Binding and interference properties of cloned AKR6 SU and 1E SU. (A) LAPSN(AKR6env) and LAPSN(10A1env) vector titers were measured on dunni cells and dunni cells infected with replication-competent AKR6 or 1E viruses. Data shown are means ± SD of at least two independent experiments with duplicate determinations in each experiment. (B) Binding of 1E-SU-IgG to dunni cells and to dunni cells infected with replication-competent viruses. (C) Binding of Ampho-SU-IgG to dunni cells infected with 4070A amphotropic virus. Data in (B) and (C) are from a representative experiment and show data from ~18,000 live cells (cells that exclude propidium iodide) per histogram.