He N-terminal residue of gp41) using the overlapping PCR method.Cell-Based Enzyme-Linked Immunosorbent Assay (ELISA)A sensitive cell-based ELISA with high temporal resolution was developed to measure the binding of antibodies to HIV-1 envelopeMetastable Activation of HIV-1 Envglycoprotein trimers expressed on cells. COS-1 cells were seeded in 96-well plates (2.46104 cells per well) and transfected