Expression Pattern of the Pneumocystis jirovecii Major Surface Glycoprotein Superfamily in Patients with Pneumonia

Area of Science:

• Medical Mycology
• Molecular Biology
• Immunology

Background:

• Pneumocystis jirovecii, an opportunistic human pathogen, possesses six families of major surface glycoproteins (MSGs).
• MSGs are critical for P. jirovecii's antigenic variation and host cell adhesion.
• Gene organization implies simultaneous expression of non-Family I MSGs and single Family I MSG expression per cell.

Purpose of the Study:

• To investigate the expression patterns of P. jirovecii major surface glycoproteins (MSGs).
• To determine the diversity of expressed MSG isoforms within clinical samples.

Main Methods:

• RNA sequencing of clinical samples.
• Utilized specific weighted profiles for read sorting.
• Employed single-nucleotide variant calling to assess gene diversity.

Main Results:

• Simultaneous expression of multiple MSG isoforms from at least four families was observed.
• Confirmed co-expression of Family I MSG isoforms in wet laboratory experiments.
• Demonstrated significant diversity in expressed genes within P. jirovecii populations.

Conclusions:

• P. jirovecii populations comprise individual cells with distinct surface protein profiles.
• These findings advance the understanding of P. jirovecii's unique antigenic variation mechanisms.
• The diverse surface properties likely play a role in host-pathogen interactions.