Quick and reliable diagnosis of dengue is essential to guide patients’ treatment. UFV researchers are developing a low-cost and accurate kit for immediate diagnosis of the disease. The team led by Professor Sérgio Oliveira de Paula, from the Graduate Program in Cellular and Structural Biology, developed a test with antigen obtained by yeast protein expression. The test is composed of a strip impregnated with antigen, which reacts when in contact with the blood of patients and indicates the occurrence or absence of dengue immediately.
The diagnosis is given by the immunochromatographic method and is very similar to the pregnancy test, in which changes in the strip color indicates the result. Professor Oliveira explains that the test is very simple indeed: “you just have to obtain serum from the patient, use this strip and see if it was positive or negative. The test can be conducted by anyone, anywhere. It does not need to be in a clinic nor be performed by an expert”. The researcher points out that this rapid response is necessary due to the risk of hemorrhagic dengue fever, a more serious form of the disease, which can lead to death if it is not treated quickly. Professor Oliveira also claims that this test can be produced at low cost. Therefore, it can be used for dengue diagnosis on a large scale throughout Brazil, including in remote areas.
Today, the antigens used for diagnosis of dengue in Brazil are obtained from mouse brain, “an expensive and laborious process” – explains the researcher. Diagnosis is given by the serological test MAC-ELISA, and serum is collected after the sixth day from the onset of symptoms. This period of wait before testing is necessary because it is the time the body takes to produce the antibody, which is the molecule that will allow detecting whether the individual has dengue or not.
On the other hand, the test under development in the UFV Laboratory of Molecular Immune Virology does not require such wait. When the first symptoms appear, it can already be performed. According to Professor Oliveira, this research not only proposes a new test, but also improves the test currently used for diagnosis. The researcher explains that the antigen obtained by protein expression has already been tested in the MAC-ELISA and applied in humans, with very satisfactory response.
Tetravalent subunit vaccine
Dengue is transmitted by the bite of mosquitoes of the genus Aedes and the main measure for disease control is combating this vector. However, in the rainy season, the number of vectors increases, as well as the number of cases. Aiming at the effective control of the disease, Professor Oliveira and his staff are working to produce a tetravalent vaccine against the dengue viruses. The vaccine generates a recombinant protein (with sequence of the four dengue serotypes). In addition to protein protection, the vaccine contains genetic adjuvants, which are substances that enhance the immune system and thus improve the response from individuals.
The researcher states that there are attenuated virus vaccines comercially available, but these vaccines cause many side effects. The vaccinated person presents symptoms similar to those caused by the dengue virus. It prevented these vaccines from being used. On the other hand, subunit vaccines are potentially safer, more stable, easily manageable and have shown good results against various infectious diseases. The tetravalent vaccine that is being produced at UFV against dengue virus “has few side effects and is economically viable for industrial scale production. Tests have been carried out in mice, and the responses obtained so far are promising”- says professor Oliveira.