[Selection and recombinant expression of an immunodominant B cell epitope of HIV gp41]

A novel method was designed for disease-specific B cell epitope mapping and epitope expression in E. coli. A phage library displaying random dodecamers was biopanned first with human total IgG antibodies against HIV-1, and then non-specific phages were subtracted by HIV(-) polyclonal antibodies. After three rounds of screening, the positive phages were tested in an ELISA for their reactivity with HIV(+)-IgG and HIV(-)-IgG antibodies. Phages that showed positive reactivity with HIV(+)-IgG, but negative to HIV(-)-IgG, were selected and their displayed peptides were determined by DNA sequencing. All the 13 positive clones sequenced displayed five kinds of peptides (SPKCLGKLLCAF, THQCLGKLQCGV, SCSAKFTCTTQI, KSDCSARFMCSV, DCLKQWACEWSR) that have homology to the HIV-1 gp41(602GCSGKLICTTNV613), demonstrating there is a dominant epitope in the region.