During immune responses, B lymphocytes may switch from the expression of immunoglobulin M (IgM) to the expression of another isotype (e.g., IgG, IgE, IgA). In stable hybridomas and myelomas expressing a "switched" (S) isotype, DNA deletions between S mu and a "downstream" S region (S region recombination) have been found. In primary B cells, studies of the molecular basis of switching have been limited by the ability to sensitively quantitate the amount of DNA deletion; such studies would be of interest because other nondeletional mechanisms (trans-splicing, alternative processing of a long transcript) have been proposed to account for isotype switching in certain circumstances. We have applied the digestion-circularization polymerase chain reaction (DC-PCR) technique to measure the amount of S region recombination that occurs in the course of class switching in primary B lymphocytes. Resting B cells were cultured in lipopolysaccharide (LPS) and interleukin 4 (IL-4) to stimulate switching to IgG1. These cells begin to express membrane IgG1 at day 2.5 of culture and reach maximum expression by day 4.5. DNA was prepared from cultured cells and analyzed for S mu-S gamma 1 rearrangement by DC-PCR. Chimeric switch regions, indicating S mu-S gamma 1 recombination, were detected in amounts that, in most cases, correlated with surface expression. Furthermore, when cells were sorted on the basis of surface IgG1 expression, a mean of at least one S mu-S gamma 1 rearrangement per cell was seen in five out of seven experiments. In general, the IgG1+ cells obtained at 4.5 and 5.5 d of culture had close to 2 S mu-S gamma 1 rearrangements per cell. In IgG1- cells, S mu-S gamma 1 rearrangements were detectable, but at frequencies substantially lower that in IgG1+ cells. Thus, these results indicate that DNA deletion accompanies class switching in normal B cells stimulated with LPS and IL-4.
Skip Nav Destination
Article navigation
1 October 1993
Article|
October 01 1993
DNA rearrangement can account for in vitro switching to IgG1.
C C Chu,
C C Chu
Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892.
Search for other works by this author on:
E E Max,
E E Max
Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892.
Search for other works by this author on:
W E Paul
W E Paul
Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892.
Search for other works by this author on:
C C Chu
Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892.
E E Max
Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892.
W E Paul
Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892.
Online ISSN: 1540-9538
Print ISSN: 0022-1007
J Exp Med (1993) 178 (4): 1381–1390.
Citation
C C Chu, E E Max, W E Paul; DNA rearrangement can account for in vitro switching to IgG1.. J Exp Med 1 October 1993; 178 (4): 1381–1390. doi: https://doi.org/10.1084/jem.178.4.1381
Download citation file:
Sign in
Don't already have an account? Register
Client Account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.
Sign in via your Institution
Sign in via your InstitutionSuggested Content
Email alerts
Advertisement