Brucellosis and pseudorabies lead to abortion in pregnant sows and are perpetuated by feral swine reservoirs. A multivalent oral vaccine for these diseases would improve vaccination and eradication programs worldwide. Previous studies have shown that the rough attenuated Brucella strains RB51 and VTRS1, when administered subcutaneously to swine, stimulate host immune responses, transiently colonize tissues, and provide partial protection against virulent B. suis infection in pregnant sows. A plasmid encoding for the pseudorabies virus glycoprotein D (PRV gD) has also been added to these strains as part of this project. This study evaluates the use of these strains as oral vaccines for swine brucellosis and investigates the ability of these vaccines to colonize lymph nodes and stimulate the production of antibodies against rough Brucella antigens and PRV gD. Orally administered VTRS1 stimulated a higher immune response than RB51 in a shorter period of time, transiently colonized lymph nodes, and did not lead to the production of anti-O-polysaccharide (OPS) antibodies that interfere with brucellosis diagnostic tests. Both RB51 and VTRS1 provided substantial litter protection in orally vaccinated sows challenged with virulent B. suis; however, VTRS1, unlike RB51, also provided partial protection in the sow. These studies support the use of orally administered VTRS1 as an efficacious vaccine for swine brucellosis. The addition of a plasmid encoding for PRV gD to these strains created the multivalent vaccines RB51+gD and VTRS1+gD. Compared to the above strains, the addition of the plasmid did not alter immune response stimulation to rough Brucella antigens and these vaccines were safe when administered to pregnant sows. Swine vaccinated with RB51+gD or VTRS1+gD exhibited low immune responses to the gD antigen and delayed tissue colonization by the vaccine strains. It was found that plasmid addition slowed the growth of the vaccine strains in the laboratory, which may account for the suppressed tissue colonization and immune responses to the PRV gD antigen in swine. Further studies are necessary to evaluate the use of these strains as multivalent vaccines for brucellosis and pseudorabies in swine.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-10122004-191951 |
| Date | 13 October 2004 |
| Creators | Molin, Lorraine Harrow |
| Contributors | Dennis French, Frederick Enright, Philip Elzer |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-10122004-191951/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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