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Updated: May 19, 2026
Induction of Leptomeningeal Cells Modification Via Intracisternal Injection
Published on: May 7, 2020
Group B Streptococcus interactions with human meningeal cells and astrocytes in vitro
Khalil Alkuwaity1, Alexander Taylor, John E Heckels
1Neisseria Research Group, Molecular Microbiology, Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Faculty of Medicine, Southampton General Hospital, Southampton, United Kingdom.
Background:
Streptococcus agalactiae (Group B Streptococcus, GBS) is a leading cause of life-threatening neonatal meningitis and survivors often suffer permanent neurological damage. How this organism interacts with the meninges and subsequently with astrocytes that constitute the underlying cortical glia limitans superficialis is not known.
Methodology/Principal Findings:
In this paper, we demonstrate dose-dependent adherence of GBS over time to human meningioma cells and fetal astrocytes in vitro, which was not influenced by expression of either β-haemolysin/cytolysin (β-h/c) toxin, different capsule serotypes or by absence of capsule (p>0.05). Internalization of GBS by both cell types was, however, a slow and an infrequent event (only 0.02-0.4% of associated bacteria were internalised by 9 h). Expression of β-h/c toxin did not play a role in invasion (p>0.05), whereas capsule expression lead to a reduction (p<0.05) in the numbers of intracellular bacteria recovered. GBS strains induced cytotoxicity as demonstrated by the measurement of lactate dehydrogenase (LDH) enzyme release by 9 h and by viable staining. Increasing levels of meningioma cell death correlated with bacterial growth and the phenotype of β-h/c toxin production, i.e. from weakly, to normo- to hyper-haemolytic. However, cytotoxicity was significantly greater (p<0.05) towards astrocytes, and infection with initial MOI≥0.003 induced 70-100% LDH release. By comparing wild-type (β-h/c(+)) and mutant (ΔcylE β-h/c(-)) strains and β-h/c toxin extracts and by using the surfactant dipalmitoylphosphatidylcholine in cytotoxicity inhibition experiments, β-h/c toxin was demonstrated as principally responsible for cell death.
Conclusions/Significance:
This study has described key events in the interactions of GBS with meningeal cells and astrocytes in vitro and a major virulence role for β-h/c toxin. Understanding the mechanisms involved will help to identify potential therapies for improving patient survival and for reducing the incidence and severity of neurological sequelae.
Insights
Streptococcus agalactiae (GBS) adheres to brain cells, causing damage. The β-haemolysin/cytolysin toxin is primarily responsible for GBS-induced cell death, offering potential therapeutic targets.
Area of Science:
- Neuroscience
- Microbiology
- Pathogenesis
Background:
- Streptococcus agalactiae (Group B Streptococcus, GBS) is a major cause of neonatal meningitis.
- Survivors of GBS meningitis often experience long-term neurological deficits.
- The interaction mechanisms between GBS and the central nervous system's protective layers (meninges) and astrocytes are poorly understood.
Purpose of the Study:
- To investigate the in vitro interactions between GBS and human meningeal cells and astrocytes.
- To determine the role of GBS virulence factors, including β-haemolysin/cytolysin (β-h/c) toxin and capsule, in these interactions.
- To elucidate the mechanisms underlying GBS-induced cytotoxicity in neural cells.
Main Methods:
- Dose-dependent adherence assays of GBS to human meningioma cells and fetal astrocytes.
- Assessment of GBS internalization by meningeal and astrocyte cell lines.
- Measurement of lactate dehydrogenase (LDH) release and viable cell staining to quantify cytotoxicity.
- Comparison of wild-type and mutant GBS strains (lacking β-h/c toxin) and use of purified toxin to identify responsible virulence factors.
Main Results:
- GBS demonstrated dose-dependent adherence to both meningioma cells and astrocytes, irrespective of β-h/c toxin or capsule expression.
- Bacterial internalization was infrequent, and capsule expression reduced intracellular bacterial numbers.
- GBS induced significant cytotoxicity in both cell types, with astrocytes being more vulnerable.
- The β-h/c toxin was identified as the principal factor responsible for GBS-induced cell death.
Conclusions:
- This study elucidates critical interactions between GBS and key neural cells in vitro.
- The β-h/c toxin plays a major role in GBS virulence and cytotoxicity against meningeal cells and astrocytes.
- Understanding these mechanisms can guide the development of novel therapies to improve outcomes for GBS meningitis patients.
Related Concept Videos
01:22Bacterial Meningitis I: Introduction
01:26Bacterial Meningitis II: Pathophysiology