Characterization of Lassa virus cell entry and neutralization with Lassa virus pseudoparticles

Area of Science:

• Virology
• Immunology
• Cell Biology

Background:

• The cell entry mechanisms and humoral immune responses of Lassa virus (LV), a dangerous Old World arenavirus, are not fully understood.
• Lassa virus pseudoparticles (LVpp) serve as a valuable surrogate system for studying LV cell entry under less stringent biosafety conditions.

Purpose of the Study:

• To characterize Lassa virus (LV) cell entry pathways and glycoprotein fusion pH requirements using LV pseudoparticles (LVpp).
• To establish LVpp as a tool for quantifying neutralizing antibodies and studying the humoral immune response to LV infections.

Main Methods:

• Generation and characterization of highly infectious Lassa virus pseudoparticles (LVpp).
• Assessment of LVpp cell entry via endocytic vesicles.
• Determination of optimal pH for LV glycoprotein-mediated fusion and viral resistance to low pH.
• Quantification of neutralizing antibodies in human and animal sera using LVpp.

Main Results:

• LVpp exhibit high infectivity, comparable to vesicular stomatitis virus G protein pseudoparticles.
• LVpp utilize endocytic pathways for cell entry, with fusion optimally activated at unusually low pH (3-4.5).
• Wild-type LV and LVpp demonstrate significant resistance to low pH exposure.
• LVpp enable rapid and quantifiable detection of Lassa virus-neutralizing antibodies.

Conclusions:

• LVpp are a robust and safe tool for investigating Lassa virus cell entry and the pH-dependent fusion mechanisms of its glycoproteins.
• The unique low-pH fusion requirement and resistance to acid exposure are key characteristics of Lassa virus.
• LVpp facilitate the study of humoral immunity against Lassa virus, aiding in vaccine development and diagnostics.