Inhibition of viral infection by LTNP sera and vaccinated mice sera. Viral infection was measured after treatment with LTNP sera and sera from mice vaccinated with a peptide containing an identified HIV neutralization epitope. A (left graph) demonstrated the MT2 cell syncytia formation after infection by cell free H9MN virus. As shown in the figure, sera from patient LTNP-2, LTNP-3, LTNP-4, and LTNP-5 (patient 25) significantly inhibited the syncytia formation (p < 0.05). B (right graph) shows antisera from the vaccinated mice (with the AC peptide) binding to gp41, and comparing this binding titer to the positive control sera of patient 25 and the negative control sera of mice vaccinated with the beta amyloid peptide.