Effect of endotoxin on cells and on their response to infection by polioviruses

Area of Science:

• Microbiology
• Cell Biology
• Virology

Background:

• Lipopolysaccharide (endotoxin) is a component of Gram-negative bacteria.
• Endotoxin can modulate cellular responses and immune functions.
• The interaction between endotoxin and viral infections in cell cultures requires further elucidation.

Purpose of the Study:

• To investigate the cytotoxic effects of endotoxin on various human and mouse cell lines.
• To determine the impact of endotoxin on cellular susceptibility and response to poliovirus infection.
• To explore if endotoxin can induce latent poliovirus infections.

Main Methods:

• Exposure of HeLa-S3, HeLa-Gey, Chang-liver, Maben, and L strain mouse fibroblasts to varying concentrations of endotoxin.
• Assessment of cell viability, agglutination, and nuclear changes following endotoxin treatment.
• Infection of endotoxin-treated cell cultures with cytopathic and noncytopathic poliovirus strains.
• Quantification of poliovirus yields and plating efficiency.

Main Results:

• Differential sensitivity of cell strains to endotoxin, with Chang-liver cells being most sensitive and Maben cells most resistant.
• Cytotoxic effects on L strain mouse fibroblasts at concentrations above 100 mug/ml, characterized by nuclear changes, not lysis.
• Endotoxin slightly accelerated cytopathic effects of cytopathic poliovirus but did not induce responses to noncytopathic poliovirus.
• Endotoxin marginally reduced poliovirus yields but did not alter virus plating efficiency.

Conclusions:

• Endotoxin exhibits dose-dependent cytotoxic and agglutinative effects on specific cell lines.
• Endotoxin can modulate the cellular response to certain viral infections but does not induce latent viral activity.
• The findings highlight the complex interplay between bacterial endotoxins and viral pathogenesis in cell culture models.