Horse plasma can be used to treat Covid-19 patients, says ICMR study
Antibody-rich plasma obtained from horses can be used to treat patients infected with Covid-19, according to an Indian Council of Medical Research (ICMR) pre-print study, following which the apex medical research body has received regulatory approval to conduct clinical trials using the equine plasma on humans.Updated: Oct 09, 2020, 06:00 IST
Antibody-rich plasma obtained from horses can be used to treat patients infected with Covid-19, according to an Indian Council of Medical Research (ICMR) pre-print study, following which the apex medical research body has received regulatory approval to conduct clinical trials using the equine plasma on humans.
The study was published on Research Square.
In the study, 10 healthy horses between the ages of four and 10 years were injected with inactivated Sars-CoV-2 antigen subcutaneously (under the skin) at the Hyderabad-based Biologicals E Ltd, and after 21 days of immunisation, their plasma samples were tested. Sars-Cov-2 is the virus that causes Covid-19.
The plasma had Covid-19-specific high-quality antibodies with virus neutralising capacity, which is ideal for preventing infection. The results are in line with other studies on equine antisera that reported the generation of a high level of antibodies in horses against the receptor binding area of the virus’s spike protein. A receptor-binding domain is a key part of a virus located on its spike domain that allows it to dock to body receptors to gain entry into cells and lead to infection. It is safe, and can be prepared in bulk at a low cost, the ICMR study shows.
“With Biologicals E we have developed horse sera which may be considered. We have completed some animal studies where we have a predictive dose… we have got clearance for a clinical trial,” said Dr Balram Bhargava, director general, ICMR.
The virus strain was isolated from the throat and nasal swab specimens of aCovid-19 positive patient at the maximum containment facility of ICMR-National Institute of Virology, Pune. Diseases for which equine sera has previously been tried include many viral and bacterial infections such as rabies, hepatitis B, vaccinia virus, tetanus, botulism and diphtheria. “…This study suggests promising efficacy and therapeutic potential of equine hyper immune sera against Sars-CoV-2. The quality control assessments of the different batches proved to have consistent nAb (antibody) titres (volume of antibodies produced)… that can demonstrate consistent and high neutralization activity,” says the paper.
“Further, in-vivo testing for efficacy of this indigenously developed, cost effective product will pave the way to clinical evaluation. Additionally, being a donor independent method, this may prove as an efficient alternative to convalescent plasma for treatment of Covid-19 patients,” the researchers say.
Virologists agree that animal antisera are a good option. “It does have advantages over convalescent plasma as the quality of convalescent plasma is entirely donor dependent. The quality will be different from one donor to the other. Use of antibodies that have been raised in large animals is common, and has worked successfully in the past. If an animal study has shown promise against Sars-Cov-2, then it is good news,” said T Jacob John, former head of the virology department at the Christian Medical College in Vellore, Tamil Nadu.
Animal-derived plasma can help overcome the challenge of limited availability of convalescent plasma from recovered patients, and find a cost-effective alternative to monoclonal antibodies (man-made proteins that act like human antibodies in the immune system) that are laborious and expensive to generate