Influenza-host Interactions in 3D Specimens

Greb, Christoph

March 04, 2021

Influenza-host Interactions in 3D Specimens

The THUNDER Imager 3D Cell Culture visualizes an influenza (red) infected primary porcine lung epithelial grown in a multilayer of about 60 µm. The top layer shows cilia (green), which are responsible for mucus transport. Nuclei are stained in blue. Raw image vs. Large Volume Computational Clearing. Courtesy of Dr. Stefan Finke, Friedrich-Loeffler-Institute, Riems (Germany). THUNDER_Imager_3D_Cell_Culture_Infectious-Disease_Influenza.jpg

Stefan Finke studies virus-host interactions. It turns out that the ways the virus and host interact are different when comparing results from classical laboratory monolayer cell lines and “close to in vivo” infection models. For this reason, he switched to 3D cell culture systems which are a mixture of ciliated epithelial cells and mucus producing cells creating a multiple cell layer about 60 µm thick. This system is comparable to lungs with the apical side exposed to air, based on the respiratory tract origin of these cells.

THUNDER Imagers overcome the challenge widefield microscopes have with thicker samples

The questions which should be answered concerning this new experimental system are: i) if the infection kinetic differs from standard cell cultures and ii) which cells are infected: ciliated or non-ciliated? Moreover, it should also be investigated whether there is any major damage done to these cells or not.

The challenge for widefield microscopy when imaging thicker samples are out-of-focus signals which are perceived as background haze. THUNDER Imagers utilize computational clearing to overcome this problem.

“In particular with large fixed samples, where conventional widefield microscopy suffers from scattering, use of intense light, etc., the THUNDER technology enables us to produce sharp images in a reasonable time frame.”

Time is the main benefit

Time is the main benefit for Stefan Finke’s laboratory, because the THUNDER Imager enables his lab researchers to do fast sample scans, use multiple-well-plates, and screen samples quickly.

Another specimen used in his lab are tissue slices of 1 mm or more thickness from infected animals. After immunostaining, the tissues are examined with the microscope: 3D image stacks are done to screen all the different samples for those that are virus positive. Because the background haze, which occurs when imaging these thick tissues even after optical clearing, is eliminated with the THUNDER Imager , his lab researchers can acquire fast overviews of their samples. Afterwards, they can go to the next step and use a confocal or light sheet microscope to do high-resolution 3D imaging.

“The THUNDER system is very helpful because of the sharpness of the images, the speed, and also the eases to acquire images.”

Efficiency for more productivity

Efficiency of the THUNDER Imager is another advantage for the Finke lab, as the researchers have limited time to acquire the important image data. Image acquisition from thick samples is time-consuming, but absolutely necessary for the research. Obtaining more sample image data in less time is always a tremendous advantage, allowing the researchers to be more productive.

The THUNDER Imager 3D Cell Culture visualizes an influenza (red) infected primary porcine lung epithelial grown in a multilayer of about 60 µm. The top layer shows cilia (green), which are responsible for mucus transport. Nuclei are stained in blue.
Raw image vs. Large Volume Computational Clearing. Courtesy of Dr. Stefan Finke, Friedrich-Loeffler-Institute, Riems (Germany).