Figure 2.
Delivery of Ad-RSVtk vector to the eye does not induce an adenovirus cytotoxic T lymphocyte (CTL)–specific immune response. (a) Presence of adenovirus-specific CTLs in the peripheral blood of four patients who received eye injections of Ad-RSVtk vector, and a patient diagnosed with adenovirus conjunctivitis was measured by enzyme-linked immunosorbent spot assay. PBMCs collected before the injection or at the time of diagnosis, and cells collected 2 weeks after the first acquired sample were challenged with an immunogenic hexon peptide common to all known serotypes of human adenovirus or PBMCs alone as a control (data not shown). None of the patients who received Ad-RSVtk vector injection had a significant increase in adenovirus-specific CTLs at 2 weeks after injection, whereas the patient with adenoviral conjunctivitis had a significant increase in adenovirus-specific CTLs at 2 weeks after diagnosis. This adenovirus conjunctivitis patient had not received steroid treatment. (b) Comparison of the adenovirus-specific CTL response of patients 3 (inverted closed triangles) and 4 (closed diamonds) who received multiple injections of adenovirus vector. No significant increase in adenovirus-specific CTL response was observed after 1 week of either of the subsequent vector injections. Plotted data were standardized to spot-forming cells (SFCs) per 4 × 105 PBMCs. PBMC, peripheral blood mononuclear cell.