Enzyme-linked immunosorbent assay and immunoblot analysis of the immunoglobulin G response to whole-cell and lipooligosaccharide antigens of Pasteurella pneumotropica in laboratory mice with latent pasteurellosis.

The immunoglobulin G (IgG) response to whole-cell and lipooligosaccharide (LOS) antigens of Pasteurella pneumotropica was evaluated in mice with latent pasteurellosis by enzyme-linked immunosorbent assay (ELISA) and immunoblots. Antibodies to cell wall proteins of P. pneumotropica also reacted with several protein antigens from isolates of Actinobacillus spp. and other pasteurellae. Conversely, antibodies to LOS antigens of P. pneumotropica demonstrated no cross-reactivity with LOSs of other Pasteurella or Actinobacillus species. IgG to cell wall proteins was detected initially by ELISA 4 weeks after experimental oronasal inoculation of specific-pathogen-free mice; antibody to LOSs was first detected 7 weeks after infection and at that time exceeded titers to other cell wall antigens. Naturally infected conventional mice from a colony with endemic latent pasteurellosis had high IgG titers to P. pneumotropica antigens at 8 to 10 weeks of age, and, as in the experimentally infected mice, antibody to LOSs predominated. Thus, LOSs of P. pneumotropica can be used as an ELISA or immunoblot antigen to detect serospecific antibodies in laboratory mice with latent pasteurellosis.