Human Norovirus Triggers Primary B Cell Immune Activation In Vitro

Area of Science:

• Immunology
• Virology
• Gastroenterology

Background:

• Human norovirus (HNoV) causes significant global health and economic burdens, with individuals experiencing multiple infections due to a lack of lasting immunity.
• Understanding HNoV's interaction with the immune system, particularly B cells, is crucial for developing effective interventions and vaccines.

Purpose of the Study:

• To investigate the susceptibility of primary human B cells to HNoV infection.
• To determine the functional impact of HNoV infection on B cell subsets and activation.
• To explore the role of the HNoV NS1 protein in modulating B cell responses.

Main Methods:

• Primary human B cells were isolated from blood, spleen, and lymph node specimens.
• Cells were infected with HNoV and analyzed for viral RNA yield using RT-qPCR.
• B cell subsets were characterized by flow cytometry, and responses to HNoV virus-like particles and NS1 protein were assessed.

Main Results:

• HNoV RNA yield increased significantly in 50-60% of primary B cell donors.
• Infection altered the distribution of B cell subsets.
• The NS1 protein induced B cell activation and metabolic changes in vitro.

Conclusions:

• Primary human B cells are susceptible to HNoV infection.
• The HNoV NS1 protein can modulate B cell activation and metabolism, suggesting a mechanism for immune evasion and impacting pathogenesis.
• These findings have implications for understanding HNoV's recurrent nature and developing therapeutic strategies.