Lawsonia intracellularis is an obligate intracellular bacteria causing proliferative enteropathy (PE) in pigs. The infection causes diarrhoea, retarded growth and sudden death, and is one of the major causes of antibiotics usage in modern pig production. In experimental L. intracellularis infection studies an IFN-γ assay was developed based on overnight incubation of heparin-stabilised whole blood with L. intracellularis (SDS-antigen) in the presence of IL-18. The produced IFN-γ was quantified by ELISA. High levels of IFN-γ was measured from 2 weeks p.i. in pigs infected at 12 weeks of age, however pigs infected at 5 weeks of age exhibited a much lower level of IFN-γ response. After clearing the infection in the young pigs (from 3 weeks p.i.), these pigs mounted a high antigen-specific IFN-γ response 7 weeks p.i., even when no signs of L. intracellularis infection was detected. Pigs receiving a primary L. intracellularis infection at 5 weeks of age followed by a challenge infection at 12 weeks of age showed increased or constant high levels of IFN-γ after challenge. These pigs were protected against L. intracellularis re-infection in contrast to age matched challenge control pigs, which developed L. intracellularis infection. Four-color flow cytometry was used to identify cells producing IFN-γ after co-incubation of PBMCs with SDS-antigen and IL-18. IFN-γ producing cells were mostly identified as CD4+, and especially CD4+CD8+ double positive T-cells also expressing CD25.
|Published - 2009
|3rd European Veterinary Immunology Workshop - Berlin, Germany
Duration: 1 Sept 2009 → 13 Sept 2009
Conference number: 3rd
|3rd European Veterinary Immunology Workshop
|01/09/2009 → 13/09/2009
- Lawsonia intracellularis