Group B Streptococcus (GBS) is one of the most common causes of neonatal illness and death worldwide. Pregnant women, the elderly, and immunocompromised individuals are also severely affected by GBS. The transition from asymptomatic colonization to invasive disease is not yet fully understood. In our study, we used flow cytometry to
analyze the production of cytokines after stimulation of macrophages to investigate the effects of different GBS strains on the severity of disease progression. We found
differences in the production of inflammatory cytokines, regulatory cytokines and chemokines 3 and 24 hours after macrophage stimulation, as well as differences in
cytokine production between different GBS serotypes. We observed the influence of different cytotoxic GBS strains on the profile of cytokine production. Based on the
measurements of IL-1ß and IL-18, we hypothesize that certain GBS strains induce pyroptosis in stimulated macrophages. By analyzing IL-12 production, we found differences in activation of the secondary immune response between GBS strains. In the case of the hypervirulent sequence type ST-17, we observed lower production of inflammatory cytokines and increased production of the regulatory cytokine IL-10 at
the onset of infection, which we related to its ability to evade the immune system and cause invasive infections.
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