The spontaneous anti-RBC antibody response in AE^−/− NZB mice targets antigens other than Band 3. (A) SDS-PAGE analysis of wild-type murine RBC membrane preparations stained for protein with Coomassie Blue (lane i), or for glycoprotein with PAS (lane ii). Each track was loaded with approximately 20 μg protein. Major protein and glycophorin bands of the RBC membranes are labeled³²  and the apparent molecular masses are indicated in kDa. (B) Immunoprecipitation of biotin-labeled antigens from healthy murine RBCs. Immunoprecipitates were analyzed by SDS-PAGE, blotted onto nitrocellulose, and developed by luminography. Biotin-labeled RBCs were incubated with samples as follows: (i) positive control autoantibody-containing RBC eluate from wild-type NZB mice; (ii) negative control RBC eluate from healthy mice; (iii,iv) sera from individual AE^−/− NZB mice; (v,vi) RBC eluates from individual AE^−/− NZB mice; (vii,viii) control sera from individual AE^−/− NZB mice immunized with Band 3. The apparent molecular mass of the specific bands precipitated is indicated in kDa. Lanes i, ii, iii, vi, vii, and viii are from different blots.