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Updated: Aug 14, 2026
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Published on: September 28, 2016
Cytokine expression in porcine lungs experimentally infected with Mycoplasma hyopneumoniae
Héctor Lorenzo1, Oscar Quesada, Patricia Assunçao
1Department of Comparative Pathology, Veterinary Faculty, University of Las Palmas de Gran Canaria, Trasmontaña s/n, 35416 Arucas, Gran Canaria, Spain.
Abstract:
To gain further insight into the pathogenesis of porcine enzootic pneumonia (PEP), cytokine expression in different pulmonary compartments was examined. Mycoplasma hyopneumoniae (Mh) and proinflammatory and immunoregulatory cytokines (IL-1alpha, IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10 and TNF-alpha) were detected by immunohistochemical methods in porcine lungs experimentally infected with Mh. Ten pigs were inoculated intranasally with Mh and killed in pairs weekly from 1- to 5-week post-inoculation (wpi). Three Mh-free pigs were taken as controls. Mh-antigen was shown in paraffin-wax-embedded tissues by immunohistochemistry in the luminal surface of bronchial and bronchiolar epithelial cells of all Mh-infected pigs. Significant increase in cytokine expression was detected on snap-frozen tissues from the bronchoalveolar exudate of the airways, mononuclear cells of the alveolar septa and macrophages and lymphocytes of the peribronchial and peribronchiolar lymphoid tissue, from 1 wpi onwards, compared to expression in non-pneumonic lungs. The main cytokines in the BALT of Mh-infected animals that showed an increase were IL-2, IL-4, IL-8, IL-10 and TNF-alpha. In the alveolar septa and bronchoalveolar exudate IL-1 (alpha and beta), IL-2, IL-4, IL-8 and IL-10 expression also increased in infected animals.
Insights
Porcine enzootic pneumonia (PEP) involves increased cytokine expression in the lungs following Mycoplasma hyopneumoniae (Mh) infection. This study tracked cytokine changes in infected pigs, revealing significant immune responses in various lung tissues.
Area of Science:
- Veterinary Pathology
- Immunology
- Swine Respiratory Diseases
Background:
- Porcine enzootic pneumonia (PEP) is a significant respiratory disease in swine.
- Understanding the immune response, particularly cytokine expression, is crucial for managing PEP.
- Mycoplasma hyopneumoniae (Mh) is the primary causative agent of PEP.
Purpose of the Study:
- To investigate the pathogenesis of PEP by examining cytokine expression in different pulmonary compartments.
- To detect the presence of Mycoplasma hyopneumoniae (Mh) and associated cytokines in experimentally infected porcine lungs.
- To quantify changes in proinflammatory and immunoregulatory cytokines during the course of Mh infection.
Main Methods:
- Experimental infection of pigs with Mycoplasma hyopneumoniae (Mh).
- Immunohistochemical detection of Mh-antigen and cytokines (IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, TNF-α) in lung tissues.
- Analysis of cytokine expression in various lung compartments (bronchoalveolar exudate, alveolar septa, lymphoid tissue) at weekly intervals post-inoculation.
Main Results:
- Mh-antigen was localized to the luminal surface of bronchial and bronchiolar epithelial cells in infected pigs.
- A significant increase in cytokine expression was observed from 1 week post-inoculation onwards in infected lungs compared to controls.
- Elevated levels of IL-2, IL-4, IL-8, IL-10, and TNF-α were noted in the Bronchoalveolar Lymphoid Tissue (BALT).
- Increased expression of IL-1 (α and β), IL-2, IL-4, IL-8, and IL-10 was detected in the alveolar septa and bronchoalveolar exudate.
Conclusions:
- Mycoplasma hyopneumoniae infection triggers a significant inflammatory and immunoregulatory cytokine response in porcine lungs.
- The study provides insights into the compartmentalized cytokine dynamics during PEP pathogenesis.
- These findings contribute to understanding the immune mechanisms underlying PEP and may inform future therapeutic strategies.
