Development and evaluation of a high-sensitivity RT-PCR lateral flow assay for early detection of HIV-1 infection

Early diagnosis of HIV-1 is crucial to minimize transmission, morbidity, and mortality, particularly for neonates with developing immune systems. This study aimed to develop and evaluate a simplified, high-sensitivity assay for early HIV-1 detection before seroconversion. The assay utilizes reverse-transcription-polymerase chain reaction (RT-PCR) to amplify the HIV-1 RNA protease gene. Digoxigenin (dig)-labeled forward, and biotin-labeled universal reverse primers are used, generating digoxigenin-amplicon-biotin (DAB) products. These products are detected using a lateral flow assay (LFA) containing a conjugated pad with colloidal gold-labeled 6-histidine tagfused maltose-binding protein-monomeric streptavidin (6HISMBP-mSA-CGC). Anti-dig monoclonal antibody (mAb) and biotinylated-BSA are immobilized in the test and control line zones, respectively. Five plasma samples with known viral load (VL) were used to simulate the efficacy of early HIV-1 detection. RNA extracted from these samples was amplified by RT-PCR using the labeled primers, and DAB products were examined on agarose gel electrophoresis and LFA. RTPCR from diluted clinical samples yielded visible DNA bands in agarose gel electrophoresis, consistent with positive LFA results. Conversely, negative samples only displayed the control line on LFA. This assay exhibited a limit of detection (LOD) of 82.29 RNA copies/mL, comparable to other nucleic acid amplification tests (NAATs). This novel technique provides a highly sensitive assay for early HIV-1 diagnosis, even with low VL, making it suitable for resource-limited settings.