Do you know which hormones bring happiness to humans?

Are you happy?

In fact, happiness is partly a chemical experience, the brain releases happy substances, we feel happy.

So, do you know which hormones make people happy?

Here are four happy hormones to share with you. With this knowledge, when we are unhappy or depressed, we can use different methods to find happiness.


The reward hormone dopamine

Dopamine affects our feelings, mood and even our ability to learn, and can be stimulated by eating food containing tyrosine and antioxidants, or by listening to music or getting enough sleep.


Mood stabilizer — serotonin

Serotonin is a neurotransmitter that carries messages between nerve cells in the brain and is a natural mood stabilizer. Eat foods rich in tryptophan and vitamin B; Or activities such as meditation or sun exposure can increase serotonin production.


The intimacy hormone oxytocin

Oxytocin helps us trust others, form close and healthy relationships with others, and trigger feelings of belonging and attachment to a group. Oxytocin is not naturally available in food, but is often obtained through other means, such as human interaction, petting animals, and massage.


Natural painkillers – endorphins

Endorphins are neurotransmitters that help the body process pain, stress and emotions, and are responsible for making people feel good. Endorphins can be experienced by eating dark chocolate, chili peppers, ginseng, and vanilla, as well as by creating and exercising.

Novel coronavirus infections in more than 12.5 million children in the United States

More than 12.5 million children in the Us have been confirmed with novel coronavirus infections since the start of the COVID-19 outbreak, according to a new report released by the American Academy of Pediatrics and the Association of Children’s Hospitals on Tuesday. “The accelerated spread of the novel Coronavirus strain of omicron in the United States this year has led to a surge in the number of confirmed cases of COVID-19 in CHILDREN in the United States,” the report said. Since the beginning of January, there have been more than 4.6 million new confirmed cases of COVID-19 in children in the United States. More than 470,000 new cases have been reported in children nationwide in the past two weeks.

Novel Coronavirus may coexist with humans

With the prolonged outbreak of COVID-19, there is increasing public interest in the Novel Coronavirus situation and containment measures. On February 19, the 94th Pearl River Science Lecture hall was held at guangdong Science Center. Guo Jun, director and doctoral supervisor of State Key Laboratory of Applied Microbiology in South China, was invited to deliver a popular science lecture on the origin of Microbiology and THE prevention and control of COVID-19. In his speech, Guo Jun introduced the development of microbiology from modern times to the present, and from this led to the discussion of novel Coronavirus and the analysis of the trend of COVID-19 epidemic.

Less than 1% of microbes are harmful to humans

What are microbes? Microbe is a general term for all tiny organisms that are difficult to see with the naked eye and require light or electron microscopes, including bacteria (such as lactic acid bacteria, tuberculosis bacillus), viruses (such as rabies virus), fungi (such as Aspergillus aflatus), protozoa (such as green eye worms) and a few algae, Guo said. In addition, some microbes are large enough to be seen with the naked eye, such as large fungi such as mushrooms. Guo noted that microbes are abundant in number and variety, but most of them are harmless to humans. Less than 1% of them are harmful to humans, but almost all infectious diseases are caused by microbes.

Although small in size, microorganisms play a very important role in the circulation of matter in nature. Plants are the synthesizers of matter and the transmutators of matter in the animal world, while microorganisms act as decomposers and cleaners of nature. Some microorganisms also participate in photosynthesis and nitrogen fixation. Without microbes, it could be said, no other life on Earth could survive.

The existence of microbes was not discovered until modern times, guo said. In the mid-17th century, a Dutchman named Leeuwenhoek polished his lens, scraped material from his teeth and put it under the lens. He found microscopic creatures moving. That was how microbes were first observed.

Time came to the 19th century, people explored the relationship between fermentation and microorganism, and found that yeast is a living organism that can cause fermentation. Since then, French scientists Pasteur and German scientists Koch began to study how to use microorganisms to promote production and improve life. Pasteur discovered that the multiplication of microorganisms caused wine to turn sour, and invented Pasteur disinfection method, made an important contribution to the wine industry. Koch invented Koch’s Law, which put forward that many diseases are caused by microorganisms, laying a foundation for the development of later medical career.

In 1928, British Fleming found a sterile circle around penicillium in a petri dish growing staphylococcus bacteria. Rather than ignore his unexpected discovery, he continued his research and eventually invented the first antibiotic, penicillin, or penicillin. For nearly a century, the drug saved countless lives.

In the course of introducing the history of microbiology, Guo jun said that the most important thing for scientific research is interest. Scientific research workers in the interest of the drive, to maintain focus, continue to explore the unknown, to contribute to the development of modern science.

The vaccine helped reduce the number of severe cases

According to Guo jun, novel Coronavirus is a new type of virus, and viruses are an important part of microbial populations. Therefore, the study of novel Coronavirus and pneumonia epidemic is also an important topic of microbiology research.

He said the total number of novel coronavirus infections in the world now exceeds 400 million, including 77 million in the United States. The number of infections increased by 100 million in a single month from January 7 to February 8 this year, thanks to the introduction of a new variant of omicron in November 2021. The five countries with the most cases are the United States, India, Brazil, France and the United Kingdom.

Guo then analyzed why people get infected with COVID-19 even after getting vaccinated. Novel Coronavirus viruses are RNA viruses of respiratory tract infection. They spread rapidly and are prone to mutation. From the human perspective, it takes time for antibody production to peak, and the duration of antibody potency maintenance also needs to be studied.

As for the effectiveness of the vaccine, Guo explained that after three doses of vaccine, the human body produces Igg and IgM antibodies, which play a protective role. Vaccines contribute to the reduction of severe cases, leading to a significant reduction in mortality, which facilitates “dynamic zeroing” and “herd immunity”.

Finally, Guo analyzed the future trends of COVID-19 infection. Guo jun believes that in the future, there is a possibility of a weakened epidemic of novel Coronavirus, which may coexist with humans. However, Omicron is not a large flu, so we cannot downplay the seriousness of the epidemic and weaken the level of attention. Right now, the fatality rate is 2%, lower than SARS and MERS, but the Novel Coronavirus has the greatest impact on humans.

It is thought that the more transmissible the virus is, the less virulent it is and the less virulent it is. But Guo argues that this view is basically impossible to be biologically correct. In addition, COVID-19 can weaken the body’s immunity and cause a variety of sequelae, including mental retardation, bone disease, and internal and vascular problems. Therefore, Guo jun believes that in order to ensure people’s life and health safety, in the absence of a better way to control the epidemic, the “dynamic zero” strategy will not be adjusted for the time being.

Us army virus outbreak has become a foregone conclusion, a large number of soldiers into panic

According to the American “the star-spangled banner” for the latest news, the pentagon said, by the 24th, 174 soldiers and 150 American families and the contractor has already confirmed will be coronavirus, and confirmed the scope of all over the world around us, it shows that in the internal virus outbreak has become a foregone conclusion, but to the large number of soldiers in a panic, although the number of confirmed linear increase, But the serious shortage of epidemic prevention materials, many American soldiers perform dangerous contact task doesn’t even have a mask, only face to face with the virus may threaten, the pentagon said the have enough protective supplies, tough ordered a large number of us troops deployed across the country, military experts say, strong ability of new the spread of the virus, Many U.S. troops deployed in hard-hit states such as New York, California and Washington do not have proper protection, raising the possibility that U.S. troops could become infected. Given the surge in confirmed cases, it may be too late to wear masks now.

U.S. defense secretary mark – ace pearl and the chairman admiral mark – he said, from the experience of other countries, it will take about 3 months the outbreak will be effectively controlled, if the guess is correct, then the epidemics in the United States in May and June or July to get most effectively, and the U.S. will take all means to help put out the spread of the virus, Us Army Secretary Ryan McCarthy has ordered the us army to relocate three field hospitals to the hardest-hit states of New York, California and Washington. A spokesman for the US Army said the deployment could be completed in as little as seven days. Each hospital can provide up to 250 beds.

But thought, considering as of March 25, at 6 o ‘clock, confirmed the number has reached 53268 people in the United States, its new number broken, in fact the several field hospital or hospital ship into it simply can’t afford to turn what waves, what’s more, American is own yourself, armed forces have begun a wide range of screening, Even the NUCLEAR-powered aircraft carrier USS Roosevelt, which had been deployed at sea before, reported three confirmed cases, indicating that the US military has been seriously affected by the epidemic. Even so, senior US military officials still said that the impact of the epidemic on the US military is “very limited” so far, and the US military is able to complete the set military mission.

But at the top of blind confidence cannot make us at ease at the grass-roots level, many American troops have complained that they were ordered to travel to the disaster zone, “to help stabilize the situation, but it doesn’t even have basic protective supplies, from the perspective of a public photos, many outbreaks, such as deployment of U.S. troops in New York even not wearing masks, said the army, there are already suspected cases, Considering within the organization form of army is very close, each other of a soldier is also very intense and frequent contact, once appear, therefore not controlled transmission phenomenon, so the effectiveness will be severely affected, although the top announced to enlarge the production of medical supplies, even to South Korea and other countries for help, but it is also far hydrolyze not close thirsty. The lack of medical supplies for American troops will not ease in the short term.

In South Korea, the number of novel coronavirus infections exceeded 1.75 million in just seven days

Seoul, South Korea — South Korea will extend restaurant meal hours but keep a six-person limit on private social gatherings as it deals with a massive coronavirus wave driven by the highly contagious Omicron mutation.

The 109,831 new cases reported Friday are another record and represent a roughly 25-fold increase from mid-January, when omicron became the country’s dominant strain. More than 516,000 infections in the past seven days alone bring the number of cases in South Korea to more than 1.75 million.

In the densely populated capital, Seoul, long lines formed around public health offices and testing stations, where health workers in hazsuits distributed rapid antigen test kits and collected throat and nasal samples from the elderly and other high-risk groups.

There are also concerns that campaigning for the March 9 presidential election could intensify transmission. Thousands of supporters were summoned by the ruling party candidate Lee Jae-Myung in the southwestern city of Suncheon, where they clapped, shouted and chanted his name. Lee’s conservative rival Yin Shuyang also drew a large crowd at a rally in the southeastern city of Sangzhou.

So far, Omicron seems less likely to cause serious illness or death than the Delta variant that hit the country hard in December and January. But cases are rising faster and appear to be putting the country on the verge of a hospital explosion.

Prime Minister Kim Bok-kim, the no. 2 official in Seoul behind President Moon Jae-in, acknowledged people’s frustration with the extended virus restrictions and the impact on businesses in the service sector, but said officials were unable to significantly ease social distancing when hospitalizations and deaths began to climb.

Officials did extend a curfew for restaurants and other businesses from 9 p.m. to 10 p.m., but private social gatherings of seven or more people will remain banned until at least March 13.

People will continue to be required to show their vaccination status via a smartphone app or file to enter potentially crowded Spaces such as restaurants, coffee shops, gyms and karaoke establishments.

“Experts expect [the Omicron outbreak] to peak sometime in late February to March,” Kim said at a conference on antivirus strategy. “When we can confirm the point at which [the epidemic] has peaked and is declining, we will, like other countries, begin to meaningfully relax social distancing measures so people can resume their precious normal lives.”

About 30% of intensive care units designated for Novel Coronavirus treatment are currently occupied, the Ministry said. The health ministry said 385 patients with the virus were in serious or critical condition, up from 100 more than a week ago but still down from about 1,000 during the delta outbreak in late December.

Although Omicron is more likely to infect those who have been previously vaccinated or infected with novel coronavirus, experts say vaccination and booster shots still offer strong protection against severe illness and death.

More than 86 percent of South Koreans have been fully vaccinated and 58 percent have received booster shots. Health officials began offering the fourth vaccination in nursing homes and other long-term care Settings.

A world first! Women who have recovered from AIDS or have appeared, the blood has no HIV virus

Speaking of AIDS, it is a retreat, this is a disease that can not be cured, can only take medicine to control, once the infection, want to heal, it is almost impossible, at least with the current level of medicine, AIDS this disease, or helpless, so far, there is no cure for AIDS specific drug.

In this context, there was the world’s first female AIDS “cure”, it was a boiling, you know, by 2020, a total of 37.7 million people living with HIV worldwide, died of AIDS every year there are hundreds of thousands of patients, in such cases, the world’s first female “cured” of HIV/AIDS, can not surprising?

What does that mean?

This news, is published by American researchers, since it is “cured”, does it mean that the United States has broken through the treatment of AIDS?

In fact, although this is the first case of women “cured”, but in fact this is the third case of AIDS patients have been “cured”, although this number compared to the total number, it is pitiful, but it is undoubtedly to bring hope to AIDS patients.

We need to know that AIDS is a very dangerous infectious disease, HIV will attack the immune system of the human body, resulting in the loss of immune function of the human body, so that it will be infected with various diseases, there will be a lot of disgusting tumors, and the fatality rate is very high.

Terrible is that THE AIDS virus has an incubation period of 8-9 years, and in the latent period, can live and work without any symptoms, and normal people, mainly through X contact, blood and mother-to-child transmission, so under normal circumstances, is not contagious, which we do not have to worry about.

This middle-aged woman is not only the world’s first female “cure”, but also the first successful AIDS case through the transplantation of umbilical cord stem cells.

According to the report, the woman was diagnosed with HIV in 2013 and acute myeloid leukemia four years later.

The weill Cornell Medical College team had just developed a haploid cord blood transplant, so the woman took the treatment not only for her own sake, but also for the sake of AIDS research.

She received a special umbilical cord blood from a donor, which contained the mutations necessary to fight HIV, and received an adult stem cell transplant.

Only two men had been cured in this way before, but the ripple effect was unpredictable.

For example, these two men, although their bodies are free of HIV, due to the collapse of their own immune system, resulting in serious sequelae, including the donor cells, are still attacking the body, the two men are also in very bad condition.

But the end result unexpectedly, this woman after transplantation, no cells against itself, which is graft versus host disease, and transplant 3 years later, to stop the treatment for HIV/AIDS, 14 months passed, and still no relapse, and the testing of many times, has not the existence of the HIV virus in the blood.

So the woman became the first “cured” of HIV/AIDS cases by transplantation of umbilical cord stem cells, could be a real “recovery”, although is healed, the future is unknown, but for the moment, it is absolutely a good result, for HIV/AIDS patients, is undoubtedly a save “rice line”.

So, this kind of umbilical cord blood transplantation, can be promoted?

In fact, however, because of the need is specific to the fight against HIV/AIDS virus of cord blood, so that the number of umbilical cord blood is very little, coupled with the result of the treatment is not guarantee success, popularizing the scope is too small, can only say to HIV/AIDS patients, offers a new curative therapy, also has brought more promising, in short too much better than before.

Because the treatment cannot be widely promoted and the woman’s condition is still under observation, the American research team only called it a “remission” of AIDS, and waited to see if the word “cure” could be used.

So how long do people with AIDS live?

Earlier, China’s CENTER for Disease Control and Prevention reported that in 2020, The number of AIDS patients in China reached 1,053,000, and the death toll was as high as 351,000. This death rate is very terrible. What is terrible is that the infection rate of our students is increasing at a rate of 35% every year.

It can be seen that THE mortality rate of AIDS is very high, so many people are curious about how long they can live after suffering from AIDS, which also has individual differences. However, according to the clinical data, the longest survival time of AIDS patients recorded has been 27 years, so this time is not too short.

Of course, if their high-risk behavior, doubt themselves likely infected with AIDS, so after the high-risk behavior, 72 hours, immediately seek medical help, to carry on the block, this time, there is a great chance to block a success, the biggest problem, is promiscuous, X partner more, must be extremely seriously.

Nevertheless, it is a great thing that such a treatment has been developed, and it is a great breakthrough in the field of medicine.

The new report says the effectiveness of the third dose wanes after four months, with natural immune antibodies lasting longer

After about four months, a third dose of the coronavirus vaccine is much less likely to prevent serious illness, according to a new study released Friday by the CENTERS for Disease Control and Prevention.

The study looked at cases in 10 states from August 26, 2021, to January 22, 2022. CDC data showed that during the Omicron era, the effectiveness of the third booster for hospitalizations dropped from 91 percent in the first two months after the injection to 78 percent in about the fourth month. At the same time, the effectiveness of the emergency department went from 87 percent at two months to 66 percent at four months, and only 37 percent after about five months.

The new data support previous studies that showed that the Pfizer and Modena vaccines, with either two or three doses, were less effective when Omicron and Delta were dominant.

The new study has limitations, though — the data did not differentiate between why people who received the third booster shot were vaccinated, did not break down effectiveness by age group, or say whether the people being followed had underlying health conditions. The cases followed did not take into account no medically reported viral infections and did not identify which variants were present in the cases.

The debate over whether vaccines should be used has raged throughout the COVID-19 pandemic, and while the CDC reports that vaccines are starting to wane again, a new Israeli study reignites the debate over whether natural immunity or vaccine-induced protection is better.

Israel was one of the first countries in the world to launch a vaccine. A recent report from the Sheba Medical Center in Ramat Gan, The country, shows that COVID-19 survivors who have never been vaccinated have more lasting immunity than those who have been vaccinated twice but have never been infected.

The study followed more than 500 people who had been infected or vaccinated twice between 2020 and 2021. Of those, 130 were people who became infected without vaccination between March 2020 and November 2021. 402 people who received the second injection at the end of 2020 but never became infected.

Participants were observed for up to a year, with experts measuring antibody levels in patients’ blood immediately after they were infected or vaccinated, and follow-up tests six months later. The researchers also measured antibody affinity – how well the infection-fighting protein binds to the target virus.

While the vaccinated people initially had higher levels of antibodies, they dropped by much more than the naturally immunized group. The vaccinated people initially saw higher levels of antibodies and higher affinity. But after six months, both measures were lower than those in the naturally immunized group, while antibody levels dropped more and more slowly in those who recovered. After six months, affinity actually seemed to increase. Although researchers can’t explain why.

The graph shows two distinct downward trends in antibody affinity — the degree to which the infection-fighting protein binds to the target virus — among COVID-19 survivors (red) or vaccinators (blue).

“While antibody quantity decreases over time in all cases, the quality of antibody increases after infection in unvaccinated COVID-19 survivors but not in vaccinated COVID-19 survivors,” the researchers wrote in the study.

But the Israeli-led study only looked at antibodies. Immunity also involves T cells and other white blood cells that are harder to measure but can provide longer-lasting protection. At the same time, the study does not necessarily reflect immunity to later variants such as Omicron.

The findings will be presented at the European Congress of Clinical Microbiology and Infectious Diseases in Lisbon, Portugal, in April.

In addition, in January, the CDC reported that people who had previously been infected with COVID-19 were more resistant to the Delta variant than those who had only been vaccinated, according to data from health departments in California and New York, suggesting that natural immunity was more effective than the vaccine against the variant.

Health officials in California and New York collected data from May to November 2021, including a period when the Delta variant was dominant. The study showed that protection against Delta was highest among vaccinated convalesces, followed by unvaccinated convalesces, and lowest among never-infected or vaccinated convalesces.

People who were vaccinated but not infected in California and New York had a 6.2-fold and 4.5-fold reduction in COVID-19 rates, respectively, compared with the base population that was neither infected nor vaccinated. But among unvaccinated survivors, the rate was 29 times lower in California and 14.7 times lower in New York. Those who were best protected from infection were vaccinated survivors, whose infection rates were 32.5 times lower in California and 19.8 times lower in New York.

A Danish study published in December also confirmed that natural immunity protects against infection better than vaccines. It shows that vaccine-induced immunity begins to weaken rapidly a few weeks after vaccination. At the five-month mark, the protection rate was well below 50%. Natural immunity, by contrast, is strong: protection remains above 70 per cent for a full year after infection.

“After two years of accumulating data, it is clear that natural immunity is superior to vaccination,” said Dr. Marty Makary of Johns Hopkins University. Makary notes that the United States is one of the few countries that ignores natural immunity.

But many experts say the “jury is still out” on whether natural immunity provides better protection against the virus.

Professor Danny Altman, an immunologist at Imperial College London, said: “This study touches on some of the difficult questions we are all grappling with in human immunology at this stage of the pandemic, and there is more work to be done. There is consensus on the quality, quantity, and durability of protective immunity through infection, vaccination, and the jury is still out.”

Dr Julian Tang, a clinical virologist at the University of Leicester, said: “In general, natural infections produce a broader and longer-lasting immune response to all viral antigens – so this is not surprising. After all, our immune system has evolved over millions of years to deal with all types of pathogens — so I expect natural immunity to trump any vaccine-induced immunity in the long run.”

But one consensus is that all scientists agree that a combination of vaccines and natural immunity is best. The risk of severe illness, hospitalisation, long-term sequelae and death from initial infection among unvaccinated persons remains substantial. The CDC also advises all eligible people to “stay up-to-date on recommended COVID-19 vaccinations to best protect against covid-cov-related hospitalizations and emergency care.”

Norovirus from eating raw oysters?

Winter is the peak season for norovirus. Recently, there have been many cases of norovirus infection caused by eating raw oysters in South Korea, and norovirus has been detected in shellfish farms in many places, which has aroused great concern in South Korea.

In South Korea, people like to eat oysters raw to taste their original taste, especially in winter when they are at their richest.

However, the Korea Disease Control and Prevention Agency (KCDC) said that people in many parts of South Korea have recently experienced vomiting and diarrhea caused by eating raw oysters. The main cause is the detection of norovirus in shellfish such as oysters. According to the latest figures, the number of norovirus cases in South Korea has exceeded 200 this month, with young people in their 20s and 30s accounting for nearly half.

To this, south Korean Marine fisheries agency respectively in the near future also to the national home oyster farms were tested, the result found with past only waters in the south of Han Guotong camp, koje farms appear, such as viruses, also for the first time this year in the west of zhong qing south road and incheon area to detect the virus, and showed a trend of spreading across the country.

South Korean Marine fisheries agency speculate that this may be related to rainfall last year led to the more the more than on land, such as virus with rainwater flows into the sea, for production and processing enterprises in ensuring oyster safety delay before shipment, at the same time, strict regulation related businesses in the oyster products logo on the label “heating cooking food” again after sales, to remind consumers not to eat raw.

South Korean oysters are not only popular among local people, but also exported overseas. Reporters also immediately contacted the relevant departments, the person in charge said it was not clear whether the oysters infected with norovirus had been exported to the Chinese market.

Scientists discover more deadly HIV virus

A new variant of the human immunodeficiency virus (HIV) has been discovered in the Netherlands that, compared to other versions of the virus, appears to cause Disease progresses faster.

HIV infects and destroys immune cells in the body called CD4 cells, causing a reduction in the number of these cells, the report said. If left untreated, the infection can progress to AIDS. In people infected with this newly discovered HIV variant — the “VB variant” — CD4 cell counts declined about twice as fast as those with other B subtypes.

Without treatment, on average, a VB variant infection may progress to AIDS within two to three years of initial HIV diagnosis, researchers report Feb. 3 in the journal Science. Other versions of the virus, on average, did not experience a similar degree of exacerbation until about six to seven years after diagnosis.

“We found that, on average, people infected with this variant, if they did not start treatment, And if HIV infection is diagnosed in the 30s, the infection is expected to progress from diagnosis to ‘advanced HIV’ within nine months.” The disease progresses faster in older adults, he said.

Fortunately, the team found that antiretroviral drugs worked just as well on the VB variant as they did on other versions of the virus. “In individuals who are successfully treated, deterioration of the immune system is suppressed and transmission of the virus to others is avoided,” Wymant said.

“The study authors used this case study to underscore the importance of universal access to treatment,” said Katie Atkins, a researcher at the University of Edinburgh School of Medicine and associate professor at the London School of Hygiene and Tropical Medicine, who was not involved in the study. “Not only because we want to directly reduce the number of people dying from AIDS unnecessarily, but also because it reduces the likelihood of new, more deadly variants emerging,” he told this website in an email.

Wymant and the study’s senior author, infectious disease epidemiologist Christopher Fraser, are key members of the BEEHIVE research program, which aims to better understand the biology, development and epidemiology of HIV . “The BEEHIVE project started in 2014 to understand how changes in this virus lead to differences in disease,” said Wymant. “The project brought together data from seven countries in Europe, as well as Uganda.”

In analyzing data from the ongoing study, the team found 17 people infected with “significantly different” HIV variants, all of whom were in the early stages of infection — between six months and two years after diagnosis, the report said. In between – the blood is carrying very high concentrations of the virus. Fifteen of them were from the Netherlands, one from Switzerland and one from Belgium.

The research team found that this newly discovered variant belongs to the B subtype. To see if they could find more examples of this variant in the Netherlands, the researchers screened data from the Netherlands AIDS Treatment Assessment (ATHENA).

Of these, more than 8,000 of whom had viral genetic sequence data available, about 6,700 of whom were reported to be infected with subtype B. In this group of people, the researchers found 92 people infected with the VB variant, bringing the total number of people infected with this variant to 109.

Based on available clinical data, these 109 people had a viral load that was 3.5 to 5.5 times higher than those infected with other B subtypes. At diagnosis, people infected with the VB variant already had lower CD4 cell counts than those infected with the other strains. As a result, their CD4 counts start out lower and decline more rapidly than other people newly diagnosed with HIV

Discovery of novel anti-HIV antibody function: binding of viral particles to cell surface

HIV particles (yellow) accumulate on the surface of infected cells (purple). Color scanning electron microscope image. Stephane Fremont, Jeremy Dufloo, Arnaud Echard, Timothee Bruel, Olivier Schwartz, Jean-Marc Panaud, Institut Pasteur

A team from the Pasteur Institute, CNRS, The Vaccine Institute (VRI) and the Sorbonne University of Paris has discovered the new function of anti-HIV-1 antibodies by applying cutting-edge microscopy techniques to virus culture in vitro. Scientists have found that certain antibodies known to effectively target the HIV-1 envelope (Env) protein prevent infected cells from releasing viral particles, thereby preventing transmission of the virus. Antibodies are y-shaped, allowing them to attach themselves to or directly to infected cells and virus particles. This chain of antibodies and virus particles prevents the virus from spreading. These findings suggest that these powerful antibodies exhibit different antiviral activities in addition to neutralization. The study is published in Nature Communications February 2, 2022.

Broadly neutralizing antibodies (bNAb) targeting viral envelope (Env) proteins have great potential for the treatment of HIV-1. They were first discovered in rare patients whose serum suppressed multiple HIV strains. These antibodies exhibit a variety of antiviral activities. In addition to neutralizing the virus, that is, preventing it from infecting new cells, they also kill infected cells. Therefore, they are called pluripotent molecules. It is necessary to fully understand the range of these antiviral activities in order to use existing antibodies more effectively or to refine selection criteria for new antibodies. In addition, further study of the versatility of anti-HIV-1 antibodies could help us better understand the role that antibodies play in dealing with other viral infections.

Initially, the team from the Pasteur Institute, CNRS, VRI and Sorbonne tried to determine whether antibodies could prevent infected cells from producing virus particles. To do this, they cultured CD4 T cells (the natural target of HIV) in vitro with various antibodies for 24 hours. They then measured the number of virus particles produced by the cells in the culture medium as well as the number remaining in the cells. As a result of these experiments, the scientists were able to show that certain antibodies increased the number of viruses in cells but reduced the number of viruses in the culture medium. This intriguing finding led them to believe that certain antibodies block the release of virus particles rather than preventing their production.

To test the theory, scientists used various microscope techniques to watch cells produce virus particles. They initially examined the cells with a fluorescence microscope, a technique used to distinguish viral proteins. This allowed them to show that infected cells accumulate large amounts of mature viral proteins. This finding suggests that intact virus particles accumulate in cells. To determine the exact location of the virus particles, the scientists then used a scanning electron microscope to look at the surface of the infected cells. “Using this approach, we observed that these antibodies (bNAb) promote the accumulation of virus particles on the cell surface, forming clusters and highly atypical structures (see figure),” commented Timothee Bruel,

Next, the scientists combined transmission electron microscopy with immunogold markers. This allowed them to show that the antibody inserts itself between the virus particle and the infected cell, forming chain-like clusters. Subsequent experiments with mutated antibodies showed that the y-shape of the antibody formed this cluster structure. Their arms are capable of attaching two or one viruses to an infected cell membrane, and their attachment sites are strong enough to trigger this phenomenon.

“We have shown that only the most powerful antibodies bind virus particles to the surface of infected cells. The captured virus particles can no longer infect new cells, “concludes Olivier Schwartz, co-author of the study and head of the Division of Viruses and Immunity at the Pasteur Institute.

This work revealed novel antiviral activity that broadly neutralizes anti-HIV-1 antibodies. It deepens our understanding of how these antibodies work and explains their efficacy in clinical trials. Scientists are now studying antibodies against other viruses, including SARS-COV-2, to see if they also inhibit viral transmission by this mechanism.