Super-potent antibodies taken from the blood of Covid-19 survivors could protect animals from being struck down badly, a study has found.
Experts discovered extremely strong antibodies which prevented hamsters getting severely unwell with the disease, when exposed to the SARS-CoV-2 virus.
Academics at Scripps Research, in San Diego, say the antibodies can be cloned in the lab and be mass-produced, if they are proven to fight the virus.
Antibodies are made by the immune system in response to an infection, helping the body to destroy the pathogen if exposed again in the future.
Questions remain over whether Covid-19 survivors develop any immunity once they recover from the disease.
But antibodies are a promising line of therapeutics because they can be developed much quicker than vaccines, offering a short-term solution.
Administered in doses — like a vaccine, scientists say antibodies could give humans the ability to avoid being struck down by the disease.
Antibodies made in the laboratory to mimic natural antibodies have been used in the treatment of a huge range of conditions, including arthritis, Crohn’s and Ebola.
Scientists all over the world are looking at monoclonal antibody therapy for the new coronavirus but there are few currently in clinical trials.
Super-potent antibodies taken from the blood of Covid-19 survivors can completely protect animals from catching the infection. (Stock of antibodies attacking the coronavirus)
Dr Thomas Rogers, one of the authors behind the antibody breakthrough, described the research as a ‘tremendous collaborative effort’.
He added the team was ‘now focused on making large quantities of these promising antibodies for clinical trials’.
Researchers took blood samples from 17 patients who had recovered from mild-to-severe bouts of Covid-19.
They looked for antibodies, which are proteins produced by the immune system in response to the presence of a foreign substance, like the coronavirus.
They then tested whether antibody-rich blood could actually block the coronavirus from infecting ‘test cells’ that replicate human cells in a petri dish.
WHAT IS MONOCLONAL ANTIBODY THERAPY?
Monoclonal antibody therapy is a form of immunotherapy that uses monoclonal antibodies (mAb).
It’s given as an injection under the skin or through a drip into a vein.
The treatment works in many different ways. It can work in a vaccine-like way, protecting a patient from severe disease, or can help to stimulate the patient’s immune system to attack antigens.
Hybridoma technology is one method for producing large numbers of monoclonal antibodies – identical antibodies that are clones of a unique parent cell.
The process starts by injecting an animal, such as a mouse, with an antigen that provokes an immune response.
B cells produces antibodies that bind to the antigen. These antibody producing B-cells are then harvested and used to culture more antibodies.
The monoclonal antibodies are screened against their ability to work, with initial experiments in animals.
Major technological advances have made the discovery and development of mAb therapies quicker and more efficient, deriving the antibodies from humans and not animals.
Scientists can create a mAb that is specific to almost any antigen, and are working on one for the coronavirus.
The spike protein on the SARS-CoV-2 virus is the primary target being explored for potential Covid-19 monoclonal antibodies.
The aim is that by targeting the spike protein, the antibody will be able to neutralise the SARS-CoV-2 virus, therefore stopping it from infecting healthy cells.
A particularly interesting avenue is giving them to people who aren’t infected yet as a preventative tool. If the antibodies are potent and long-lasting enough, they could provide sufficient protection for a period or time before a vaccine is found.
Research and development is underway to create antibodies for diseases such as rheumatoid arthritis, multiple sclerosis, Alzheimer’s disease, and different types of cancers.
But many are already in use both in the US and UK.
Since 2008, 48 new mAbs have been approved, contributing to a total global market of 61 mAbs in clinical use at the end of 2017, according to the US FDA.
The role of antibodies is to latch on to foreign substances like the coronavirus and mark it for other immune cells, such as T-cells, to kill.
Antibodies are considered one of the last lines of defence in the immune system, called the adaptive immune system, and can take a number of days to come into action.
They are triggered into action by B cells, which tell the antibodies which specific pathogen they have to look for.
The researchers isolated more than 1,000 B cells from three donors which produced distinct anti-SARS-CoV-2 antibodies.
They obtained the antibody gene sequences from these B cells so that they could mass-produce the antibodies in the laboratory.
By screening these antibodies individually, the team identified a handful that could ‘neutralize’ the virus in the test cells which replicate those found in the human body.
Neutralizing antibodies are able to kill the virus themselves, rather than just tagging it for other immune cells to attack.
The findings suggest not everyone has these neutralizing antibodies with ‘outstanding potency’.
One antibody was able to protect hamsters against severe Covid-19, according to the findings published in the journal Science, when compared with an antibody for dengue virus.
The researchers used the hamster’s weight as an indicator of disease progression. If the hamsters maintained their weight, it indicated they did not get as sick.
Those given a dose of dummy antibodies lost 13 per cent of their weight, compared to hamsters given the highest dose of the super-potent coronavirus antibody, who lost no weight.
Five days after infection, roughly two days before hamsters typically recover from an infection, the researchers measured the levels of viral load in the animals’ lung tissue.
The findings corroborated with weight loss, showing the hamsters treated with the Covid-19 antibodies fared better.
The authors of the paper said the success of potent antibodies in hamsters gives merit for human trials.
But the team acknowledged there will be differences in how humans respond to the treatment, compared with animals.
Dr Dennis Burton, another one of the researchers, said: ‘The discovery of these very potent antibodies represents an extremely rapid response to a totally new pathogen.’
If further safety tests in animals and human trials go well, the antibodies could be used in clinical settings as early as next January, the researchers say.
‘We intend to make them available to those who need them most, including people in low- and middle-income countries,’ said study co-author Dr Elise Landais, a principal scientist at IAVI, a nonprofit scientific research organisation involved in the work.
In principle, injections of potent antibodies could be given to patients in the early stage of Covid-19 to stop the disease from progressing and becoming severe.
AstraZeneca’s chief executive, Pascal Soriot, said an antibody treatment being developed is ‘a combination of two antibodies’ in an injected dose
They could also be given as vaccine-like protection to prevent the coronavirus from infecting cells in the first place.
This may be particularly useful for healthcare workers, elderly and vulnerable people — all of whom are at significant risk of Covid-19.
Scientifically engineered antibodies, called mAbs, are used in the treatment of other diseases and have become increasingly popular over the past 25 years.
Monoclonal antibody therapy has been successful against Ebola and the pneumonia-causing respiratory syncytial virus, commonly known as RSV.
The breakthrough follows AstraZeneca revealing it was working on an injection with cloned antibodies that could be ready next year.
Chief executive Pascal Soriot told The Sunday Telegraph the therapy being made is ‘a combination of two antibodies’ in an injected dose.
The dose which allows the body to fight Covid-19 could prove hugely beneficial for those in the early stages of infection, according to the Cambridge-based firm.
It would essentially give a person the chance to fight the virus quickly so that it does not have the ability to develop into severe disease.
AstraZeneca is the same firm which has already started to manufacture the Oxford University Covid-19 vaccine, which is undergoing human trials.