FIG. 4.

Antibody-dependent enhancement of ADV infection for K562 cells mediated by antibodies prepared against ADV VP2 peptides. Dilutions of the indicated rabbit polyclonal and murine monoclonal antibodies (1 mg/ml, undiluted) were incubated with ADV-G at 37°C for 1 h. The mixture was added to K562 cells. After culture for 72 h at 31.8°C, 5 × 10⁴ cells were cytocentrifuged onto slides, acetone fixed, and stained for ADV antigens. The number of positive cells was counted and compared to control cultures receiving ADV mixed with medium alone.