high variability of these proteins makes them unsuitable for inclusion in vaccines targeting A. marginale
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
