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Cellular immune responses of the rat to experimental infection with Dermatophilus congolensis
J P Woodman1, A M Morrow, I Heron
1Centre for Tropical Veterinary Medicine, Roslin, Midlothian, Great Britain.
Abstract:
The host cell-mediated immune response was examined following experimentally-induced infection of rats with Dermatophilus congolensis, the causal agent of the skin disease dermatophilosis. Mononuclear cells (MC) isolated from Wistar rats 10 days following the induction of a third infection underwent a strong and specific proliferative response, as assessed by a [3H]thymidine incorporation assay, when cultured with various concentrations of inactivated D. congolensis cocci. Using specific monoclonal antibodies in an indirect fluorescent antibody test, this in vitro response was found to be characterised by a large expansion of the W3/25 (T-helper phenotype) population to form 56% of the total. Finally, the primed and stimulated MC were assessed for their ability to produce factors capable of inhibiting macrophage migration. The culture supernatants of D. congolensis-stimulated MC from infected rats caused significant migration inhibition of normal rat peritoneal exudate cells, whilst the supernatants of similarly-stimulated MC from naive rats failed to cause significant inhibition. The results show that a MC subpopulation becomes primed following experimentally-induced infection with D. congolensis and becomes activated after subsequent, in vitro, exposure.
Insights
Host cell-mediated immunity to Dermatophilus congolensis was studied in rats. Infected rats showed a specific immune cell proliferation and activation, indicating a primed response to the dermatophilosis pathogen.
Area of Science:
- Immunology
- Veterinary Dermatology
- Microbiology
Background:
- Dermatophilus congolensis causes dermatophilosis, a significant skin disease in animals.
- Understanding the host immune response is crucial for managing this infection.
Purpose of the Study:
- To investigate the host cell-mediated immune response in rats experimentally infected with D. congolensis.
- To characterize the immune cell populations involved and their functional capabilities.
Main Methods:
- Experimental infection of Wistar rats with D. congolensis.
- Isolation and in vitro stimulation of mononuclear cells (MC).
- [3H]thymidine incorporation assay for cell proliferation.
- Indirect fluorescent antibody test using monoclonal antibodies.
- Macrophage migration inhibition assay using culture supernatants.
Main Results:
- D. congolensis-specific MC proliferation was observed in infected rats.
- A significant expansion of the T-helper cell (W3/25) population was detected.
- Culture supernatants from stimulated MC of infected rats inhibited normal rat macrophage migration.
Conclusions:
- Experimentally induced D. congolensis infection primes a specific host cell-mediated immune response in rats.
- Activated mononuclear cells produce factors that inhibit macrophage migration, suggesting a role in dermatophilosis pathogenesis.