A technology developed at the Fraunhofer Institute for Cell Therapy and Immunology IZI enables specific, sensitive diagnostics of the dengue virus for the first time. The patented process was licensed to two companies and the corresponding antibodiessts are now on the market. This allows the four different dengue virus subtypes to be distinguished from one another, as well as the dengue virus from other closely related ones flaviviruses. These include next to the Zika– and West Nile virus, yellow fever virus and tick-borne tick-bornemeningoencephalitis-Virus. With the adaptation of the procedure to the Coronavirus SARS-CoV-2 and West Nile Virus has already started.
The specific and sensitive blood test method established at the Fraunhofer IZI is based on modified envelope proteins of the dengue virus. The number of false positive tests is greatly reduced with this technology, since cross-reactivities to the closely related flaviviruses are prevented by using specific and blocking reagents. The basis for this was researched by Dr. Alexandra Rockstroh in her PhD thesis. The virologist belongs to the team around PD Dr. Sebastian Ulbert, who heads the vaccine technologies department at the Leipzig research institute. »Since the dengue virus occurs in four different serotypes, you can become infected more than once. Once the infection has been overcome, lifelong immunity is always only available against the respective subtype. The specific detection and serological differentiation from infections with other closely related and widespread flaviviruses such as the Zika virus is now possible for the first time with the technology we have established,” explains the scientist. This is all the more important as the symptoms of dengue and Zika virus infections, for example, can be similar and make a clear diagnosis difficult. Both viruses, like other representatives of the flaviviruses, occur in partially overlapping areas.
The Fraunhofer researchers patented the diagnostic procedure and subsequently licensed it to two companies. Last year, MIKROGEN GmbH (www.mikrogen.de), based in Neuried, Bavaria, launched an immunoblot test, i.e. a rapid test in strip format. Analytik Jena AG (www.analytik-jena.de) from Thuringia developed an ELISA (Enzyme-linked Immunosorbent Assay) test together with the subsidiary AJ Roboscreen GmbH from Leipzig. These tests are widely used in laboratory diagnostics. They are based on an interaction of antigen and antibody as well as an enzymatic color reaction.
The World Health Organization (WHO) quoted in its most recently updated in early March 2020 fact sheet a study that estimates 390 million dengue infections per year, 96 million of which manifest clinically. The dengue virus is transmitted by mosquitoes. An infection leads to a high temperature, headache and body aches. Those affected usually recover within a few days, but an infection can also lead to serious complications or even death. To date, there is no specific antiviral therapy for the treatment of dengue virus infections. However, in addition to preventing mosquito bites, a vaccine is available in many of the countries where the virus is endemic. However, this is only permitted for certain groups of people and after a dengue infection has already been overcome.
The researchers at the Fraunhofer IZI are also focusing on the West Nile virus for another application of the diagnostic method developed. Just like dengue, a tropical pathogen, the spread of which in Europe is being promoted not only by climatic changes, but also by the fact that native mosquitoes can also become carriers. The scientists are currently in the process of applying the knowledge they have gained about flaviviruses to the currently pandemic coronavirus SARS-CoV-2. These enveloped RNA viruses are also present in different subtypes. PD dr Sebastian Ulbert and his team are researching corresponding antigens, which should then improve the specificity of corona antibody tests.
Alexandra Rockstroh »Development of procedures for the specific, serological diagnosis of dengue and Zika-Virus infections with modified Envelope proteins«
Vaccine Technologies Working Group
Source: Fraunhofer IZI press release from May 19.05.2020, XNUMX