Friday, Aug 07, 2020 | Last Update : 06:53 PM IST

136th Day Of Lockdown

Maharashtra47977931637516792 Tamil Nadu2791442210874571 Andhra Pradesh1967891128701753 Karnataka158254802812897 Delhi1415311271244059 Uttar Pradesh108974634021918 West Bengal86754610231902 Telangana7525753239601 Gujarat65704485612529 Bihar6203140760349 Assam4816233429115 Rajasthan4667932832732 Haryana3779631226448 Odisha3768124483258 Madhya Pradesh3508225414912 Kerala279561629988 Jammu and Kashmir2239614856417 Punjab1901512491462 Jharkhand140705199129 Chhatisgarh10109761369 Uttarakhand8008484795 Goa7075511460 Tripura5520367528 Puducherry4147253758 Manipur301818147 Himachal Pradesh2879171013 Nagaland24056594 Arunachal Pradesh179011053 Chandigarh120671520 Meghalaya9173305 Sikkim7832971 Mizoram5022820
  Science   30 Apr 2020  Illama-derived antibodies may block coronavirus entry into host cells: Study

Illama-derived antibodies may block coronavirus entry into host cells: Study

Published : Apr 30, 2020, 10:33 am IST
Updated : Apr 30, 2020, 10:33 am IST

According to the study, published in journal Cell, this protein, called the spike protein, allows the coronavirus to break into host cells

 Representative Image. (PTI Photo)
  Representative Image. (PTI Photo)

Houston: Molecules derived from the immune system of the South American mammals illamas may block the entry of the novel coronavirus into host cells, according to a study which could lead to a potential avenue for COVID-19 treatment.

Researchers, including those from The University of Texas (UT) at Austin in the US, have linked two copies of a special kind of antibody molecule produced by the llama immune system to create a new type that binds tightly to a key protein on the novel coronavirus, SARS-CoV-2.


According to the study, published in the journal Cell, this protein, called the spike protein, allows the coronavirus to break into host cells.

The findings, according to the researchers, indicate that the Illama-derived antibody may block viruses with this spike protein from infecting cells cultured in the lab.

"This is one of the first antibodies known to neutralise SARS-CoV-2," said study co-author Jason McLellan from UT Austin.

The scientists said they are preparing to conduct preclinical studies in animals such as hamsters or nonhuman primates, with the goal of developing a treatment that would help people soon after infection with the virus.


While vaccines have to be given a month or two before infection to provide protection, the researchers said antibody therapies can achieve this immediately.

"With antibody therapies, you're directly giving somebody the protective antibodies and so, immediately after treatment, they should be protected," McLellan said.

"The antibodies could also be used to treat somebody who is already sick to lessen the severity of the disease," he added.

According to the researchers, this would be especially helpful for vulnerable groups such as elderly people, who mount a modest response to vaccines, meaning that their protection may be incomplete.


The scientists explained that the strategy can be made to work since the immune system of illamas produce antibodies similar to that of humans.

When llamas' immune systems detect foreign invaders such as bacteria and viruses, these animals produce two types of antibodies.

One of these is similar to human antibodies, and another that's only about a quarter of the size, the researchers said.

They added that the smaller ones, called single-domain antibodies or nanobodies, can be nebulised and used in an inhaler.

"That makes them potentially really interesting as a drug for a respiratory pathogen because you're delivering it right to the site of infection," said Daniel Wrapp, study co-author from UT Austin.


The scientists extracted the antibodies for the study from a 4-year-old illama, Winter, living on a farm in the Belgian countryside along with approximately 130 other llamas and alpacas.

In 2016, when Winter was about 9 months old, the researchers were studying two earlier coronaviruses -- SARS-CoV-1 and MERS-CoV.

In a process similar to humans getting shots to immunise them against a virus, the researchers injected the illama with stabilised spike proteins from the coronaviruses over the course of about six weeks.

They then collected a blood sample and isolated the antibodies bound to each version of the spike protein.

According to the researchers, one of these antibodies, VHH-72, showed promise in stopping a virus with spike proteins from SARS-CoV-1 from infecting cells cultured in the lab.


"There wasn't a big need for a coronavirus treatment then. This was just basic research. Now, this can potentially have some translational implications, too," Wrapp said.

The scientists then engineered a new antibody that showed promise for treating the current SARS-CoV-2.

According to the researchers, the engineered antibody involved linking two copies of VHH-72 that bound more effectively to the novel coronavirus spike protein.

They said the engineered protein can bind strongly to viruses displaying spike proteins from SARS-CoV-2 in cell cultures, adding that this is the first known antibody that neutralise both SARS-CoV-1 and SARS-CoV-2.


Tags: molecules, illamas, coronavirus, covid-19 treatment., novel coronavirus, host cells