NUEVA PLATAFORMA ISOTERMICA PARA EL DIAGNOSTICO DE SARS-CoV2

BORIO CRISTINA; BERGIER JULIAN; LUCAS RIPOLL; NUGNES VICTORIA; BILEN MARCOS; DANIEL GHIRINGHELLI

Encuentro; XL Reunión Científica Anual SAV 2020; 2020

Most of the molecular diagnostic methods require a first step, which is the purification of nucleic acids. At the beginning ofthe SARS-CoV-2 pandemic, there were incremental needs around the world for optimized kits for RNA purification, resultingin shortages in the provision of these inputs. In this context, PBL developed a purification kit optimized for the purification ofviral RNA, called PURO Virus. The kit comes in two variants: one for manual operation and the other for use in automatedsystems, and both variants are used both in the state and private sphere. Regarding diagnosis, the UNQ laboratory developedan isothermal in vitro nucleic acid amplification method called ELA (Easy Loop Amplification). This method is a modificationof LAMP, which uses fewer primers and where the specificity is additionally ensured through the use of a labeled probe.Additionally, the ELA method uses a thermostable DNA-dependent DNA polymerase called Bfo that had been developed inPB-L. Bfo is a rational in silico design based on molecular information from an Argentine isolate of a mesophilic bacterium.In the genetic construction, the characteristics for an adequate in vitro activity ?both polymerase and chain displacement? havebeen optimized. The ELA method has already been tested for the detection of Chlamydia trachomatis DNA and as RT-ELAfor the detection of RNA of the different Dengue types. When the SARS-CoV-2 expanded to all the world and cases began inour country, we formed a partnership between the National University of Quilmes, the National University of San Martín, andthe Biotechnology companies Productos Bio-Lógicos SA and Chemtest Argentina SA. The central objective of this partnershipwas the rapid development of a POC (Point of Care) system for the diagnosis of COVID-19. In this way, ELA-Chemstriparises, where the amplification of the target is carried out by RT-ELA and the visualization of the result by GenCap, a methodderived from NALFIA (Nucleic Acid Lateral Flow ImmunoAssay). The current version of ELA-Chemstrip is of the monoplextype, having to work with two reaction tubes and two test strips; the viral target is evaluated in a tube and an endogenouscontrol in the other. The product has been approved by ANMAT and has very-good sensitivity and specificity. We are currentlyworking on the development of a multiplex version in which the viral target and the endogenous control are co-amplified inthe same tube, and the results are visualized using a single test strip. In parallel, we continue working on new applications anddevelopments.