Figure 3.

Analysis, by SDS–PAGE under non-reducing conditions, of ³⁵S-labelled DNP-binding antibody produced by transfected and untransfected cell lines. X-10 is the parental cell line producing κ-chains only, and Sp6 is the parental cell line producing both κ- and wild-type mouse μ-chains. Other lanes show the analysis of mutant mouse antibody, produced by transfection of X-10 cells with a mouse μ gene in which the C-terminal sequence has been altered. The name of the species from which the introduced μ-chain C-terminal sequence was taken (Table 2) is indicated above each lanes. The presence of Cys or Ser at position 414 of the μ-chain is also indicated above each lane. The mobility of the IgM standards [mouse IgM (TEPC 183 and Sp6) and catfish IgM] with eight, 10, or 12 ‘halfmer’ (μL) units is indicated by arrows.