Structural analysis of influenza vaccine virus-like particles reveals a multicomponent organization

Abstract

Influenza virus continues to be a major health problem due to the continually changing immunodominant head regions of the major surface glycoprotein, hemagglutinin (HA). However, some emerging vaccine platforms designed by biotechnology efforts, such as recombinant influenza virus-like particles (VLPs) have been shown to elicit protective antibodies to antigenically different influenza viruses. Here, using biochemical analyses and cryo-electron microscopy methods coupled to image analysis, we report the composition and 3D structural organization of influenza VLPs of the 1918 pandemic influenza virus. HA molecules were uniformly distributed on the VLP surfaces and the conformation of HA was in a prefusion state. Moreover, HA could be bound by antibody targeting conserved epitopes in the stem region of HA. Taken together, our analysis suggests structural parameters that may be important for VLP biotechnology such as a multi-component organization with (i) an outer component consisting of prefusion HA spikes on the surfaces, (ii) a VLP membrane with HA distribution permitting stem epitope display, and (iii) internal structural components.

Synthesis and Assembly of Hepatitis B Virus-Like Particles in a Pichia pastoris Cell-Free System

“…It is possible that some of the CIP protein remains bound to HBc during the purification process or it may become encapsulated as the VLP forms, leading to its persistence. For example, it was recently observed that an influenza VLP contained an internal component density postulated to be encapsulated cellular components (McCraw et al, 2018). The CIP protein is also visible in the negative control sample containing CIP (Lane 4), along with other higher molecular weight contaminants.…”

Advanced Nanobiomedical Approaches to Combat Coronavirus Disease of 2019

“…[ 45 ] The influenza viruses present another enduring viral challenge because hemagglutinin, the glycoprotein responsible for entry, rapidly mutates. [ 60 ] As a result, new influenza vaccines must be made each year to maintain protection from the new changes in hemagglutinin conformation. Even then, vaccine production lags behind influenza virus changes.…”

“…[61] It has been suggested that using multistructural VLPs as vaccines, instead of the classic influenza vaccine method using embryonated chicken eggs, could produce immune responses that would defend against the different forms of influenza. [34,60,62,63] More investigation is necessary, but influenza VLPs have the potential to save time and labor spent continuously developing subtype-and strain-specific influenza vaccines. Even as VLPs are used to address challenges that plagued for centuries, they are also being considered as novel infectious diseases emerge.…”

Towards a Quantitative Single Particle Characterization by Super Resolution Microscopy: From Virus Structures to Antivirals Design

“…Lastly, from the first image of a virus obtained in 1938and 1939(von Borries et al, 1938Ruska et al, 1939), EM, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and cryo-electron microscopy (cryo-EM) have been the main microscopy techniques used to study and characterize viruses (Leser and Lamb, 2017), virus-like particles (McCraw et al, 2018), viral glycoproteins (Wu and Wilson, 2020) and viral inhibitors (Liu et al, 2020;Zhou et al, 2020). However, traditional morphological studies require the negative staining of the sample under extreme conditions.…”