• The Jurkat S-flow cytometry test features the use of the complete S protein displayed in its native conformation on the cell membrane of Jurkat cells.
• Results are collected by flow cytometry, an advanced technology with superior performance and an ultra-wide dynamic range.
• The test affords unmatched specificity and sensitivity (99% agreement with neutralization assays).
• The test is especially suited as a confirmatory test for the vaccinated population, although it can also be used to interrogate the presence of antibodies after natural infection.
• Only a few drops of blood are needed which can be collected with a painless finger prick.
• The test will be available as soon as February 15^th and will be compatible with self-collected capillary blood through an accompanying self-collection kit.

 

Vitro S.A., the Spanish corporate group developing, manufacturing, and distributing devices, software, and reagents for in-vitro diagnostics (IVD) is releasing a new diagnostic test for the detection of antibodies against SARS-CoV-2, the virus that causes Covid-19, with unprecedented analytical and clinical performance: the Jurkat S-flow cytometry test.

This novel antibody detection test has been developed by the research team led by Dr. Balbino Alarcón at CSIC (Consejo Superior de Investigaciones Científicas). It only needs a few drops of blood and achieves a 99% sensitivity as compared with neutralization assays.

Jurkat cells, which are grown in suspension and are optimal for flow cytometry studies, were engineered to produce and expose the SARS-CoV-2 Spike protein (S protein) on their cell membrane. The viral S protein, which was confirmed to be in its native trimeric form and to induce syncytia formation, is produced in the cells in parallel to a control protein that is also exposed on the surface of Jurkat cells. After incubating the patient’s serum with a cocktail of fluorescent antibodies against the control protein and anti-S immunoglobulins, , the cells are acquired in the flow cytometer and the resulting data is processed using the control protein for data correction and normalization.

As detailed in the ahead-of-print on-line publication in EMBO Molecular Medicine (Horndler L et al, published on-line on January 20^th, Dr. Alarcón’s team performed a thorough validation of this technology, comparing it to several other serological tests. For this purpose, Dr. Alarcón’s team used different sample sets (more than 600 samples overall) comprising serum samples covering the entire clinical spectrum (from asymptomatic to severe disease), and sera collected from donors before the Covid-19 pandemic as negative controls. The Jurkat S-flow cytometry test showed an exquisite specificity in sera from pre-Covid-19 donors (100%) proving to be the one test able to detect the highest number of positives, and calling clear positives where other methods fail to yield a concise result (i.e. results within the “gray area”). It also showed a nearly perfect correlation with neutralization assays (99%), which evaluate the capacity of the tested sera to decrease or prevent the infection of ACE2-expressing cultured cells when confronted with lentiviral particles coated with the SARS-CoV-2 S protein (i.e. pseudotyped virus). In addition, the Jurkat S-flow cytometry test proved to be compatible with serum from capillary blood.

 

The test will be offered by Vitro S.A. as a reliable option for those who wish or need to confirm that they have developed antibodies against the virus after vaccination, which could be key for a safe return to their routines. Also, it will help decide vaccination priority.

Vitro S.A. will also release and accompanying self-collection kit that will be available at the network of medical centers managed by Vitro S.A.’s partner Recovid Solutions. Capillary blood self-sampling facilitates testing — helping increase testing rate — and contributes to reducing the risk of disease transmission by avoiding the need of venopuncture, therefore preventing the exposure of healthcare workers. Once dropped off at the medical centers the samples will be sent to Vitro S.A. laboratories in Granada where the Jurkat S-flow cytometry test is conducted by trained laboratory staff with state-of-the-art technology and in compliance with the highest quality standards.

In Javier Fernandez’s (Vitro S.A.’s CEO) words: “our company is once again at disposal of science and innovation in the restless fight against Covid-19. This novel test will prove to be key to decide priority of vaccination and to allow an effective monitoring of vaccination results, which will get us closer to the end of the pandemic”.

Collaborating in the fight against the pandemic

This new test reaffirms Vitro’s continued commitment to the fight against the coronavirus pandemic. As part these efforts Vitro launched the IVD test “Respiratory Flow Chip” this past July. The test simultaneously detects 21 respiratory pathogens: three species of bacteria and 18 virus species including SARS-CoV-2 and.

Also, Vitro recently validated clinically its RNA extraction kit and its RT-qPCR SARS-CoV-2 test, which together with the traceability software OpenVTR — also developed by Vitro — enable the use of Opentrons robots, many of which are available at the largest hospitals in Spain.

In addition, Vitro has also released a IVD kit for detecting Influenza A (FluA), Influenza B (FluB) and SARS-CoV-2 in a single Real Time RT-qPCR Multiplex One-step reaction.