FIG 2.
The slower of the U21 bands associates with purified HLA-A and -B molecules. (a) Purified U21 (lanes 1 and 4), HLA-A2 (lane 2), HLA-B7 (lane 5), or a mixture of these molecules, as noted (lanes 3 and 6), were separated on native gels and silver stained. U21 and HLA molecules are noted. Shifted U21 and class I MHC molecules are denoted by the Δ symbols, and higher-order-shifted U21 and HLA molecules are denoted with asterisks. (b) Equal volumes of serum-free 293T culture medium containing secreted U21NSBPHA or untagged U21N were incubated alone (lanes 1 and 3) or with purified HLA-A2 (lanes 2 and 4) for 30 min at 4°C, subjected to native-PAGE, and immunoblotted with anti-U21N. Migration positions of U21N and U21NSBPHA are noted. The migration positions of shifted U21N and U21NSBPHA in the presence of HLA-A2 are denoted with white asterisks.