Vaccination of Elk (Cervus canadensis) with Brucella abortus Strain RB51 Overexpressing Superoxide Dismutase and Glycosyltransferase Genes Does Not Induce Adequate Protection against Experimental Brucella abortus Challenge.

Pauline Nol,Steven G Hennager,Phillip J Sprino,Mo D Salman,Alana A Pavuk,Matthew P Mccollum,Jack C Rhyan,Stephen M Boyle,Randall J Berrier,Steven C Olsen,Nammalwar Sriranganathan

doi:10.3389/fcimb.2016.00010

Abstract

In recent years, elk (Cervus canadensis) have been implicated as the source of Brucella abortus infection for numerous cattle herds in the Greater Yellowstone Area. In the face of environmental and ecological changes on the landscape, the range of infected elk is expanding. Consequently, the development of effective disease management strategies for wild elk herds is of utmost importance, not only for the prevention of reintroduction of brucellosis to cattle, but also for the overall health of the Greater Yellowstone Area elk populations. In two studies, we evaluated the efficacy of B. abortus strain RB51 over-expressing superoxide dismutase and glycosyltransferase for protecting elk from infection and disease caused by B. abortus after experimental infection with a virulent B. abortus strain. Our data indicate that the recombinant vaccine does not protect elk against brucellosis. Further, work is needed for development of an effective brucellosis vaccine for use in elk.

Highlights

The persistence of brucellosis in wild elk (Cervus canadensis) remains a serious concern in the Greater Yellowstone Area (GYA)
Our results indicated that sRB51+SODc, WboA would not be effective in protecting elk from Brucella abortus infection
Based on encouraging data observed in mice (Vemulapalli et al, 2000a,b, 2002), we anticipated that mucosal vaccination with an RB51 strain that overexpresses both superoxide dismutase and glycosyltransferase, antigens that are immunogenic and associated with virulence, would elicit a protective response in elk

Summary

Introduction

The persistence of brucellosis in wild elk (Cervus canadensis) remains a serious concern in the Greater Yellowstone Area (GYA). Elk have been implicated as the source of infection for numerous cattle herds in Wyoming, Idaho, and Montana, USA (Hillman, 2002; Olsen et al, 2006; Rhyan et al, 2013). The development of effective disease management strategies for wild elk herds is of utmost importance, for the prevention of reintroduction of brucellosis to cattle, and for the overall health of the GYA elk populations. Available commercial vaccines for use in cattle (B. abortus strains 19 [s19] and RB51 [sRB51]) have offered little to no protection in elk against Brucella-induced abortion and infection (Cook et al, 2002; Kreeger et al, 2002; Olsen et al, 2002). Available commercial vaccines for use in cattle (B. abortus strains 19 [s19] and RB51 [sRB51]) have offered little to no protection in elk against Brucella-induced abortion and infection (Cook et al, 2002; Kreeger et al, 2002; Olsen et al, 2002). Vemulapalli et al (2000a,b, 2002) have shown that recombinant B. abortus sRB51 over-expressing antigenic factors in the form of either homologous Cu/Zn superoxide dismutase (SODc) or glycosyltransferase (encoded by wboA; McQuiston et al, 1999) intra-cytoplasmically (sRB51+SODc, WboA), induces an enhanced immune response and greater protection against B. abortus challenge in mice as compared to vaccination with sRB51 alone

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