High-throughput characterization of human fibroblast responses to a panel of Staphylococcus aureus antigen proteins using Olink proteomics

Background Staphylococcus aureus is a major human pathogen that can elicit immune-inflammatory responses and infections, largely driven by its broad repertoire of antigenic proteins. Understanding these factors is valuable for elucidating mechanisms of infection. Methods Fifty-two recombinant S. aureus antigen proteins were individually applied to cultured human dermal fibroblasts (HDFs). Following antigen stimulation of confluent HDFs (52 antigen + 44 controls; in three replicate plates), host protein responses were quantified using Olink inflammation, cardiovascular II, and III proteomic platforms. Data were analyzed using unsupervised clustering, differential expression analysis, and correlation network modeling to identify patterns of immune-inflammatory signals. Results Unsupervised analysis identified three distinct host-response clusters, with concordant separation observed across hierarchical clustering (Ward.D2) and t-SNE projection. These clusters can be broadly defined as a cytotoxic/inflammatory antigen cluster (Cluster_1), enriched for key virulence factors (e.g., HlgA, Atl.1, SasG.2) and characterized by marked upregulation of inflammatory mediators (including IL-6, IL-8, CXCL1, and CCL3). An immune modulation/surface protein cluster (Cluster_2), comprising adhesins and immune-evasion proteins (e.g., Chp, SSL11, Atl.2) associated with selective upregulation of AXIN1, IL-33, and DECR1. A small outlier antigen cluster (Cluster_4), consisting of LuKE and SdrD.1, which did not exhibit a clearly defined host-response profile. Differential expression analysis identified 12 core host proteins—including COL1A1, CXCL1, CXCL16, DLK-1, GLO1, IGFBP-1, IL33, IL6, IL8, MCP-1, TNF, and TRAIL-R2—with consistent and significant changes across clusters (FDR-adjusted p < 0.01). Conclusions This preliminary study suggests that S. aureus antigen proteins trigger a coordinated immune-inflammatory cascade in HDFs.