Role of cell surface proteins and toll-like receptors in the pathogenesis of Streptococcus pneumoniae

Objective(s): Pneumococcal cell wall (PCW) is an inflammatory component in Streptococcus pneumoniae. The cell surface proteins and the toll-like receptors (TLR) signaling response were investigated in the human lung epithelial (A۵۴۹) cells inoculated with PCW of different serotypes.Materials and Methods: The presence of genes encoding these proteins was determined using polymerase chain reaction (PCR). The structure of the cell walls was analyzed by proton nuclear magnetic resonance (۱H NMR). The A۵۴۹ cell line was challenged with PCW extracts of different serotypes. RNA from the infected host cells was extracted and tested against a total of ۸۴ genes associated with TLR signaling pathways (TLR ۱-۶ and ۱۰) using RT۲ Profiler PCR Array.Results: Cell surface proteins; ply, lytA, nanA, nanB, and cbpD genes were present in all serotypes. The distribution and structure of surface protein genes suggest behavioral changes in the molecules, contributing to the resilience of the strains to antibiotic treatment.Conclusion: TLR۲ showed the highest expression, while serotypes ۱, ۳, and ۵ induced higher TNFα and IL-۱α, suggesting to be more immunogenic than the other strains tested.

Keywords:

A۵۴۹ cell line , Cell wall , Serotype , Streptococcus pneumoniae , Surface proteins , Toll-like receptors