Figures & data
Figure 1. Scheme of peptides that flank and span the CMV Antigenic Determinant 2 (AD-2) region based on a series of overlapping peptides. The peptide labels as well as the amino acid spanned by each within the AD169 gB are shown. The minimal linear epitope recognized by AD-2 specific mAbs is underlined, and flanking regions identified in some literature reports as included in the AD-2 epitope are in boldface.
Figure 2. Serum neutralizing titers (NT50) in (A) epithelial (ARPE-19) and (B) fibroblast (MRC-5) cells vs ELISA titers (AD-2 peptides 5, 6, and 7) from the epidemiological study. Correlations were highly significant (p ≤ 0.01), but most of the variability in neutralization is not predicted by AD-2 peptide ELISA (R2 = 0.06, 0.07).
Figure 3. Binding ELISA responses to AD-2 peptides at day 69 (A), AD-2 peptides at day 146 (B), and AD169 virions at day 146 (C). Mice (n=10) were immunized with CRM-conjugated AD-2 peptides at days 0, 21, 48, and 110, and boosted with AD169 virions at day 138. Sham vaccine is a saline buffer with alum but no peptide. Sham vaccinated animals were tested against a pool of all AD-2 peptides. All AD-2 peptides were immunogenic and this was sustained and enhanced after boosting with AD169 virions. Antibody titers to AD169 were comparatively low. Error bars represent the SEM.
Figure 4. Neutralizing titers (NT50) in (A) ARPE-19 cells, (B) MRC-5 cells at day 146 from sera of mice immunized with CRM-conjugated AD-2 peptides at days 0, 21, 48, and 110, and boosted with AD169 virions at day 138. Even with the robust binding titers to AD-2 peptides (), no significant neutralization due to immunization with AD-2 was observed (i.e., neutralizing titers of AD2-vaccined and sham-vaccinated mice were generally similar). Error bars represent the SEM.
Figure 5. ELISA from rabbits immunized with CRM-conjugated AD-2 peptides, or gB with an oil-in-water adjuvant. (A) Time course of immune response, group geometric mean and standard error; and (B) individual rabbits' titers at the peak response (week 10). The lower limit of detection is 1:40. None of the AD-2 peptide vaccines were superior to gB/MF59 at any time after immunization.
Figure 6. Neutralizing titers (NT50) from rabbits immunized with CRM-conjugated AD-2 peptides or gB with MF59 adjuvant. (A) sera alone, (B) with added rabbit complement. The lower limit of detection is a 1:5. Horizontal bars represent the geometric mean of each group. None of the AD-2 peptide vaccines were superior to gB/MF59.
