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Updated: Aug 9, 2026
Measuring Bacterial Load and Immune Responses in Mice Infected with Listeria monocytogenes
Published on: August 9, 2011
Infection with Listeria monocytogenes impairs sialic acid addition to host cell glycoproteins
M S Villanueva1, C J Beckers, E G Pamer
1Department of Internal Medicine, Yale University Medical School, New Haven, Connecticut 06520-8022.
Abstract:
Listeria monocytogenes is a facultative intracellular bacterium that causes severe disease in neonates and immunocompromised adults. Although entry, multiplication, and locomotion of Listeria in the cytosol of infected cells are well described, the impact of such infection on the host cell is unknown. In this report, we investigate the effect of L. monocytogenes infection on MHC class I synthesis, processing, and intracellular trafficking. We show that L. monocytogenes infection interferes with normal processing of N-linked oligosaccharides on the major histocompatibility complex (MHC) class I heavy chain molecule, H-2Kd, resulting in a reduced sialic acid content. The glycosylation defect is more pronounced as the infection progresses and results from interference with the addition of sialic acid rather than its removal by a neuraminidase. The effect is found in two different cell lines and is not limited to MHC class I molecules since CD45, a surface glycoprotein, and LGP120, a lysosomal glycoprotein, are similarly affected by L. monocytogenes infection. The glycosylation defect is specific for infection by L. monocytogenes since neither Trypanosoma cruzi nor Yersinia enterocolitica, two other intracellular pathogens, reproduces the effect. The resultant hyposialylation of H-2Kd does not impair its surface expression in infected cells. Diminished sialic acid content of surface glycoproteins may enhance host-defense by increasing susceptibility to lysis and promoting clearance of Listeria-infected cells.
Insights
Listeria monocytogenes infection alters host cell glycosylation, specifically reducing sialic acid on MHC class I molecules. This hyposialylation may enhance host defense against infected cells.
Area of Science:
- Microbiology
- Immunology
- Cell Biology
Background:
- Listeria monocytogenes is a significant intracellular pathogen causing severe illness in vulnerable populations.
- While Listeria's intracellular mechanisms are known, its impact on host cell processes remains unclear.
Purpose of the Study:
- To investigate the effects of Listeria monocytogenes infection on host cell major histocompatibility complex (MHC) class I synthesis, processing, and trafficking.
- To determine if L. monocytogenes infection impacts glycosylation of MHC class I molecules.
Main Methods:
- Analysis of N-linked oligosaccharide processing on the H-2Kd heavy chain of MHC class I molecules in infected cells.
- Assessment of sialic acid content and glycosylation patterns of surface and lysosomal glycoproteins (CD45, LGP120).
- Comparative analysis using other intracellular pathogens (Trypanosoma cruzi, Yersinia enterocolitica).
Main Results:
- L. monocytogenes infection disrupts N-linked oligosaccharide processing, leading to reduced sialic acid content (hyposialylation) on the H-2Kd molecule.
- This glycosylation defect is progressive and specific to L. monocytogenes infection, affecting other glycoproteins like CD45 and LGP120.
- Hyposialylation of H-2Kd does not impede its surface expression.
Conclusions:
- L. monocytogenes infection causes a specific host cell glycosylation defect, characterized by hyposialylation of MHC class I and other glycoproteins.
- This defect may represent a host-defense mechanism, potentially increasing the susceptibility of infected cells to immune clearance.
