A team of researchers from the Institute for Infectious Diseases (IFIK) at the University of Bern and the Federal Institute of Virology and Immunology (IVI) have assessed virus growth and activation of the cellular defense mechanisms in the respiratory tract. They have shown that natural temperature differences that exist in the upper and lower respiratory tract have a profound influence on SARS-CoV-2 replication and subsequent innate immune activation in human cells. The findings can help to develop antiviral drugs and preventive measures.
“SARS-CoV-2 and SARS-CoV are highly similar genetically, generate a homologous repertoire of viral proteins, and use the same receptor to infect human cells. However, despite these similarities, there are also important differences between the two viruses,” says Ronald Dijkman from the Institute for Infectious Diseases (IFIK) at the University of Bern. For example, SARS-CoV infection is characterized by severe disease and inflammation in the lower respiratory tract and infected individuals are only contagious after the onset of symptoms, making it easier to identify and interrupt infection chains.
In contrast, SARS-CoV-2 preferentially replicates in the upper airways (nasal cavity, pharynx, trachea) and can be efficiently transmitted from one individual to another before the appearance of disease symptoms. Moreover, the outcome of SARS-CoV-2 infection varies widely from person to person, and can manifest as asymptomatic, mild, or severe disease. Older people as well as individuals with certain underlying medical conditions (heart conditions, diabetes, cancer) are at greater risk of developing severe illness, which is often associated with infection of lower respiratory tissues, high levels of inflammation, and lung failure.
Temperature is key
To better understand why infections with SARS-CoV and SARS-CoV-2 result in such different clinical outcomes, researchers from the University of Bern used specialized human airway cell cultures to investigate the impact of respiratory tract temperatures on SARS-CoV and SARS-CoV-2 replication. The cells originate from human samples and mimic the complexity of the cells found in the respiratory tract. They grow in special containers, are nourished from the bottom side and are exposed to air on the top side, just like the cells in the human trachea. The cultures also make mucus and have cilia that beat very quickly. “Because the organization of these cells greatly resembles the cells found in human tissues, they are a relevant system that can be used in a laboratory to study respiratory viruses,” Dijkman explains.
The researchers have now used this existing model for the first time to study the effects of respiratory temperatures on SARS-CoV and SARS-CoV-2 replication. They found that temperature plays an important role as SARS-CoV-2 preferred to replicate at temperatures typically found in the upper airways (33°C). Colder incubation temperatures allowed the virus to replicate faster and to a higher extent than when infections were carried out at 37°C to mimic the lower lung environment. Unlike SARS-CoV-2, replication of SARS-CoV was not impacted by different incubation temperatures. The experiments were conducted both in the high security laboratory of the IVI in Mittelhäusern and in the biosafety laboratory of the Institute for Infectious Diseases (IFIK) at the University of Bern in the building of sitem-insel, the Swiss Institute for Translational Medicine and Entrepreneurship.
Image Credit: Uni. of Bern
Post by Amanda Scott, NA CEO. Follow her on twitter @tantriclens
Thanks to Heinz V. Hoenen. Follow him on twitter: @HeinzVHoenen
News
Scientists study lipids cell by cell, making new cancer research possible
Imagine being able to look inside a single cancer cell and see how it communicates with its neighbors. Scientists are celebrating a new technique that lets them study the fatty contents of cancer cells, [...]
Antibiotic Breakthrough: Revolutionary Chinese Study Paves Way for Superbug Defeating Drugs
New research reveals that fluorous lipopetides act as highly effective antibiotics. Bacterial infections resistant to multiple drugs, which no existing antibiotics can treat, represent a significant worldwide challenge. A research group from China has [...]
Signs of Multiple Sclerosis Show Up in Blood Years Before Symptoms Appear
UCSF scientists clear a potential path toward earlier treatment for a disease that affects nearly 1,000,000 people in the United States. By Levi Gadye In a discovery that could hasten treatment for patients with multiple [...]
Advanced RNA Sequencing Reveals the Drivers of New COVID Variants
A study reveals that a new sequencing technique, tARC-seq, can accurately track mutations in SARS-CoV-2, providing insights into the rapid evolution and variant development of the virus. The SARS-CoV-2 virus that causes COVID has the unsettling [...]
No More Endless Boosters? Scientists Develop One-for-All Virus Vaccine
End of the line for endless boosters? Researchers at UC Riverside have developed a new vaccine approach using RNA that is effective against any strain of a virus and can be used safely even by babies or the immunocompromised. Every [...]
How Are Hydrogels Shaping the Future of Biomedicine?
Hydrogels have gained widespread recognition and utilization in biomedical engineering, with their applications dating back to the 1960s when they were first used in contact lens production. Hydrogels are distinguished from other biomaterials in [...]
Nanovials method for immune cell screening uncovers receptors that target prostate cancer
A recent UCLA study demonstrates a new process for screening T cells, part of the body's natural defenses, for characteristics vital to the success of cell-based treatments. The method filters T cells based on [...]
New Research Reveals That Your Sense of Smell May Be Smarter Than You Think
A new study published in the Journal of Neuroscience indicates that the sense of smell is significantly influenced by cues from other senses, whereas the senses of sight and hearing are much less affected. A popular [...]
Deadly bacteria show thirst for human blood: the phenomenon of bacterial vampirism
Some of the world's deadliest bacteria seek out and feed on human blood, a newly-discovered phenomenon researchers are calling "bacterial vampirism." A team led by Washington State University researchers has found the bacteria are [...]
Organ Architects: The Remarkable Cells Shaping Our Development
Finding your way through the winding streets of certain cities can be a real challenge without a map. To orient ourselves, we rely on a variety of information, including digital maps on our phones, [...]
Novel hydrogel removes microplastics from water
Microplastics pose a great threat to human health. These tiny plastic debris can enter our bodies through the water we drink and increase the risk of illnesses. They are also an environmental hazard; found [...]
Researchers Discover New Origin of Deep Brain Waves
Understanding hippocampal activity could improve sleep and cognition therapies. Researchers from the University of California, Irvine’s biomedical engineering department have discovered a new origin for two essential brain waves—slow waves and sleep spindles—that are critical for [...]
The Lifelong Cost of Surviving COVID: Scientists Uncover Long-Term Effects
Many of the individuals released to long-term acute care facilities suffered from conditions that lasted for over a year. Researchers at UC San Francisco studied COVID-19 patients in the United States who survived some of the longest and [...]
Previously Unknown Rogue Immune Key to Chronic Viral Infections Discovered
Scientists discovered a previously unidentified rogue immune cell linked to poor antibody responses in chronic viral infections. Australian researchers have discovered a previously unknown rogue immune cell that can cause poor antibody responses in [...]
Nature’s Betrayal: Unmasking Lead Lurking in Herbal Medicine
A case of lead poisoning due to Ayurvedic medicine use demonstrates the importance of patient history in diagnosis and the need for public health collaboration to prevent similar risks. An article in CMAJ (Canadian Medical Association [...]
Frozen in Time: How a DNA Anomaly Misled Scientists for Centuries
An enormous meteor spelled doom for most dinosaurs 65 million years ago. But not all. In the aftermath of the extinction event, birds — technically dinosaurs themselves — flourished. Scientists have spent centuries trying [...]
