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Spontaneous murine thymocyte comitogenic activity consistent with interleukin-1 in cattle naturally infected with
J M Kreeger1, T G Snider, B M Olcott
1Veterinary Medical Diagnostic Laboratory, University of Missouri, Columbia 65211.
Insights
Cattle with paratuberculosis show increased interleukin-1 (IL-1) production by monocytes, suggesting non-specific activation or a regulatory defect. This finding is crucial for understanding immune responses in bovine paratuberculosis.
Area of Science:
- Immunology
- Veterinary Medicine
- Microbiology
Background:
- Paratuberculosis is a chronic infectious disease in cattle caused by Mycobacterium avium subspecies paratuberculosis.
- Interleukin-1 (IL-1) is a key cytokine involved in immune regulation and inflammation.
- Monocytes play a critical role in the innate immune response to pathogens.
Purpose of the Study:
- To investigate the production of IL-1-like activity by blood monocytes from cattle naturally infected with paratuberculosis.
- To determine IL-1-like activity in response to homologous and heterologous antigens in infected and non-infected cattle.
Main Methods:
- Murine thymocyte proliferation assay was used to measure comitogenic activity.
- Blood monocytes from nine infected and six non-infected cattle were isolated.
- Cells were stimulated with Mycobacterium paratuberculosis antigen (johnin), lipopolysaccharide (LPS), M. bovis PPD, and KLH.
Main Results:
- Monocytes from paratuberculosis-infected cattle spontaneously released high levels of IL-1-like activity.
- Infected cattle monocytes showed increased IL-1 activity in response to LPS.
- Non-infected cattle showed significantly increased IL-1 activity upon stimulation with various antigens, with johnin eliciting the strongest response.
Conclusions:
- Blood monocytes in cattle with paratuberculosis appear to be non-specifically activated concerning IL-1 production.
- A defective regulatory mechanism for IL-1 may be present in infected cattle.
- Mycobacterial antigens were confirmed as potent inducers of IL-1.
Abstract:
The production of comitogenic activity consistent with interleukin-1 (IL-1) activity by blood monocytes from cattle with naturally acquired paratuberculosis was examined by murine thymocyte proliferation. In addition, IL-1-like activity in response to homologous and heterologous antigens was determined. Activity was determined in nine cattle naturally infected with Mycobacterium paratuberculosis and six non-infected cattle. Comitogenic properties were measured in response to M. paratuberculosis antigen (johnin), bacterial lipopolysaccharide (LPS) as a positive control, and culture media as a negative control. Monocytes from infected cattle spontaneously released high levels of IL-1-like activity in the absence of stimuli and significantly (P less than 0.05) increased activity in response to LPS. With johnin, M. bovis PPD and KLH stimulation, comitogenic activity was similar to spontaneous levels. Non-infected cattle had significantly (P less than 0.05) increased comitogenic activity when blood monocytes were stimulated with KLH, M. bovis PPD, johnin, and lipopolysaccharide when compared with non-stimulated cells in that group. Johnin produced the greatest response in non-infected animals. The data suggest that blood monocytes in infected cattle are non-specifically activated with respect to IL-1 production. Alternatively, a defective regulatory mechanism for IL-1 may be operative in infected cattle. In addition, the previous observation that mycobacterial antigens are potent inducers of IL-1 was also verified.