Figure 2.

Immunoprecipitation of LFA-1 subunits from JY lymphoblastoid cells. (A and C) Cells were pulsed for 1 h with [³⁵S]cysteine and chased for 16 h with unlabeled cysteine. (B and D) Cells were pulsed for 1 h with [³⁵S]cysteine. (A and B) Lysates were immunoprecipitated with X63 myeloma IgG1 as control (lane 1), mouse anti-human β subunit (lanes 2–17), and mouse anti-human α_L subunit (lane 18) mAbs. As a control, mature LFA-1 was precipitated with TS1/18 mAb from lysates of JY cells that were pulsed and chased for 16 h (B, lane 19). (C and D) A separate experiment with 11H6 mAb (lane 3), a batch of which was obtained after other work was completed. Controls with X63 myeloma IgG1 (lane 1), mAb to α_L (lane 2), and CBR LFA-1/2 mAb to β₂ (lane 4) were included. Precipitates were subjected to reducing SDS/7.5% PAGE and fluorography. The positions of mature α_L, α′_L precursor, mature β₂, and β′₂ precursor subunits are indicated. Molecular weight standards are myosin (200 kDa), β-galactosidase (116 kDa), phosphorylase b (97 kDa), and serum albumin (66 kDa).