Objective: To investigate whether Candida albicans-native phospholipomannan (PLM) induce an inflammation response through Toll-like receptor(TLRé2 in human acute monocytic leukemia cell line (THP-1) cells.
Methods: Human THP-1 monocytes were challenged with PLM in vitro. The mRNA expressions of TLR2, TLR4, proinflammatory cytokine [interleukin(IL)-6], and chemokine (IL-8) were assayed by real time reverse transcription polymerase chain reaction. The secretions of IL-6 and IL-8 were measured by enzyme-linked immunosorbent assay. The expression of TLR2 was analyzed with Western blot.
Results: PLM increased the mRNA expressions and secretions of proinflammatory cytokines (IL-6) and chemokines (IL-8) in THP-1 cells (all P=0.0000). PLM up-regulated the mRNA and protein levels of TLR2 (P=0.0000), whereas the mRNA level of TLR4 was not altered. PLM hydrolyzed with β-D-mannoside manno hydrolase failed to induce gene and protein expressions of TLR2, IL-6, and IL-8. Anti-TLRS-neutralizing antibody blocked the PLM-induced secretions of IL-6 and IL-8 in THP-1 cells (P = 0.0003, P = 0.0010).
Conclusion: Canidada albicans-native PLM may contribute to the inflammatory responses during Candida infection in a TLR2-dependent manner.