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Assessing Anti-fungal Activity of Isolated Alveolar Macrophages by Confocal Microscopy
Published on: July 9, 2014
Heat-killed Malassezia pachydermatis suspension modulates the activity of macrophages challenged with Encephalitozoon
Jéssica Feliciana Codeceira1, Anuska Marcelino Alvares-Saraiva1, Elizabeth Cristina Perez Hurtado1
1Programa de Patologia Ambiental e Experimental, Universidade Paulista-Unip, Rua Dr. Bacelar 902, São Paulo, SP CEP 05622-001, Brazil.
Abstract:
Phagocytic responses are critical for effective host defense against opportunistic fungal pathogens, such as Encephalitozoon cuniculi, an obligate intracellular fungus that causes emerging encephalitozoonosis in humans and other animals. Malassezia has immunomodulatory effects and can modulate the production of pro- and anti-inflammatory cytokines via keratinocytes and human monocytes. In this study, we evaluated the modulatory effects of heat-killed Malassezia pachydermatis suspension on macrophages challenged with Encephalitozoon cuniculi. Macrophages were treated with heat-killed M. pachydermatis suspension before being infected with spores of E. cuniculi. The cultures were stained with calcofluor, and the spores, internalized or not, were counted to determine their phagocytic capacity and index (PC and PI, respectively). Microbicidal and phagocytic activities were evaluated by transmission electron microscopy (TEM). The untreated macrophages had higher PC and PI and number of phagocytosed spores than treated macrophages. However, TEM revealed that treated macrophages had higher microbicidal activity because there were few spores in different degrees of degeneration and amorphous materials in the phagocytic vacuoles. Macrophages treated with heat-killed M. pachydermatis suspension had lower PC and PI and incipient presence of E. cuniculi in phagosomes. Treated macrophages had a mixed pattern of cytokine release with Th1, Th2, and Th17 profiles, with emphasis on interleukin (IL)-10, IL-4, IL-17, IL-6, and interferon (IFN)-γ secretion, and particularly high production of anti-inflammatory cytokines. Our results suggest that treatment with heat-killed M. pachydermatis suspension increases the release of cytokines and decreases the phagocytic activity of macrophages challenged with E. cuniculi.
Insights
Heat-killed Malassezia pachydermatis suspension enhances macrophage microbicidal activity against Encephalitozoon cuniculi but reduces phagocytic capacity, altering cytokine profiles.
Area of Science:
- Immunology
- Mycology
- Cell Biology
Background:
- Phagocytic responses are crucial for host defense against fungal pathogens like Encephalitozoon cuniculi.
- Malassezia species possess immunomodulatory properties, influencing cytokine production in immune cells.
Purpose of the Study:
- To investigate the effects of heat-killed Malassezia pachydermatis on macrophages challenged with Encephalitozoon cuniculi.
- To assess the impact on phagocytic activity, microbicidal capacity, and cytokine release.
Main Methods:
- Macrophages were treated with heat-killed M. pachydermatis before infection with E. cuniculi spores.
- Phagocytic capacity and index were quantified using calcofluor staining.
- Microbicidal activity and spore degradation were examined via transmission electron microscopy (TEM).
- Cytokine profiles (Th1, Th2, Th17) were analyzed based on secreted interleukins and interferons.
Main Results:
- Heat-killed M. pachydermatis treatment reduced macrophage phagocytic capacity and index.
- TEM revealed enhanced microbicidal activity in treated macrophages, with degenerated E. cuniculi spores observed.
- Treated macrophages exhibited a mixed cytokine release pattern, with a notable increase in anti-inflammatory cytokines like IL-10 and IL-4.
Conclusions:
- Heat-killed Malassezia pachydermatis modulates macrophage responses to Encephalitozoon cuniculi.
- While phagocytosis decreases, microbicidal activity is enhanced, alongside a shift towards anti-inflammatory cytokine production.
