The murine B cell tumor, BCL1, bears monomeric IgM(λ) on its surface. After stimulation in vitro with LPS, the cells secrete pentameric IgM(λ). Comparison of μ-chains from radiolabeled intracellular, surface, and secreted IgM indicates that μ-chains from the three sites have different apparent m.w. Since the observed differences are analogous to those reported for normal murine lymphoid cells, the BCL1 cells were used for determining the structural basis for the differences in m.w. of μ-chains from the above sites. Comparative peptide analysis was performed on μ-chains from cell associated and secreted IgM. Approximately 25 peptides were identified after digestion with chymotrypsin and trypsin and analysis of peptides by cation exchange chromatography. All peptides co-eluted with the exception of a single extra peptide derived from the Fc portion of the secreted IgM. The same peptide was observed in a similar analysis using μ-chains from IgM secreted by normal splenocytes.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Immunology|
|State||Published - Jan 1 1980|
ASJC Scopus subject areas
- Immunology and Allergy