A new study recently revealed that aside from neutralizing, antibodies are distorting viruses too, thereby stopping them from properly attaching to and entering cells.
It is commonly known and understood that antibodies are neutralizing viruses by "latching onto their surfaces" and hindering them from infecting host cells, a SciTechDaily report specified.
According to associate professor of chemistry Ganesh Anand at Penn State, everybody thinks of antibodies as "binding to viruses" and stopping them from entering cells, essentially locking them down.
However, the professor continued, their study shows for the first time that antibodies may physically distort viruses, so they cannot properly attach to and infect host cells.
Effects of Antibodies on Dengue and Zika Viruses
In the study recently published in the Cell journal, Anand, together with his colleagues, investigated the interactions between a human monoclonal antibody or HMAb C10 and two viruses that cause disease, specifically Zika and dengue viruses.
The study authors used a combination of strategies, including cryogenic electronic microscopy or cryo-EM, to visualize the viruses and the hydrogen or deuterium exchange mass spectrometry (HDXMS) to understand their movement.
Anand explained that Cryo-EM engages flash-freezing a solution that contains molecules of interest and then targets them with electrons to produce several images of individual molecules in various orientations.
The professor added that such images are then integrated into one snapshot of what the molecule appears like. The approach offers much more precise images of molecules compared to other forms of microscopy.
To document the impacts of antibodies on dengue and Zika viruses, the team retrieved cryo-EM snapshots of the viruses under circumstances of rising antibody concentrations.
HDXMS Method Applied Along with HMAb C10 Antibodies
Similarly, the researchers applied HDXMS, a method in which molecules of interest, in this circumstance dengue and Zika viruses, along with HMAb C10 antibodies, are immersed in heavy water.
Anand explained heavy water has had its hydrogen atoms substituted with deuterium, the heavier isotopic cousin of hydrogen, Tech and Science Post said in a similar report.
The professor elaborated when a virus is submerged in heavy water, the hydrogen atoms on the surface of the virus interchange with deuterium.
One can then use mass spectrometry to gauge the virus's heaviness as a function of such a deuterium exchange. By doing this, the researchers observed that dengue, not the Zika virus, turned heavier with deuterium as more antibodies were added to the solution.
The study finding hints that for the dengue virus, the antibodies distort the virus and enable more deuterium to enter. It is as if the virus gets squished and more surface site becomes exposed where hydrogen can be substituted for deuterium.
On the contrary, the Zika virus did not turn heavier when placed in heavy water, proposing that its surface, while being fully occupied by antibodies, is not distorted.
The professor also said, by combining cryo-EM and HDXMS, the team was able to get a wide-ranging picture of what occurs when antibodies attach to the said two viruses.
He added that the more antibodies added, the more distorted the particles of the dengue virus, hinting about the so-called "stoichiometry," the association between the quantities of reactants and the products prior to, during, and following a chemical reaction, matters.
Related information about human antibodies against the dengue virus is shown on Mahidol World's YouTube video below:
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