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Immunoglobulin synthesis in the human myeloma cell line U‐266; expression of two immunoglobulin heavy chain isotypes (ϵ and α) after long‐term cultivation in vitro
Author(s) -
Hellman Lars,
Josephson Staffan,
Jernberg Helena,
Nilsson Kenneth,
Pettersson Uif
Publication year - 1988
Publication title -
european journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.272
H-Index - 201
eISSN - 1521-4141
pISSN - 0014-2980
DOI - 10.1002/eji.1830180611
Subject(s) - biology , isotype , microbiology and biotechnology , immunoglobulin heavy chain , northern blot , immunoglobulin e , southern blot , locus (genetics) , antibody , messenger rna , cell culture , immunoglobulin class switching , blot , b cell , gene , monoclonal antibody , immunology , genetics
Abstract A human IgE‐producing myeloma has been cultivated in vitro as a continuous cell line (U‐266) since 1968. Analysis of immunoglobulin production during early passages of the cell line demonstrated a high synthesis rate of monoclonal IgE. Analysis of late passages, cultivated after 1980, revealed a 3‐6‐fold lower rate of IgE secretion, This decrease was accompanied by the appearance of small amounts of IgA in the culture medium together with IgE. RNA was extracted from a late passage of U‐266 and analyzed by Northern blotting, using ϵ and α‐specific oligonucleotides as hybridization probes. The results showed the presence of ϵ as well as α‐specific mRNA. Moreover the results demonstrated that the latter mRNA was derived from the α2 locus and that the ϵ and the α2‐specific mRNA contained the same V region sequences. Southern blot analysis of DNA from the late passage of the U‐266 cell line failed to reveal a recombinatory switch from the ϵ locus to the α2 locus. The expression of α2 is thus likely to be caused by differential splicing rather than by an isotype switch at the DNA level.