Antigenic relationship between Candida parapsilosis and Candida albicans serotype B

Area of Science:

• Immunology
• Microbiology
• Glycochemistry

Background:

• Candida species are significant human pathogens.
• Antigenic relationships between Candida species are crucial for understanding host immune responses and developing diagnostics.
• Specific antigenic factors, like 13 and 13b, differentiate Candida parapsilosis and Candida albicans serotype B.

Purpose of the Study:

• To investigate the antigenic relationship between Candida parapsilosis and Candida albicans serotype B.
• To determine the chemical structure of oligosaccharides derived from their cell-wall mannans.
• To elucidate the role of these oligosaccharides in specific antigenic factors.

Main Methods:

• Acetolysis of cell-wall mannans from C. albicans serotype B and C. parapsilosis.
• Structural elucidation of oligosaccharides using 1H-nuclear magnetic resonance (NMR) spectroscopy, methylation analysis, and partial acid hydrolysis.
• Inhibition assays of precipitin and agglutination reactions using oligosaccharides and specific antisera.

Main Results:

• The hexasaccharide (M6) structure derived from both C. albicans serotype B and C. parapsilosis mannans was determined to be identical.
• M6 was identified as the most effective inhibitor in both homologous and heterologous precipitin and agglutination reactions.
• While M6 structures are identical, the overall mannan structures differ, and M6 is more abundant in C. parapsilosis.

Conclusions:

• The identical chemical structure of M6 in C. parapsilosis and C. albicans serotype B suggests it is a conserved epitope.
• M6 is likely involved in the specificity of antigenic factors 13 and 13b.
• The higher concentration of M6 in C. parapsilosis may contribute to the induction of species-specific antibodies.