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Published on: February 14, 2018
Distinct immunologic properties of Penicillium marneffei yeasts obtained from different in vitro growth conditions
Songsak Tongchusak1, Piyapong Pongtanalert, Supinya Pongsunk
1Department of Microbiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
Abstract:
A dimorphic fungus Penicillium marneffei is a causative agent of penicilliosis, a life-threatening disseminated disease in immunocompromised hosts predominantly found in southeast Asia and southern China. P. marneffei is the only known Penicillium that possesses a dimorphic characteristic. Since it is difficult to produce large amount of P. marneffei yeasts in vivo for experimentation purpose, yeast cells were produced in different in vitro conditions as alternatives. We interested in investigating the immunologic properties of yeast cells from different culture preparations. It was found that yeast cells obtained from brain heart infusion broth and Sabouraud dextrose broth did not resemble those resided in clinical specimens. A solution of 1% peptone, on the other hand, could induce a direct conidial transition into fission yeasts. Ability of yeast cells in each preparation to activate macrophages was determined by analyzing surface expression of CD40 and CD86 co-stimulatory molecules after two days of co-cultivation. Every P. marneffei yeast cell preparation demonstrated such ability. However, the ones from Sabouraud dextrose broth seemed to induce less phagocytosis. Additionally, although distinct antigenic profiles and lack of conformity in antigenic expression were observed among yeast cells from different culture conditions, most major immunogenic bands were present when Western analysis was performed using polyclonal antisera from penicilliosis patients. The results of the study raise attention on immunological and biochemical characteristics of P. marneffei yeasts if such preparations are to be used in future laboratory investigations.
Insights
Penicillium marneffei yeast cells cultured in vitro show varied immunologic properties. Peptone broth best mimics clinical yeast forms, impacting macrophage activation and antigen presentation for Penicilliosis research.
Area of Science:
- Mycology
- Immunology
- Infectious Diseases
Background:
- Penicillium marneffei causes life-threatening penicilliosis in immunocompromised individuals, prevalent in Southeast Asia.
- P. marneffei is unique among Penicillium species for its dimorphic nature, existing as mold and yeast.
- In vivo yeast production is challenging, necessitating in vitro alternatives for research.
Purpose of the Study:
- To investigate the immunologic properties of P. marneffei yeast cells cultured under different in vitro conditions.
- To determine the suitability of various culture media for generating yeast cells relevant to clinical Penicilliosis studies.
- To assess the impact of culture conditions on yeast morphology, macrophage activation, and antigenic profiles.
Main Methods:
- Culturing P. marneffei in brain heart infusion broth, Sabouraud dextrose broth, and 1% peptone solution.
- Analyzing yeast morphology and conidial transition.
- Co-cultivating yeast cells with macrophages and assessing CD40 and CD86 surface expression.
- Performing Western blot analysis using patient-derived polyclonal antisera to evaluate antigenic profiles.
Main Results:
- Yeast cells from 1% peptone broth exhibited direct conidial transition, resembling clinical forms.
- All preparations activated macrophages, but Sabouraud dextrose broth yielded reduced phagocytosis.
- Distinct antigenic profiles were observed across conditions, yet key immunogenic bands were present in most preparations.
- Morphological and immunological variations highlight the importance of culture method selection.
Conclusions:
- In vitro culture conditions significantly influence the immunological characteristics of P. marneffei yeast cells.
- 1% peptone broth is a promising medium for generating yeast forms relevant to Penicilliosis pathogenesis.
- Careful consideration of culture methods is crucial for accurate laboratory investigations of P. marneffei.
- Further research into P. marneffei immunobiology requires standardized yeast preparations.
