Blockade Antibody Responses in Human Subjects Challenged with a New Snow Mountain Virus Inoculum

Area of Science:

• Virology
• Immunology
• Gastroenterology

Background:

• Noroviruses (NoVs) cause widespread gastroenteritis.
• Snow Mountain Virus (SMV) is a GII.2 prototype used in human challenge studies.
• Blockade antibodies are crucial for understanding NoV pathogenesis and vaccine efficacy, but SMV-specific data is limited.

Purpose of the Study:

• To characterize blockade antibodies in serum samples from individuals challenged with SMV.
• To examine the correlation between blockade antibody titers and SMV-specific IgG/IgA after challenge.
• To assess the association between HBGA blockade antibody concentrations and post-challenge days.

Main Methods:

• Secondary data analysis of serum samples from 33 SMV-inoculated subjects.
• Characterization of blockade antibodies, IgG, and IgA levels.
• Application of a linear mixed model to analyze antibody concentrations over time and by infection status.

Main Results:

• 75.7% of participants became infected after SMV challenge.
• Significant differences in blockade antibodies, IgA, and IgG were observed between infected and uninfected individuals from day 15 post-challenge.
• A significant correlation between IgG, IgA, and blockade antibodies was found in infected individuals by day 6 post-challenge.

Conclusions:

• Histo-blood group antigen (HBGA)-blockade antibody geometric mean titers (GMTs) are generated following SMV challenge.
• Blockade antibodies remain detectable up to 45 days post-challenge.
• The second-generation SMV inoculum demonstrates high effectiveness in eliciting an immune response.