Groups of 15 laboratory-bred beagles were vaccinated and boosted with either a placebo or adjuvanted bivalent bacterin comprised of a traditional Borrelia burgdorferi strain and a unique ospA- and ospB-negative B. burgdorferi strain that expressed high levels of OspC and then challenged with B. burgdorferi-infected Ixodes scapularis ticks. The vaccinated dogs produced high titers of anti-OspA and anti-OspC borreliacidal antibodies, including borreliacidal antibodies specific for an epitope within the last seven amino acids at the OspC carboxy terminus (termed OspC7) that was conserved among pathogenic Borrelia genospecies. In addition, spirochetes were eliminated from the infected ticks that fed on the bacterin recipients, B. burgdorferi was not isolated from the skin or joints, and antibody responses associated specifically with canine infection with B. burgdorferi were not produced. In contrast, B. burgdorferi was recovered from engorged ticks that fed on 13 (87%) placebo-vaccinated dogs (P<0.0001), skin biopsy specimens from 14 (93%) dogs (P<0.0001), and joint tissue specimens from 8 (53%) dogs (P=0.0022). In addition, 14 (93%) dogs developed specific antibody responses against B. burgdorferi proteins, including 11 (73%) with C6 peptide antibodies (P<0.0001). Moreover, 10 (67%) dogs developed Lyme disease-associated joint abnormalities (P<0.0001), including 4 (27%) dogs that developed joint stiffness or lameness and 6 (40%) that developed chronic joint inflammation (synovitis). The results therefore confirmed that the bacterin provided a high level of protection against Lyme disease shortly after immunization.
Overlapping fragments of the bovine herpesvirus-1 (BHV-1) glycoprotein (gD) ORF were expressed as trpE-gD fusion proteins in Escherichia coli to map linear neutralizing epitopes defined by BHV-1-specific MAbs. The MAbs 3402 and R54 reacted with the expressed fragments on Western blots that located the epitopes between the amino acids 52-126 and 165-216, respectively, of gD. Bovine covalescent sera with high neutralizing antibody titers against BHV-1 reacted with these bacterially expressed proteins containing both of the epitopes. Alignment of these sequences from BHV-1 with the corresponding region of the BHV-5 gD ORF sequences (reported here) identified several amino acid mismatches. Since the MAbs 3402 and R54 neutralize the BHV-1 and not BHV-5, it was presumed that these were important amino acids in defining the epitope. To further localize the neutralizing epitopes, synthetic peptides corresponding to these regions in the BHV-1 gD ORF were tested for their capacity to block monoclonal antibody neutralization of BHV-1 infectivity. The peptides encompassing amino acids 92-106 (3402 epitope) and amino acids 202-213 (R54 epitope) of the BHV-1 gD competed with BHV-1 for the binding by MAbs 3402 and R54, respectively, in a dose-dependent manner. Antisera produced in rabbits to these peptides conjugated to a carrier reacted strongly with a 30-kDa protein by Western blotting and had neutralizing antibody titers against BHV-1.
The modified-live BVDV vaccine protected calves against systemic infection and disease after experimental challenge exposure with NY-1 BVDV. The vaccine protected calves against infection and viremia and prevented infection of target lymphoid cells.
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