Membrane-bound and secreted IgA contain structurally different α-chains

R. Sitia, H. Kikutani, A. Rubartelli, Y. Bushkin, J. Stavnezer, U. Hammerling

Research output: Contribution to journalArticlepeer-review


Three different forms of α-chains are synthesized by BF0.3 and 615.2, two cloned cell lines derived from the murine B lymphoma I.29. The three forms of α-chains differ in size, pI, cellular location, and rate of turnover. They were identified by means of lactoperoxidase-catalyzed radioiodination, internal 14C or 35S labeling, and immunofluorescence techniques as membrane-bound (α(m)), secreted (α(s)), and intracellular (α(ic)) proteins. Comparison of immunoglobulin products of the two lymphoma lines with those of a hybridoma cell line, Id 150, which secretes IgA of the I.29 idiotype but lacks membrane IgA, confirmed the assignments of α(m), α(s), and α(ic). Results of biosynthetic labeling of BF0.3, 615.2, and Id 150 in the presence and absence of tunicamycin suggest that the difference in m.w. and charge observed between α(m) and α(s) can be attributed to differences in primary amino acid structure rather than different degreees of glycosylation.

Original languageEnglish
Pages (from-to)712-716
Number of pages5
JournalJournal of Immunology
Issue number2
Publication statusPublished - 1982

ASJC Scopus subject areas

  • Immunology


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