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Antigenic relationship of Penicillium marneffei to P. primulinum
A S Sekhon1, A K Garg, A A Padhye
1National Reference Center for Human Mycotic Diseases, University of Alberta, Edmonton, Canada.
Abstract:
Penicillium marneffei (ATCC 24100) was first isolated from a naturally acquired human infection in the U.S.A. by DiSalvo et al. in 1973. In 1979, this isolate was studied by Pitt who reidentified it as Penicillium primulinum. This prompted us to examine the antigenic relationship between P. marneffei and P. primulinum by comparing their exoantigens. The antigenic relationships of 11 isolates, including the type strains of P. marneffei and P. primulinum, were examined. Each exoantigen extract was tested simultaneously against rabbit anti-P. marneffei and P. primulinum antisera in the presence of the appropriate reference antigens. All eight isolates of P. marneffei, including ATCC 24100, produced two to four specific precipitin lines against their homologous antiserum. However, four of the eight extracts cross-reacted with unabsorbed antiserum to P. primulinum. The P. primulinum extracts contained specific exoantigens which only reacted with the anti-P. primulinum antiserum. Non-specific cross-reactions were eliminated by absorption procedures. On the basis of the specific exoantigens produced by both species, P. marneffei and P. primulinum were found to be antigenically distinct. Isolate ATCC 24100 was shown to be closely related to the other P. marneffei isolates and distinct from P. primulinum. Our results confirm the original identification of ATCC 24100 as P. marneffei and not P. primulinum as Pitt had concluded.
Insights
Penicillium marneffei and Penicillium primulinum are antigenically distinct species. This study confirms isolate ATCC 24100 is Penicillium marneffei, not Penicillium primulinum, based on exoantigen analysis.
Area of Science:
- Medical Mycology
- Immunology
Background:
- Penicillium marneffei (ATCC 24100) was initially identified from a human infection.
- A subsequent study reidentified this isolate as Penicillium primulinum, creating taxonomic uncertainty.
Purpose of the Study:
- To clarify the taxonomic status of Penicillium marneffei (ATCC 24100) by comparing its exoantigens with Penicillium primulinum.
- To determine the antigenic relationship between P. marneffei and P. primulinum isolates.
Main Methods:
- Exoantigen extracts from 11 fungal isolates, including type strains, were prepared.
- Rabbit antisera against P. marneffei and P. primulinum were used in immunodiffusion assays.
- Absorption procedures were employed to remove non-specific cross-reactions.
Main Results:
- All P. marneffei isolates, including ATCC 24100, showed specific precipitin lines against homologous antiserum.
- P. primulinum extracts contained unique exoantigens, distinct from P. marneffei.
- Isolate ATCC 24100 demonstrated antigenic similarity to other P. marneffei isolates.
Conclusions:
- Penicillium marneffei and Penicillium primulinum are antigenically distinct species.
- The original identification of ATCC 24100 as P. marneffei is confirmed.
- The reidentification of ATCC 24100 as P. primulinum was inaccurate.