July 19, 2021
By Annette Boyle

Aditxt Technologies Inc. enhanced its immune response test for COVID-19 by adding a high-sensitivity neutralizing antibody quantification. With the expansion, the multidimensional test, Aditxtscore, provides a comprehensive measure of the strength of an individual’s immune response to the novel coronavirus.

“Everyone’s immune response is unique to that individual,” said Aditxt CEO and co-founder Amro Albanna. “We have been studying individual immune responses to COVID-19 and COVID-19 vaccination, and we are finding that the immediacy, strength, and duration of antibody responses can vary widely based on a multitude of variables.”

The test measures levels of three antibodies – IgM, IgA, and IgG – independently of each other against three different SARS-CoV-2 antigens, giving a more complete picture of the immune response to either the virus itself or a COVID-19 vaccine. The number of antibodies of each type directed against the receptor binding domain (RBD), spike protein (S1), and nucleocapsid protein (NP) is calculated, with the level of response indicating the quality of immune protection and the source of the response. The test report shows the results of each of the nine assays.

“So, it allows us to actually differentiate who’s got a vaccination versus who’s got an infection. We can tell that because with the vaccines, they only have the spike protein and the receptor binding domain antigens,” Aditxt Senior Vice President of Laboratory Science Joseph McConnell told BioWorld. “We can easily see if somebody got an infection because he gets a nucleocapsid response that you don’t see with vaccine.”

A vaccinated individual who did not have the infection at any point would generally show elevated response of all three antibodies to the RBD and S1 antigens, but only low levels of antibodies for the NP protein. The NP antigen is not active in COVID-19 vaccines, but is present in the SARS-CoV-2 virus itself.

In contrast, an individual who had contracted COVID-19 several months prior to testing and had not been vaccinated would typically have strong IgG response to all three antigens and lower levels of IgM and IgA antibodies against the antigens. IgM and IgA develop relatively early in an infection and then fade as IgG takes on a larger role in the immune response. IgG, however, rises later but stays elevated for months or even years, depending on the infection.

“The addition of this new Aditxtscore for COVID-19 captures important data on how effective an individual’s antibodies are for inactivating the virus,” added Albanna. The nine assays are run simultaneously to give greater precision and more detail about the strength of an individual’s response against the virus.

Importance for the immunocompromised

For people with compromised immune systems, more frequent assessment of response could be beneficial. An initial test to see whether the immune system has mounted a strong response following full vaccination could inform both patient and physicians about the need for a third shot, such as Israel is currently offering for immunocompromised individuals. Later tests might indicate that neutralizing antibodies have weakened more quickly in some individuals than expected and that a booster could be in order.

Beyond those with weakened immune response, measuring the activity of neutralizing antibodies could direct public policy as well as individual decisions. “We know that the vaccines are effective for 95% of people for at least six months because that’s the way the studies were designed,” McConnell said. “But what happens after six months? We can see if they have an adequate response and are protected by neutralizing antibodies.” In that case, an individual might choose to wait for a booster that could include protection against new variants. If they don’t still have adequate protection, receiving a booster sooner would make more sense. Without testing, a more general recommendation for boosters could help ensure adequate protection for the vaccinated population, but at a higher cost.

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To support the development of Aditxtscore, the company netted $4.5 million in financing through a securities purchase agreement with an unnamed investor in January 2021. “This financing will allow us to scale Aditxtscore beyond our current planned capacity in order to meet potential demands of current and prospective channel partners,” said Albanna. “We believe the continuing increase in COVID-19 cases and availability of COVID-19 vaccines will drive a growing need for routine monitoring of an individual’s immunity status which will be crucial to moving toward a return to public normalcy.”

The Mountain View, Calif.-based company also strengthened its cash position with $3.3 million received from the exercise of outstanding warrants issued as part of a $9.6 million capital raise in September 2020. The company also registered for $100 million in mixed securities shelf offering in early July. Aditxt joined the Russell Microcap Index in late June.

In May 2021, the company said it would invest $31.5 million in a 25,000 square foot, high-capacity center to produce the Aditxtscore. The facility would bring 300 new jobs to Richmond, according to Virginia officials.