Saps1-3 Antigens in <i>Candida albicans</i>: Differential Modulation Following Exposure to Soluble Proteins, Mammalian Cells, and Infection in Mice

• Main Authors: Pedro F. Barbosa (Author), Diego S. Gonçalves (Author), Lívia S. Ramos (Author), Thaís P. Mello (Author), Lys A. Braga-Silva (Author), Marcia R. Pinto (Author), Carlos P. Taborda (Author), Marta H. Branquinha (Author), André L. S. Santos (Author)
• Format: Book
• Published: MDPI AG, 2024-06-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

The secreted aspartic peptidases (Saps) of <i>Candida albicans</i> play crucial roles in various steps of fungal-host interactions. Using a flow cytometry approach, this study investigated the expression of Saps1-3 antigens after (i) incubation with soluble proteins, (ii) interaction with mammalian cells, and (iii) infection in immunosuppressed BALB/c mice. Supplementation strategies involving increasing concentrations of bovine serum albumin (BSA) added to yeast carbon base (YCB) medium as the sole nitrogenous source revealed a positive and significant correlation between BSA concentration and both the growth rate and the percentage of fluorescent cells (%FC) labeled with anti-Saps1-3 antibodies. Supplementing the YCB medium with various soluble proteins significantly modulated the expression of Saps1-3 antigens in <i>C. albicans</i>. Specifically, immunoglobulin G, gelatin, and total bovine/human sera significantly reduced the %FC, while laminin, human serum albumin, fibrinogen, hemoglobin, and mucin considerably increased the %FC compared to BSA. Furthermore, co-cultivating <i>C. albicans</i> yeasts with either live epithelial or macrophage cells induced the expression of Saps1-3 antigens in 78% (mean fluorescence intensity [MFI] = 152.1) and 82.7% (MFI = 178.2) of the yeast cells, respectively, compared to BSA, which resulted in 29.3% fluorescent cells (MFI = 50.9). Lastly, the yeasts recovered from the kidneys of infected immunosuppressed mice demonstrated a 4.8-fold increase in the production of Saps1-3 antigens (MFI = 246.6) compared to BSA, with 95.5% of yeasts labeled with anti-Saps1-3 antibodies. Altogether, these results demonstrated the positive modulation of Saps' expression in <i>C. albicans</i> by various key host proteinaceous components, as well as by in vitro and in vivo host challenges.

Item Description

10.3390/idr16040043
2036-7449