318 Abstracts / Veterinary Immunology and Immunopathology 128 (2009) 211–347 milk samples will be tested by a more sensitive PCR tech- nique. doi:10.1016/j.vetimm.2008.10.229 Construction of immunodiagnostic and therapeutic bovine antibodies as single chain Fv (scFv) Madhuri Koti 1,* , Eva Nagy 2 , Azad K. Kaushik 1 1 Department of Molecular and Cellular Biology, University of Guelph, Canada 2 Department of Pathobiology, University of Guelph, Canada Keywords: scFv; Immunodiagnostic; Bovine antibody E-mail address: mkoti@uoguelph.ca (M. Koti). Species: Ruminants Our lab has been engaged in defining the structural and functional aspects of bovine antibodies that demon- strated limited germline antibody diversity both at the heavy (V H ,D H and J H gene elements) and light chain (V L and J L gene elements) locus in cattle. These studies also demon- strated that some of the cattle antibodies are amongst the largest known because of an exceptionally long variable region influenced by an atypical CDR3H. Since antibod- ies are important in immunodiagnostics, clinical diagnosis and immunotherapy, engineering of antibodies as minimal antigen binding fragments, e.g. scFv provides an important strategic approach. For these reasons we have expressed bovine IgG antibody as scFv with different linker sizes. The expressed bovine IgG, as scFvs with different linker sizes, are indeed functional as revealed by various immunological assays. These experiments have led to conclude that bovine antibodies can be expressed as scFvs that are functional and can be produced in large amounts in an appropriate system, which are of definitive immunodiagnostic and therapeutic potential. Supported by NSERC research grant, Canada. doi:10.1016/j.vetimm.2008.10.230 Characterization of specific immune responses in cattle immunized with plasmid DNA construct and recom- binant Semliki Forest virus particles encoding Cu,Zn superoxide dismutase (SOD) of Brucella abortus Angel A. O˜ nate * , Darwin R. Sáez, Ingrid I. Guzmán, Edilia M. Andrews, Alex C. Cabrera Molecular Immunology Laboratory, Department of Microbiol- ogy, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile Keywords: Genetic vaccine; Brucella abortus; DNA vaccine; RNA vaccine E-mail address: aonate@udec.cl (A.A. O ˜ nate). Species: Ruminants The immune responses of cattle immunized with a plasmid DNA construct and a recombinant Semliki For- est virus (SFV) particles expressing the Cu,Zn superoxide dismutase (SOD) of Brucella abortus was studied in cattle. We have previously demonstrated in mice that plasmid DNA carrying the SOD gene (pcDNA-SOD) and the SFV particles carrying recombinant RNA encoding SOD (SFV- SOD) were able to induce a protective immune response that correlated with induction of antigen-specific lym- phoproliferation, INF- production and cytotoxic activity. Two independent trials were conducted in cattle to deter- mine the ability of these two genetic vaccines to elicit antigen-specific immune responses. Cattle injected intra- muscularly with pcDNA-SOD, but not the control plasmid pc DNA3, developed a significant, but weak, SOD-specific IgG antibodies of predominantly IgG1 isotype. In addition, the DNA vaccine elicited a SOD-specific T-cell prolifera- tive response. Animals vaccinated with SFV-SOD did not develop SOD-specific antibodies, at least until week 10 after immunization (the end of the experiment), and in vitro stimulation of their peripheral blood mononuclear cells (PBMC) exhibited a significant T cell immune response. In both experiments secretion of gamma interferon, IL- 4 or TNF- by the lymphocytes was not detected upon in vitro stimulation with SOD. These results suggest the potential of using pcDNA-SOD or SFV-SOD to induce cellu- lar immune response in cattle against a protective antigen of Brucella. This is the first reported vaccination study in a target host Species with DNA or RNA vaccines against Brucella. Supported by grant 1010851 and 1050054 from the Fondo Nacional de Investigación Científica y Tecnologíca (FONDECYT), Santiago, Chile. doi:10.1016/j.vetimm.2008.10.231 Semliki Forest virus that encodes a Brucella abortus IF3 protein protects BALB/c mice against infection Alex C. Cabrera * , Darwin R. Sáez, Edilia M. Andrews, Angel A. O ˜ nate Molecular Immunology Laboratory, Department of Microbiol- ogy, Faculty of Biological Sciences, Universidad de Concepcion, Chile Keywords: Vaccine; Brucella abortus; Intracellular pathogens E-mail address: acabrera@udec.cl (A.C. Cabrera). Species: OtherBrucella abortus, is a causal agent of the bovine brucellosis. In Chile, the disease is controlled by the vaccination with B. abortus strain RB51 however some dis- advantages have been described, as the capacity to revert to the virulent form. Within the new technologies of vaccina- tion appear vectors based on the Semliki Forest virus (VSF). These consist of suicidal viral particles, whit an autoreplica- ble genome that only codifies for an interest protein. In this study we evaluated the immune response induced by viral particles of VSF able to express the protein IF3 of B. abor- tus (VSF-IF3). For it, 4 groups of 10 females BALB/c mice was immunized with PBS, VSF-lac-Z, VSF-IF3 or B. abor- tus strain RB51 evaluating the cellular immune response