Tag Archives: antibodies
Some people have developed dangerous blood clots in the brain after receiving the corona vaccination with the AstraZeneca preparation The University Medical Center Greifswald in Germany has now broken down the likely cause of the blood clots. According to Andreas Greinacher, he and his team found special antibodies in the blood of those affected, which are directed against the body’s own blood platelets. These cells play an important role in blood clotting. The antibodies activate the platelets: they clump together, as they normally do to close a wound, and thus form blood clots. The basic problem is therefore an autoimmune reaction.
In Germany, 13 cases of sinus vein thrombosis were reported shortly after an AstraZeneca vaccination, all of which were associated with a lack of blood platelets, i.e. a so-called thrombocytopenia. Around 1.6 million people in Germany were vaccinated. According to Greinacher, the problems that arose shortly after the vaccination are similar to a long-known complication with the administration of another agent, heparin-induced thrombocytopenia, or HIT for short. There, too, antibodies activate platelets so that clots form. In both cases the symptoms appear within 5 to 14 days after administration of the preparation. Greinacher therefore emphasized that the flu-like symptoms that often occur on the day after the vaccination are not a warning signal that a blood clot is developing. But anyone who has a painful leg about five days after the vaccination – as a sign of a deep vein thrombosis – or a severe headache should see a doctor immediately.
The Society for Thrombosis and Hemostasis Research has already published recommendations for doctors based on the Greifswald findings. She assumes that the formation of clots in people with sinus vein thrombosis and thrombocytopenia can be stopped by giving high doses of intravenous immunoglobulins. Greinacher could not answer how reliably this therapy helps those affected. That is not his area of expertise, he said.
“We found this absolutely fascinating mechanism of our own bodies that stops the production of rogue antibodies that can cause either autoimmunity or allergies,” senior author, ANU Professor Carola Vinuesa, said. “It’s been known for years that neuritin has a role in the brain and in the nervous system but we found an abundance of neuritin in the immune system and its mechanism – which has never been described in biology. “We have shown it is one of our immune system’s own mechanisms to prevent autoimmunity and allergy and now we have the evidence, we can go on to harness that for treatment.”
The researchers say they set out over five years ago to bridge a knowledge gap on how the immune system works following an educated guess that neuritin might have a regulatory function in stopping allergies and autoimmune disease.
The study, published today in Cell, found neuritin can prevent the production of pathogenic antibodies.
“It is an incredible discovery. We saw that in the absence of neuritin there is increased susceptibility to death from anaphylaxis, highlighting its role in the prevention of life-threatening allergies,” first author, ANU researcher Dr Paula Gonzalez Figueroa, said.
For people with allergies, when the immune system overreacts to allergens – like pollen, dust or peanut butter – it produces antibodies called Immunoglobulin E, (IgE). Allergies happen when the body produces excessive IgE in response to otherwise harmless substances, leading to the release of histamine that causes allergic reactions. “We have discovered neuritin prevents excessive formation of IgE that is typically associated with some common forms of allergy and food intolerances,” Professor Vinuesa said.
Many autoimmune diseases are caused or exacerbated by antibodies that go on to destroy our own tissues and cause autoimmune diseases like lupus and rheumatoid arthritis. “There are over 80 autoimmune diseases, in many of them we find antibodies that bind to our own tissues and attack us instead of targeting pathogens – viruses and bacteria,” Dr Paula Gonzalez-Figueroa said. “We found neuritin supresses formation of rogue plasma cells which are the cells that produce harmful antibodies.”
The researchers hope the discovery will now form the basis of new treatments.
The DxTerity COVID-19 Saliva at-Home Collection Kit detects the presence of the virus but does not confirm immunity or detect antibodies. DxTerity‘s molecular-based PCR test received approval from the Food and Drug Administration last month. The test differs from the quicker and less expensive antigen tests, which use a nasal swab or throat swab to detect the virus.
A single COVID-19 testing kit is listed for $110, and a 10-pack bundle is available for $1,000.
Test takers must spit into a tube provided by the kit. The saliva sample is then inserted into a plastic bag and packed back into the box for shipment to one of DxTerity‘s laboratories certified by the Clinical Laboratory Improvement Amendments. Customers are also granted prepaid express return shipping with the test and should expect to receive results within 24 to 72 hours of sample receipt at the laboratory. DxTerity’s test is currently the only COVID-19 testing kit on Amazon.
“We have demonstrated the reliability and quality of our COVID-19 testing solution with big business and now we want to expand access to customers at home and small businesses,” said Bob Terbrueggen, founder and CEO of DxTerity, when he first announced the collaboration with the company last month. “Amazon is the perfect partner for expanding access to millions of U.S. customers.”
The test may not be valid for all travel purposes because sample collection is unsupervised, according to the product description. The Centers for Disease Control and Prevention recommends saliva specimens should be collected under supervision.
Amazon joins other retail giants in offering at-home COVID-19 saliva tests. Costco offers both regular and those approved for travel requirements to Hawaii, Bermuda and some other destinations for $129.99 and $139.99, respectively. However, the test has several dozen one-star reviews, with most complaining about delayed shipping and poor customer service from provider AZOVA.
Scientists in the UK have just recruited the first participants in the world to be part of a new long-acting antibody study. If the treatment is effective, it could give those who have already been exposed to SARS-CoV-2 protection from developing COVID-19.
“We know that this antibody combination can neutralise the virus,” explains University College London Hospitals (UCLH) virologist Catherine Houlihan. “So we hope to find that giving this treatment via injection can lead to immediate protection against the development of COVID-19 in people who have been exposed – when it would be too late to offer a vaccine.”
This might not be the first antibody treatment for COVID-19 you’ve heard of. Outgoing US President Donald Trump was given monoclonal antibodies when he came down with the disease, and in the US two different antibody treatments – casirivimab and imdevimab – received emergency approval back in November. But those antibody treatments are given to patients with mild or moderate COVID-19, who risk progressing to a severe version of the disease.
“In a clinical trial of patients with COVID-19, casirivimab and imdevimab, administered together, were shown to reduce COVID-19-related hospitalisation or emergency room visits in patients at high risk for disease progression within 28 days after treatment when compared to placebo,” the FDA explained in a press statement when the drugs were approved. This new antibody therapy, called AZD7442 and developed by UCLH and AstraZeneca, is a little different. AZD7442 is a combination of two monoclonal antibodies AZD8895 and AZD1061, which both target the receptor binding domain of the SARS-CoV-2 spike protein.
“By targeting this region of the virus’s spike protein, antibodies can block the virus’s attachment to human cells, and, therefore, is expected to block infection,” the team wrote on the US ClinicalTrials.gov website. “Amino acid substitutions have been introduced into the antibodies to both extend their half-lives, which should prolong their potential prophylactic benefit, and decrease Fc effector functionin order to decrease the potential risk of antibody-dependent enhancement of disease.”
Antibodies are little Y-shaped proteins that lock on to a particular section – called an antigen – of a virus, bacterium or other pathogen, and either ‘tag‘ it to be attacked by the immune system, or directly block the pathogen from invading our cells. Normal antibodies are produced by your body after an infection, while monoclonal antibodies are cloned in a lab and can be injected into a person already infected, to give the immune system a hand in the fight.
The researchers are hoping that AZD7442 – which is just starting the Storm Chaser study (the name for its phase 3 trial) – provides protection for those that have been exposed to the virus but do not yet have symptoms. Effectively, they’re trying to stop COVID-19 happening in the first place. “If you are dealing with outbreaks in settings such as care homes, or if you have got patients who are particularly at risk of getting severe COVID, such as the elderly, then this could well save a lot of lives,” said University of East Anglia infectious disease expert Paul Hunter.
For epidemiologists, the COVID-19 pandemic has greatly intensified their long-standing nightmare about another virus: the emergence of a new and deadly strain of flu. A universal flu vaccine, effective against any strain of the influenza virus that can infect humans, could protect us from this peril, but progress has been slow. A novel concept for one universal vaccine candidate has now passed its first test in a small clinical trial, its developers report today in Nature Medicine.
Seasonal flu vaccines induce antibodies against the “head” (slate) of the influenza surface protein hemagglutinin, but a new universal vaccine triggers antibodies (fragments of them shown in gray) that bind to the stalk (light blue) portion
“This is an important paper,” says Aubree Gordon, an epidemiologist at the University of Michigan School of Public Health who studies influenza transmission and vaccines.
The influenza virus rapidly accumulates mutations and easily “reassorts,” or swaps, genes between strains, creating variants that can dodge any past immunity people had acquired naturally or from vaccines. That’s why a new flu vaccine must be developed each year. Existing flu vaccines contain weakened or inactivated influenza viruses with a mix of hemagglutinins (HAs), the proteins that stud their surfaces. These vaccines primarily aim to trigger antibody responses against HA’s top part, or head. Genetic changes in flu viruses rarely alter most of the head. But a small part of the head does reassort, or mutate, frequently, which allows new viral strains to dodge any immune memory and forces flu vaccinemakers to prepare new formulations each year, with updated HAs.
In the trial, 51 participants received the various vaccines and their antibodies were compared with those of 15 people who received placebos. A single shot of vaccine with chimeric HA inactivated viruses, the researchers report, “induced remarkably high antistalk antibody titers.”
As the COVID-19 pandemic continues to spread across the world, testing remains a key strategy for tracking and containing the virus. Bioengineering graduate student, Maha Alafeef, has co-developed a rapid, ultrasensitive test using a paper-based electrochemical sensor that can detect the presence of the virus in less than five minutes. The team led by professor Dipanjan Pan reported their findings in ACS Nano.
“Currently, we are experiencing a once-in-a-century life-changing event,” said Alafeef. “We are responding to this global need from a holistic approach by developing multidisciplinary tools for early detection and diagnosis and treatment for SARS-CoV-2.”
There are two broad categories of COVID-19 tests on the market. The first category uses reverse transcriptase real-time polymerase chain reaction (RT-PCR) and nucleic acid hybridization strategies to identify viral RNA. Current FDA-approved diagnostic tests use this technique. Some drawbacks include the amount of time it takes to complete the test, the need for specialized personnel and the availability of equipment and reagents. The second category of tests focuses on the detection of antibodies. However, there could be a delay of a few days to a few weeks after a person has been exposed to the virus for them to produce detectable antibodies.
n recent years, researchers have had some success with creating point-of-care biosensors using 2D nanomaterials such as graphene to detect diseases. The main advantages of graphene-based biosensors are their sensitivity, low cost of production and rapid detection turnaround. “The discovery of graphene opened up a new era of sensor development due to its properties. Graphene exhibits unique mechanical and electrochemical properties that make it ideal for the development of sensitive electrochemical sensors,” said Alafeef. The team created a graphene-based electrochemical biosensor with an electrical read-out setup to selectively detect the presence of SARS-CoV-2 genetic material.
There are two components to this biosensor: a platform to measure an electrical read-out and probes to detect the presence of viral RNA. To create the platform, researchers first coated filter paper with a layer of graphene nanoplatelets to create a conductive film. Then, they placed a gold electrode with a predefined design on top of the graphene as a contact pad for electrical readout. Both gold and graphene have high sensitivity and conductivity which makes this platform ultrasensitive to detect changes in electrical signals.
Researchers around the world are developing more than 165 vaccines against the coronavirus, and 27 vaccines are in human trials. Vaccines typically require years of research and testing before reaching the clinic, but scientists are racing to produce a safe and effective vaccine by next year. But it is likeky that before the end of the summer we will know if one vaccine, at least, is efficient.
Work began in January with the deciphering of the genome. The first vaccine safety trials in humans started in March, but the road ahead remains uncertain. Some trials will fail, and others may end without a clear result. But a few may succeed in stimulating the immune system to produce effective antibodies against the virus.
Check the status of all the vaccines that have reached trials in humans, along with a selection of promising vaccines still being tested in cells or animals.
Moderna’s Covid-19 vaccine led patients to produce antibodies that can neutralize the novel coronavirus that causes the disease, though it caused minor side effects in many patients, according to the first published data from an early-stage trial of the experimental shot.
“It certainly is a good beginning,” said Betty Diamond, director at the Feinstein Institutes for Medical Research.
The results were published Tuesday in the New England Journal of Medicine. Moderna had previously released some results in a press release, but many experts said they were not sufficient to draw many conclusions. Even now, many are withholding judgment. The study, which was run by the National Institutes of Health, showed that volunteers who received the vaccine made more neutralizing antibodies than have been seen in most patients who have recovered from Covid-19. But a second injection, four weeks after the first, was required before the vaccine produced a dramatic immune response.