No abstract

Hartman, E.G., van Houten, M., Frik, J.F. and van der Donk, J.A., 1984. Humoral immune response of dogs after vaccination against leptospirosis measured by an IgM-and IgG-specific ELISA. Vet. Immunol. Immunopathol., 7: 245-254.An IgM-and IgG-specific ELISA was used to measure the antibody response stimulated in dogs by vaccination with a leptospiral bacterin containing chemically inactivated Leptospira interrogans serotype icterohaemorrhagiae and serotype canicola leptospires. All dogs produced anti-leptospiral IgM and IgG. The IgM production was of the primary response type after each vaccination (primary vaccination, booster vaccination and annual revaccination). A substantial antileptospiral IgG response could be demonstrated only after the first booster vaccination and the annual revaccination. Annual revaccination resulted in a higher and much longer persisting IgG response than did the first booster vaccination. A revision of the vaccination scheme is suggested.

The role of Serpula hyodysenteriae hemolysin in the pathogenesis of swine dysentery was studied. The inactivation of a gene, tly, encoding a hemolysin, and the virulence of a tly− mutant in mice is reported. We obtained chromosomal integration of the distrupted tly gene via homologous recombination in a S. hyodysenteriae wild‐type strain following electroporation. A plasmid construct, in which the tly gene was disrupted by a kanamycin‐resistance gene, was used for the electroporation. The mutants obtained had reduced hemolysis indicating that the tly encoded hemolysin is not the only hemolysin produced by S. hyodysenteriae. Mice infected with the tly− mutant had fewer cecal lesions than mice infected with the wild‐type S. hyodysenteriae. From these results it was concluded that the tly encoded hemolysin may be an important virulence factor, but not the only one. It was demonstrated that gene transfer to spirochaetes can be achieved through electroporation.

Genomes of 55 Dutch porcine Serpulina (Treponema) hyodysenteriae ran& nsn-pathogenic Serpulina isolates were characterized by restriction endonuclease analysis (REA) and DNA hybridization. Tt me h t c h porcine isolates were compared with American Type Culture Collection (ATCC) strains of S. hyodysenferiae and S. innocens and isolates of S. hyodysenferiae with known serotypes (reference strains). REA of the Dutch S. hyodysenteriae isolates resulted in two main patterns, while the non-pathogenic isolates had many distinct REA patterns, all different from the S. hyodysenferiae strains. The S. hyodysenteriae reference strains all had distinct REA patterns, different from the Dutch strains. Upon Southern hybridization with a S. hyodysenferiae DNA fragment encoding a flagellar protein, all S. hyodysenteriae strains could be divided in two groups. The non-pathogenic Serpulina strains had many distinct hybridization patterns and hybridized less intensely. Upon hybridization with a S. hyodysenteriae DNA fragment encoding a haemolysin, DNA of all S. hyodysenteriae strains reacted in the same band. DNA of non-pathogenic Dutch Serpulina strains and S. innocens did not hybridize. It was concluded that there are two main genotypes of S. hyodjwenteriae in the Netherlands. This could be of importance for recombinant DNA vaccine development.

Hartman, E.G., van Houten, M., van der Donk, J.A. and Frik, J.F., 1984.Determination of specific anti-leptospiral immunoglobulins M and G in sera of experimentally infected dogs by solid-phase enzyme-linked immunosorbent assay. Vet. Immunol. Immunopathol., 7: 43-51.