Neutralizing antibodies isolated from COVID-19 patients can quash SARS-CoV-2

By Angela Betsaida B. Laguipo, BSNReviewed by Emily Henderson, B.Sc.Jul 23 2020

Antibodies are formed to fight off an infection by neutralizing disease-causing microorganisms. Scientists across the globe are racing to study how antibodies can help suppress the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes the coronavirus disease (COVID-19).

Image Credit: David Ho / Columbia University Irving Medical Center

A team of researchers at Columbia University Irving Medical Center have isolated antibodies from COVID-19 patients, which are found to be the strongest ones that can neutralize the novel coronavirus. The collection of antibodies that is more potent, robust, and diverse compared to other antibodies found, can be developed into treatments to combat the actively spreading infection.

The discovery and development of virus-neutralizing monoclonal antibodies could be a valuable approach to treat and prevent infection by the SARS-CoV-2. The team reported the isolation of 61 coronavirus-neutralizing monoclonal antibodies from five infected patients who had been admitted due to severe COVID-19 disease.

In the study, which was published in the journal Nature, the team reports that among the 61 antibodies isolated, 19 antibodies potently neutralized the SARS-CoV-2 virus in vitro, wherein 9 manifested robust potency and efficacy.

What are antibodies?

The body searches for and destroys potentially harmful invaders, and antibodies are key players in that fight. Antibodies are specialized, Y-shaped proteins that bind like a lock-and-key to foreign invaders, including bacteria, viruses, parasites or fungi.

Antibodies are vital components of the immune system that circulates in the blood. They roam around to recognize foreign substances and neutralize them. When antigens or foreign invaders attack the body, antibodies are formed to detect them specifically. From there, antibodies continue to circulate in the blood, protecting future exposures.

Antibodies provide significant protection

One of the responses of the body to an infection is to create antibodies. These antibodies are designed to locate and kill antigens or viruses that enter the body. Though a string of drugs and vaccines are underway, they may not be ready for many months.

In the study, the researchers confirmed that SARS-CoV-2 neutralizing antibodies produced by patients with COVID-19 could be utilized to treat other patients, or even to protect people who were exposed to the virus. Furthermore, the time needed to approve and develop antibodies for use as a treatment will take less than traditional drugs and vaccines.

Using antibodies as treatment includes the use of convalescent serum from those who have recovered from COVID-19. In convalescent serum transfusion, the serum comprises a multitude of antibodies, but every patient manifests a diverse immune response. This means that the antibody-rich plasma transfused into one patient may be distinct from the plasma given to another, with varying strengths and concentrations of neutralizing antibodies.

Sicker patients produce stronger antibodies

The researchers worked on determining and isolating antibodies since March and had easy access to blood samples from patients who had moderate and severe COVID-19 disease. These patients were admitted to Columbia University Irving Medical Center in New York City, the epicenter of the pandemic in the United States.

Based on their findings, the team discovered that though many patients infected produce large amounts of antibodies, the quality of the antibodies differs. For instance, those who developed the severe disease, such as those needing mechanical ventilation, produced more potent and robust neutralizing antibodies compared to those who developed a mild and moderate illness.

“We think that the sicker patients saw more virus and for a longer period, which allowed their immune system to mount a more robust response. This is similar to what we have learned from the HIV experience,” Dr. David Ho, scientific director of the Aaron Diamond AIDS Research Center and professor of medicine at Columbia University Vagelos College of Physicians and Surgeons, said in a statement.

Study implications

Since the team has found various antibodies, including new ones that were never reported before, they believe these antibodies are potent enough to combat the coronavirus pandemic. Furthermore, the antibodies are not hard to generate by the immune system, which will aid in the development of new and effective vaccines.

The study also revealed that those who had severe COVID-19 disease are more likely to have strong immunity against the virus. However, the team emphasizes that more research is needed to answer the questions about how long the immunity against SARS-CoV-2 infection will last.

With the vast spread of the virus, antibody treatments, vaccines, and drugs are needed to combat the pandemic. So far, the number of confirmed cases has topped 15.17 million, with more than 622,000 deaths. The United States remains as the nation with the highest case toll, reaching 3.96 million, while Brazil has reported more than 2.22 million confirmed cases. India and Russia follow with more than 1.19 million and 787,000 cases, respectively.