Not all Group B Streptococci are alikeJanžič, Larisa (Avtor) Sršen, Lucija (Avtor) Petrin, Sara (Avtor) Ihan, Alojz (Avtor) Kopitar, Andreja Nataša (Avtor) clinical isolate heterogeneityGroup B Streptococcusimmune evasioninflammationmacrophagespreterm birthpyroptosisBackground: 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.20262026-08-03 10:52:34Članek v reviji185398sl