FIG 4.

Analysis of differentially expressed genes in response to S. pneumoniae infection in PMNs from old WT mice. (A) Volcano plot representing differential gene expression (FDR, <0.05) in response to ex vivo infection with S. pneumoniae TIGR4 compared to a mock-infected control in PMNs isolated from the bone marrow of old WT mice. Genes marked in green represent significantly downregulated DEGs (log₂FC ≤ −1.0; FDR < 0.05), and genes marked in red represent significantly upregulated DEGs (log₂FC ≥ 1.0; FDR < 0.05). (B and C) Gene ontology (GO) enrichment analysis using DAVID, indicating the top 10 significant (P ≤ 0.05) biological process (BP), molecular function (MF), cellular component (CC), and KEGG pathway terms for significantly downregulated DEGs (B) and significantly upregulated DEGs (C).