Human immunoglobulin transgenes undergo rearrangement, somatic mutation and class switching in mice that lack endogenous IgM

Abstract

We have generated transgenic mice that contain human-sequence Ig miniloci and, because they are also homozygous for a targeted disruption of their endogenous heavy chain genes, must rely on the transgene sequences for B cell receptor expression. Although the human transgenes contain only a fraction of the intact human heavy chain locus, these defined sequences are able to at least partially restore the humoral immune system in the mouse. B cells expressing human heavy chains develop in the bone marrow, populate peripheral lymphoid tissue and respond specifically to antigen. Furthermore, the heavy chain transgenes contain both human mu and gamma 1 coding exons as well as the respective mu and gamma 1 switch regions. The sequences included within the transgene are sufficient to direct class switch recombination. Transgene sequences are also sufficient to direct somatic mutation of the class-switched heavy chain genes. These observations define the upper limit of the cis-acting sequences necessary to direct heavy chain class switching and somatic mutation.

Antibody Expression from the Core Region of the Human IgH Locus Reconstructed in Transgenic Mice Using Bacteriophage P1 Clones

“…the production of human monoclonal antibodies (Brü gHere, we have examined the possibility of using gemann et al, 1989, 1991; Brü ggemann and Neu-bacteriophage P1 clones to reconstitute a core human berger, 1991; Davies et al, 1993;Green et al, 1994; IgH locus in transgenic mice. Phage P1 clones contain Lonberg et al, 1994;Taylor et al, 1992Taylor et al, , 1993; Wagner about 100 kb of inserted DNA and are propagated in The EcoRI restriction map is taken from Shin et al (1991). The end probes derived from the NotI and SalI sides of P128 are shown as gray bars.…”

Sensitive analysis of recombination activity using integrated cell surface reporter substrates

“…The basic structure of S-sequences and the mechanism of their activation are highly conserved, so that human S-sequences are recombined in transgenic mice (33). The selected promoters function in most cell types, and the termination signal has so far been shown to work in murine and human cells (13).…”

Use of D gene segments with irregular spacers in terminal deoxynucleotidyltransferase (TdT)+/+and TdT−/−mice carrying a human Ig heavy chain transgenic minilocus

“…pHC1, the construct used to establish the transgenic founder line 119, is 60 kb long and has been described (16)(17)(18)(19)(20). TdT Ϫ/Ϫ mice have been described (11,26).…”

“…To study the mechanisms of Ig V H DJ H recombination, we engineered mice transgenic for a human Ig heavy chain minilocus, pHC1 (15)(16)(17)(18)(19)(20)(21)(22). One of the D gene segments present in the transgenic minilocus belongs to the D gene segments with irregular spacers (DIR) family.…”