(Press-News.org) Months after recovering from mild cases of COVID-19, people still have immune cells in their body pumping out antibodies against the virus that causes COVID-19, according to a study from researchers at Washington University School of Medicine in St. Louis. Such cells could persist for a lifetime, churning out antibodies all the while.
The findings, published May 24 in the journal Nature, suggest that mild cases of COVID-19 leave those infected with lasting antibody protection and that repeated bouts of illness are likely to be uncommon.
"Last fall, there were reports that antibodies wane quickly after infection with the virus that causes COVID-19, and mainstream media interpreted that to mean that immunity was not long-lived," said senior author Ali Ellebedy, PhD, an associate professor of pathology & immunology, of medicine and of molecular microbiology. "But that's a misinterpretation of the data. It's normal for antibody levels to go down after acute infection, but they don't go down to zero; they plateau. Here, we found antibody-producing cells in people 11 months after first symptoms. These cells will live and produce antibodies for the rest of people's lives. That's strong evidence for long-lasting immunity."
During a viral infection, antibody-producing immune cells rapidly multiply and circulate in the blood, driving antibody levels sky-high. Once the infection is resolved, most such cells die off, and blood antibody levels drop. A small population of antibody-producing cells, called long-lived plasma cells, migrate to the bone marrow and settle in, where they continually secrete low levels of antibodies into the bloodstream to help guard against another encounter with the virus.
The key to figuring out whether COVID-19 leads to long-lasting antibody protection, Ellebedy realized, lies in the bone marrow. To find out whether those who have recovered from mild cases of COVID-19 harbor long-lived plasma cells that produce antibodies specifically targeted to SARS-CoV-2, the virus that causes COVID-19, Ellebedy teamed up with co-author Iskra Pusic, MD, an associate professor of medicine. Ellebedy already was working with co-authors Rachel Presti, MD, PhD, an associate professor of medicine, and Jane O'Halloran, MD, PhD, an assistant professor of medicine, on a project to track antibody levels in blood samples from COVID-19 survivors.
The team already had enrolled 77 participants who were giving blood samples at three-month intervals starting about a month after initial infection. Most participants had had mild cases of COVID-19; only six had been hospitalized.
With Pusic's help, Ellebedy and colleagues obtained bone marrow from 18 of the participants seven or eight months after their initial infections. Five of them came back four months later and provided a second bone marrow sample. For comparison, the scientists also obtained bone marrow from 11 people who had never had COVID-19.
As expected, antibody levels in the blood of the COVID-19 participants dropped quickly in the first few months after infection and then mostly leveled off, with some antibodies detectable even 11 months after infection. Further, 15 of the 19 bone marrow samples from people who had had COVID-19 contained antibody-producing cells specifically targeting the virus that causes COVID-19. Such cells could still be found four months later in the five people who came back to provide a second bone-marrow sample. None of the 11 people who had never had COVID-19 had such antibody-producing cells in their bone marrow.
"People with mild cases of COVID-19 clear the virus from their bodies two to three weeks after infection, so there would be no virus driving an active immune response seven or 11 months after infection," Ellebedy said. "These cells are not dividing. They are quiescent, just sitting in the bone marrow and secreting antibodies. They have been doing that ever since the infection resolved, and they will continue doing that indefinitely."
People who were infected and never had symptoms also may be left with long-lasting immunity, the researchers speculated. But it's yet to be investigated whether those who endured more severe infection would be protected against a future bout of disease, they said.
"It could go either way," said first author Jackson Turner, PhD, an instructor in pathology & immunology. "Inflammation plays a major role in severe COVID-19, and too much inflammation can lead to defective immune responses. But on the other hand, the reason why people get really sick is often because they have a lot of virus in their bodies, and having a lot of virus around can lead to a good immune response. So it's not clear. We need to replicate the study in people with moderate to severe infections to understand whether they are likely to be protected from reinfection."
Ellebedy and colleagues now are studying whether vaccination also induces long-lived antibody-producing cells.
INFORMATION:
A critical process in the infection cycle of viruses has been revealed for the first time in dynamic detail using pioneering plant-based technology.
Evidence about the process of virus maturation revealed in the research could help us develop new methods for treating viral infections.
Maturation plays a critical role for all animal and bacterial viruses and is required to produce infectious virions or particles. Though the outlines of the process have been determined for many groups of viruses, detailed mechanistic studies have not been reported.
To provide the first detailed mechanistic study of maturation, Roger Castells-Graells, ...
The research team led by Prof. DU Pingwu from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS) first successfully synthesized an all-phenylene bismacrocycle (bis- means two) with Siamese-twin structure and used fullerene as guest molecules to assemble a peanut-shaped supramolecular complex. This study was published in Angewandte Chemie.
As a new type of carbon material, carbon nanotubes (CNTs) have attracted widespread attention because of their outstanding mechanical and photophysical properties. However, the synthesis of CNTs or CNTs fragments with selective simple structure is still a challenge.
This study reported a conjugated highly strained all-phenylene Siamese-twin bismacrocycle, SCPP[10]. Two phenylene nanorings, [10]CPP, conjoined ...
Research co-led by Newcastle University has shed new light on important microscopic scale interactions between algae and bacteria predicated on the mutually beneficial exchange of nutrients.
The research was carried out at the University of Cambridge and the Nordsim laboratory at the Swedish Museum of Natural History in Stockholm by Dr Hannah Laeverenz Schlogelhofer, now at the University of Exeter, and a team led by Dr Ottavio Croze, of Newcastle University's School of Mathematics, Statistics and Physics.
They have used an advanced high-spatial resolution isotope mapping technique called 'SIMS' (secondary ion mass spectrometry) to chart for the first time how long it takes for labelled carbon produced by microalgae to be transferred ...
A supersensitised brain connection has been identified in people who suffer from misophonia, an extreme reaction to "trigger" sounds.
For the first time, researchers led by Newcastle University, have discovered increased connectivity in the brain between the auditory cortex and the motor control areas related to the face, mouth and throat.
Publishing today, in the Journal of Neuroscience, lead author Dr Sukhbinder Kumar, Newcastle University Research Fellow in the Biosciences Institute said: "Our findings indicate that for people with misophonia there is abnormal communication between the auditory and motor ...
Posts to Reddit forum "SuicideWatch" spike in the early hours of Monday morning
New research from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King's College London has found that people on a social media suicide support forum are most likely to post to the site during the early hours of Monday morning.
The study, which has been published in BMC Psychiatry, suggests that there is a clear variation in behaviour throughout the week and throughout the day. The researchers hope that this means that targeted support to at risk populations can be made more readily available to those most in need.
The researchers looked at the timings at which users of the Reddit ...
The study, published in the journal Nature Aging and led by the laboratories of Dr. Alberto Pascual (CSIC), from the Neuronal Maintenance Mechanisms Group, and Prof. Javier Vitorica (University of Seville/CIBERNED) of the Physiopathology of Alzheimer's Disease Group at IBiS, demonstrates for the first time that low oxygen levels in the so-called senile plaques in the brain reduces the immune system's defensive capacity against the disease.
The study also suggests that this lack of oxygen in the brain enhances the action of disorders associated with Alzheimer's disease that are characterised by low systemic oxygen levels, such as atherosclerosis and other cardiovascular diseases.
What happens ...
Forensic archaeologists and anthropologists from Cranfield University have started to recover the bodies of victims executed by the Franco regime at the end of the Spanish Civil War during an excavation in the Ciudad Real region of Spain.
The team from Cranfield is working with partners from the University Complutense of Madrid (UCM) and social anthropologists from Mapas de Memoria (Maps of Memory) to search for, exhume and identify those executed and buried in the civil cemetery at Almagro between 1939 and 1940.
Several bodies with gunshot wounds to the head, personal effects and parts of clothing ...
For many diseases, overweight and obesity are risk factors. But now a study shows that a higher BMI may be linked to higher survival rates in patients hospitalized for severe bacterial infections.
Scientists at Sahlgrenska Academy, University of Gothenburg, and Skaraborg Hospital in Skövde carried out the research, and their study has now been published in the journal PLOS ONE. The data were collected before the COVID-19 pandemic.
The population-based study involved observations, over a nine-month period, of all 2,196 individual adults receiving care for suspected severe bacterial ...
In his most recent published research, appearing in Applied Thermal Engineering, City, University of London's Dr Martin White explores a novel organic Rankine cycle system, based on a two-phase expansion through numerical simulations of the system.
His paper, Cycle and turbine optimisation for an ORC operating with two-phase expansion, considers the use of modern fluids whose properties could help to mitigate concerns around turbine damage, whilst allowing the benefits of two-phase expansion to be realised.
Waste heat from a range of industries, ranging from iron and steel to food and drink, ...
It has been documented over hundreds of years that various electromagnetic anomalies occur during a few weeks before the occurrence of a large earthquake. These electromagnetic anomalies are variations that appear in telluric current, geomagnetism, electromagnetic waves etc. before the earthquake.
Although there are various models to explain the mechanism, the large current generated at the source was not fully explained. For example, many researchers thought that the stress applied to the fault produced an electric current, but the stress applied to the fault takes place over hundreds or thousands of years before the occurrence of the earthquake. It is a common belief among seismologists ...