The antigenic epitope of HIV MPER derived from gp41 was generated in an expression plasmid by (GenScript Co, Piscataway, NJ). This peptide was used as a positive control for the ELISA assays. Peptides were .98% pure as indicated by analytical highperformance liquid chromatography. Peptides were dissolved in 100% DMSO at a concentration of 10 mM and stored at 220uC until use. 