Mechanical Softening of Vero Cells Induced by an Attenuated Measles Vaccine Virus

TL;DR

This study uses atomic force microscopy and confocal microscopy to quantify how an attenuated Measles Vaccine Virus causes mechanical softening and cytoskeletal reorganization in Vero cells within 24 hours.

Contribution

It introduces a combined AFM and confocal microscopy approach to characterize virus-induced biophysical and cytoskeletal changes in cells.

Findings

Infected cells showed a 35% decrease in Young's modulus indicating softening.

Viscoelastic properties such as relaxed modulus and viscosities were reduced upon infection.

Cytoskeletal reorganization, especially actin filament changes, was observed during infection.

Abstract

Quantitative characterization of biophysical alterations caused by viral infection remains at an early stage. In this study, we examined the mechanical response of Vero cells after exposure to an attenuated Measles Vaccine Virus using atomic force microscopy (AFM) in combination with confocal microscopy. AFM force distance measurements were conducted in the perinuclear region to evaluate changes in elastic and viscoelastic properties. Within 24 hours post infection, cells infected at a multiplicity of infection of 0.5 exhibited an approximately thirty five percent decrease in median of the Young modulus relative to uninfected controls, indicating substantial cellular softening. Corresponding shifts in viscoelastic behavior were observed, including reductions in the relaxed modulus and in viscosities (effects comparable to those induced by cytochalasin D mediated actin depolymerization). Confocal microscopy further revealed a dependent reorganization of the cytoskeleton upon infection, marked by altered F actin distribution and changes in filament architecture. These findings suggest that actin remodeling contributes to the altered viscoelastic properties observed during infection. This work proposes a straightforward and complementary approach for characterizing virus cell interactions by integrating AFM with confocal imaging.