Ig Mu-Epsilon Isotype Switch in Il-4-Treated Human B-Lymphoblastoid Cells - Evidence for a Sequential Switch (Journal article)

Mills, F. C./ Thyphronitis, G./ Finkelman, F. D./ Max, E. E.

IgE is produced by B lymphocytes that have undergone a deletional rearrangement of their Ig H chain gene locus, a rearrangement that joins the switch region of the mu-gene, S-mu, with the corresponding region of the epsilon-gene, S-epsilon. To examine the resulting composite S-mu-S-epsilon junctions of human lymphoid cells, we have used a polymerase chain reaction strategy to clone the switch regions of the human myeloma U266 and of two IgE-producing human cell lines generated by treatment of lymphocytes with EBV plus IL-4. The switch junction of one of the EBV lines is a complex rearrangement in which a fragment of S-gamma is interposed between S-mu and S-epsilon. This finding suggested that the switch to epsilon in this human lymphoid cell was preceded by a S-mu-S-gamma recombination. To determine whether this sequential switch rearrangement represented a unique event or occurred with some regularity in human B cells switching to IgE production, DNA samples from bulk cultures of lymphocytes treated with IL-4 were subjected to polymerase chain reaction amplification of their S-mu-S-epsilon junctions. When the resulting fragments were examined by Southern blotting, a substantial fraction hybridized to an S-gamma probe. This finding suggests that sequential recombination involving S-gamma is not rare in the switch to epsilon-production in humans. Our polymerase chain reaction strategy should be useful in studying isotype switching at the DNA level.
Institution and School/Department of submitter: Πανεπιστήμιο Ιωαννίνων. Σχολή Επιστημών και Τεχνολογιών. Τμήμα Βιολογικών Εφαρμογών και Τεχνολογιών
Keywords: epstein-barr virus,human lymphocytes-b,heavy-chain switch,interferon-gamma,c-epsilon,gene,recombination,mechanism,expression,region
URI: https://olympias.lib.uoi.gr/jspui/handle/123456789/7850
ISSN: 0022-1767
Link: <Go to ISI>://A1992JF47400045
Appears in Collections:Άρθρα σε επιστημονικά περιοδικά ( Ανοικτά)

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