Immunoglobulin switch circular DNA in the mouse infected with Nippostrongylus brasiliensis: Evidence for successive class switching from μ to ε via γ1

K. Yoshida, M. Matsuoka, S. Usuda, A. Mori, K. Ishizaka, H. Sakano

Research output: Contribution to journalArticle


We have characterized immunoglobulin switch circular DNA in mice infected with the nematode parasite Nippostrongylus brasiliensis. Two kinds of circular DNA were identified in the lymph nodes as excision products of switch recombination of immunoglobulin heavy-chain constant region (C(H)) genes. One is a recombinant between C(μ) and C(γ1) (γ1 circle), and the other is a recombinant between C(γ1) and C(ε) (ε circle). In the ε circle, a short piece of switch μ (S(μ)) sequence was inserted between S(ε) and S(γ1) sequences. The inserted S(μ) sequence could be a trace of the preceding switch from C(μ) to C(γ1). These findings indicate that parasitic infection can induce class switch recombinations in a successive manner, first from C(μ) to C(γ1), and then from C(γ1) to C(ε).

Original languageEnglish (US)
Pages (from-to)7829-7833
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number20
StatePublished - Jan 1 1990



  • IgE
  • IgG1
  • interleukin 4
  • parasite infection
  • switch recombination

ASJC Scopus subject areas

  • General

Cite this