Expression of IL-2 chimeric envelopes. (A) Immunoblots of lysates of TELCeB6 cells expressing wild-type amphotropic envelopes (A), IL2-SU, and IL2-SUX chimeras. (B) Immunoblots of viral pellets obtained by ultracentrifugation of supernatants of TELCeB6 cells expressing wild-type amphotropic envelopes (A), IL2-SU, and IL2-SUX or coexpressing wild-type amphotropic envelopes and either IL2-SU (IL2-SU/A) or IL2-SUX (IL2-SUX/A) chimeras. All blots were stained with an MLV-SU antiserum. The immunoblot of viral pellets was separated at the position of 46-kD marker, and the lower portion of the membrane was stained with a p30-CA antiserum. The positions of the IL-2 chimeric envelope glycoproteins and the wild-type amphotropic SU are indicated.