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Updated: Sep 19, 2025
In situ TEM of Biological Assemblies in Liquid
Published on: December 30, 2013
Microfluidics combined with electron microscopy for rapid and high-throughput mapping of antibody-viral glycoprotein
Leigh M Sewall1, Rebeca de Paiva Froes Rocha1,2, Grace Gibson1
1Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA.
Abstract:
Understanding the mechanistic interplay between antibodies and invading pathogens is essential for vaccine development. Current methods are labour and time intensive and limited by sample preparation bottlenecks. Here we present microfluidic electron microscopy-based polyclonal epitope mapping (mEM), which combines microfluidics with single-particle electron microscopy for the structural characterization of immune complexes using small volumes of sera (<4 µl). First, we used mEM to map polyclonal antibodies present in sera from infected and vaccinated individuals against five viral glycoproteins using negative-stain electron microscopy. The mEM detected a greater number of epitopes compared with conventional polyclonal epitope structural mapping methods. Second, we used mEM and cryo-electron microscopy to characterize two coronavirus spikes and one HA glycoprotein with and without polyclonal antibodies. Finally, we mapped individual antibody responses over time in mice vaccinated with human immunodeficiency virus envelope N332-GT5. mEM enables the rapid, high-throughput mapping of antibodies targeting a broad range of glycoproteins, facilitating a better understanding of infection and guiding structure-based vaccine design.
Insights
Microfluidic electron microscopy (mEM) rapidly maps antibody epitopes on pathogens. This new method accelerates vaccine development by providing structural insights into immune responses with minimal sample volume.
Area of Science:
- Structural biology
- Immunology
- Vaccine development
Background:
- Understanding antibody-pathogen interactions is crucial for effective vaccine design.
- Existing epitope mapping methods are time-consuming and require extensive sample preparation.
- There is a need for high-throughput, sensitive techniques to analyze polyclonal antibody responses.
Purpose of the Study:
- To introduce and validate microfluidic electron microscopy-based polyclonal epitope mapping (mEM) for structural characterization of immune complexes.
- To demonstrate mEM's capability in mapping polyclonal antibody epitopes against viral glycoproteins.
- To showcase mEM's utility in analyzing antibody responses for vaccine design.
Main Methods:
- Integration of microfluidics with single-particle electron microscopy (negative-stain and cryo-EM).
- Utilized small serum volumes (<4 µl) for immune complex analysis.
- Applied mEM to viral glycoproteins, coronavirus spikes, and HA glycoproteins, with and without antibodies.
Main Results:
- mEM identified a higher number of epitopes compared to conventional methods.
- Characterized structural changes in viral glycoproteins upon polyclonal antibody binding.
- Successfully mapped individual antibody responses over time in a mouse model.
Conclusions:
- mEM offers a rapid, high-throughput platform for mapping antibody targets on diverse glycoproteins.
- This technique enhances understanding of infection dynamics and guides structure-based vaccine design.
- mEM significantly advances the field of immunogenomics and structural vaccinology.
