A team of Tel Aviv University researchers has demonstrated that antibodies isolated from the immune system of recovered COVID-19 patients are effective in neutralizing all known strains of the virus, including the Delta and the Omicron variants. The discovery may eliminate the need for repeated booster vaccinations and strengthen the immune system of populations at risk.

The research was led by Dr. Natalia Freund and doctoral students Michael Mor and Ruofan Lee of the Department of Clinical Microbiology and Immunology at the Sackler Faculty of Medicine and of the TAU Center for Combating Pandemics. The study was conducted in collaboration with Dr. Ben Croker of the University of California San Diego. Prof. Ye Xiang of Tsinghua University in Beijing. Prof. Meital Gal-Tanamy and Dr. Moshe Dessau of Bar-Ilan University also took part in the study. The study was published in the Nature journal Communications Biology.

Highly Effective Against Delta and Omicron

The present study is a continuation of a preliminary study conducted in October 2020, at the height of the COVID-19 crisis. At that time, Dr. Freund and her colleagues sequenced all the B immune system cells from the blood of people who had recovered from the original COVID strain in Israel, and isolated nine antibodies that the patients produced. The researchers now found that some of these antibodies are very effective in neutralizing the new coronavirus variants, Delta and Omicron.

“In the previous study, we showed that the various antibodies that are formed in response to infection with the original virus are directed against different sites of the virus,” says Dr. Freund. “The most effective antibodies were those that bound to the virus’s ‘spike’ protein, in the same place where the spike binds the cellular receptor ACE2. Of course, we were not the only ones to isolate these antibodies, and the global health system made extensive use of them until the arrival of the different variants of the coronavirus, which in fact rendered most of those antibodies useless.”

“In the current study, we proved that two other antibodies, TAU-1109 and TAU-2310, which bind the viral spike protein in a different area from the region where most of the antibodies were concentrated until now (and were therefore less effective in neutralizing the original strain) are actually very effective in neutralizing the Delta and Omicron variants. According to our findings, the effectiveness of the first antibody, TAU-1109, in neutralizing the Omicron strain is 92%, and in neutralizing the Delta strain, 90%. The second antibody, TAU-2310, neutralizes the Omicron variant with an efficacy of 84%, and the Delta variant with an efficacy of 97%.”

Can Serve as Effective Substitute for Boosters

According to Dr. Freund, the surprising effectiveness of these antibodies might be related to the evolution of the virus: “The infectivity of the virus increased with each variant because each time, it changed the amino acid sequence of the part of the spike protein that binds to the ACE2 receptor, thereby increasing its infectivity and at the same time evading the natural antibodies that were created following vaccinations.”

“In contrast, the antibodies TAU-1109 and TAU-2310 don’t bind to the ACE2 receptor binding site, but to another region of the spike protein – an area of ​​the viral spike that for some reason does not undergo many mutations – and they are therefore effective in neutralizing more viral variants. These findings emerged as we tested all the known COVID strains to date.”

“In our view, targeted treatment with antibodies and their delivery to the body in high concentrations can serve as an effective substitute for repeated boosters, especially for at-risk populations and those with weakened immune systems.” 

The two antibodies, cloned in Dr. Freund’s laboratory at Tel Aviv University, were sent for tests to check their effectiveness against live viruses in laboratory cultures at the University of California San Diego, and against pseudo viruses in the laboratories of the Faculty of Medicine of Bar-Ilan University in the Galilee; the results were identical and equally encouraging in both tests.

Dr. Freund believes that the antibodies can bring about a real revolution in the fight against COVID-19: “We need to look at the COVID-19 pandemic in the context of previous disease outbreaks that humankind has witnessed. People who were vaccinated against smallpox at birth and who today are 50 years old still have antibodies, so they are probably protected, at least partially, from the monkeypox virus that we have recently been hearing about. Unfortunately, this is not the case with the coronavirus. For reasons we still don’t yet fully understand, the level of antibodies against COVID-19 declines significantly after three months, which is why we see people getting infected again and again, even after being vaccinated three times.”

“In our view, targeted treatment with antibodies and their delivery to the body in high concentrations can serve as an effective substitute for repeated boosters, especially for at-risk populations and those with weakened immune systems. COVID-19 infection can cause serious illness, and we know that providing antibodies in the first days following infection can stop the spread of the virus. It is therefore possible that by using effective antibody treatment, we will not have to provide booster doses to the entire population every time there is a new variant.”

Featured image: Dr. Natalia Freund from the Sackler Faculty of Medicine (Photo: Yoram Reshef)

A new study from Tel Aviv University proposes a new learning method for people with autism that may accelerate the learning process and significantly improve capabilities in terms of visual perception. According to the researchers, improving the perceptual capacity of people with autism is often a challenge, and usually requires long and tedious training alongside additional learning challenges that characterizes autism, such as the ability to generalize learning to new situations.

The study was conducted by doctoral student Shira Klorfeld-Auslender and Prof. Nitzan Censor from the School of Psychological Sciences and the Sagol School of Neuroscience at Tel Aviv University, in collaboration with Prof. Ilan Dinstein and his team from Ben-Gurion University. The study was published in the journal Current Biology.

“A large part of learning does not happen in formal training settings but afterwards, through processes of assimilation and reinforcement of memory that occur in an ‘offline’ state; for example, when our brain is asleep.”

Longer Not Necessarily Better

The new method proposed by the researchers is based on utilizing “memory flashes,” by exposing a person for just a few seconds to a task that has already been learned. While standard teaching practice reinforce length and repetition of new skills, the new method improved both visual perception capabilities and the generalization of learning through helping the subjects excel in the same tasks, under different conditions.

“In my laboratory, we focus on the study of learning in humans, and we know that a large part of learning does not happen in formal training settings but afterwards, through processes of assimilation and reinforcement of memory that occur in an ‘offline’ state; for example, when our brain is asleep,” explains Prof. Censor.

“However, standard teaching methods still advocate an approach where longer practice equals better learning: if you want to play the piano, you should practice playing the piano for many hours every day until the playing becomes second nature to you. We have identified an alternative learning mechanism that uses ‘memory flashes’ – a brief exposure to a task that has already been learned –to assimilate and generalize skill developed.”

Prof. Nitzan Censor

Effective with Added Value

In the study, 30 high-functioning adults with autism were asked to learn a visual task (for example, identifying the direction of lines that appear for a few milliseconds on the screen). However, instead of repeating the task for a long time each day, the examinees in the main experimental group learned the task in depth on the first day, and in the following days they were exposed to the visual stimulus for only a few seconds. At the end of the process, although the study participants studied the task for a minimal amount of time, their performance improved significantly, by about 20–25%, which was a similar result to those subjected to multiple-repetition learning and to the achievements of subjects without autism.

“We have shown that it does not take prolonged practice time to assimilate the task – it is enough to flash it for a few seconds to stimulate the relevant brain network, and the brain will then assimilate the material on its own.”

Moreover, even when presented with the task under new conditions (for example, when the stimulus was learned in a new location), the examinees who learned with the memory flash method performed better than those in the control group – they knew how to generalize the skills learned in the first task. The participants’ success in generalizing the learning to other situations is considered significant, as these are skills that people with autism tend to struggle with.

“We have already proven in previous studies that processes of learning assimilation can be improved through flashes of memory,” says Prof. Censor. “We have shown that it does not take prolonged practice time to assimilate the task – it is enough to flash it for a few seconds to stimulate the relevant brain network, and the brain will then assimilate the material on its own.”

“In this case, we tested people with autism. People with autism often have difficulty learning and generalizing repetitive learning, that is, using tools that have also been learned when executing new tasks. Through short flashes of visual stimulus of a task learned, we were able to produce learning that is identical to repetitive learning in terms of its effectiveness; meaning, we significantly shortened the learning time. The added value is the ability to generalize: the examinees performed a task under new conditions, as if they had fully learned it. “

According to Prof. Censor, the new method may have significant potential implications in a wide range of areas. The new study could pave the way for more meaningful approaches to learning for people with autism, and in a wide variety of tasks. Moreover, the method may contribute to shorten rehabilitation after neurological injuries.