In brief, to analyze MPER presentation on selected vectors, 10 10 viral particle (VP) were boiled in Laemmli sample buffer for 10 minutes and resolved on 4 to 15% sodium dodecyl sulfatepolyacrylamide gel. The proteins were transferred to polyvinylidene fluoride membrane and staining was performed with HIV-1 gp41 monoclonal antibody (2F5) (1:1,000). Followed by secondary staining with HRP-conjugated goat anti-human antibody (1:2,000). The proteins were detected on the polyvinylidene fluoride membrane by staining with 3939-diaminobenzidine tablets (Sigma-Aldrich, St. Louis, MO).