20.500.12556/RUL-185398 Not all Group B Streptococci are alike macrophage responses reveal inflammatory and immune-evasive strains Background: Group B Streptococcus (GBS) remains a leading cause of neonatal sepsis and meningitis despite preventive strategies. Disease severity and clinical presentation vary widely and are influenced by strain-specific virulence traits. Macrophages are key innate immune sentinels during GBS infection; however, how genetically distinct clinical isolates differentially and dynamically reprogram macrophage inflammatory, immunoregulatory, metabolic, and cell death responses remains poorly understood. Methods: Human THP-1 macrophages were infected with 12 fully characterized clinical GBS isolates representing multiple serotypes, sequence types, clinical presentations, and neonatal gestational ages. Cytokine and chemokine production was quantified at 3 and 24 hours post-infection using LEGENDplex bead-based immunoassays. Caspase-1 activity was measured by bioluminescence, and expression of inflammatory, immunoregulatory, metabolic, and cell death–associated genes were assessed by RT-qPCR at 4 and 24 hours. Data were analyzed using appropriate statistical tests, and multidimensional responses were integrated using radar plot visualization. Results: Macrophage responses to GBS were highly isolate-specific and varied over time. Serotype Ia and Ib isolates triggered rapid inflammasome-associated activation with early IL-1β and IL-18 release and high caspase-1 activity, consistent with pyroptosis. In contrast, serotype II and especially hypervirulent serotype III isolates showed minimal early inflammasome activation but induced delayed immunoregulatory programs marked by elevated IL-10 and ACOD1 expression. Reciprocal analyses revealed an inverse relationship between ACOD1 and IL-1β and a positive association between ACOD1 and IL-10, indicating coordinated immunometabolic regulation. Serotype-specific glycolytic gene expression signatures appeared at later time points. Stratification by clinical metadata showed that isolates from preterm infants induced stronger early inflammatory responses. Conclusions: This study shows that GBS pathogenicity is not a uniform species-level trait but reflects isolate-specific abilities to reprogram macrophage immunity. By integrating temporal resolution with strain diversity, it provides a mechanistic framework linking macrophage immune trajectories to preterm birth–associated inflammation and heterogeneous outcomes in neonatal infections. clinical isolate heterogeneity Group B Streptococcus immune evasion inflammation macrophages preterm birth pyroptosis klinična heterogenost izolatov streptokok skupine B izogibanje imunskemu odzivu vnetje makrofagi prezgodnji porod piroptoza true false true Angleški jezik Slovenski jezik Članek v reviji 2026-08-03 10:52:34 2026-08-03 10:52:46 2026-08-04 04:01:19 0000-00-00 00:00:00 2026 0 0 21 str. art. 1819218 Vol. 16 Apr. 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 616-097:577 2235-2988 10.3389/fcimb.2026.1819218 275427843 RAZ_Janzic_Larisa_2026.pdf RAZ_Janzic_Larisa_2026.pdf 1 7FBFF2492BC19FA2CD1E80195B31C619 2ca3f00144757bd9bc029884b4ecb6f2bd99ce3177c13f47c490a80e30861e64 da5ce803-8f18-11f1-9b0d-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=243865 https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2026.1819218/full 1 6d1d30bc-8f18-11f1-9b0d-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=243864 Medicinska fakulteta 0 0 0