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Anti-DNA B cells in MRL/lpr mice show altered differentiation and editing pattern.

Li Y, Li H, Ni D, Weigert M - J. Exp. Med. (2002)

Bottom Line: This transgene codes for a heavy chain that forms anti-double-stranded DNA (dsDNA) antibody when paired with most members of the endogenous Vkappa repertoire, but certain L chains, referred to as Vkappa editors, do not sustain dsDNA binding in combination with 3H9H/56R.In the nonautoimmune 3H9H/56R BALB/c, most B cells generated do not bind DNA because the transgene itself is edited or is associated with a Vkappa editor.Anti-dsDNA B cells use noneditor kappas but, in addition, most anti-dsDNA B cells have edited the heavy chain transgene. lambda1 B cells (without the coexpression of a kappa editor) are found and the kappa/lambda1 MZ population is absent.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.

ABSTRACT
We have studied the regulation of anti-DNA B cells in transgenic mice with a heavy chain transgene (3H9H/56R). This transgene codes for a heavy chain that forms anti-double-stranded DNA (dsDNA) antibody when paired with most members of the endogenous Vkappa repertoire, but certain L chains, referred to as Vkappa editors, do not sustain dsDNA binding in combination with 3H9H/56R. In the nonautoimmune 3H9H/56R BALB/c, most B cells generated do not bind DNA because the transgene itself is edited or is associated with a Vkappa editor. A minor population of B cells (30%) bind dsDNA and express the lambda1 light chain (known to sustain 3H9H/56R DNA binding). These 3H9/56R/lambda1 B cells coexpress a kappa editor, and we propose that the down-regulation of the anti-DNA BCR caused by the dual L chain expression may prevent activation of this kappa/lambda population. These kappa/lambda B cells are sequestered in the marginal zone. Here, we studied the influence of autoimmunity on expression and regulation of 3H9H/56R. In 3H9H/56R MRL/lpr mice, the expression of anti-dsDNA is vastly accelerated. Anti-dsDNA B cells use noneditor kappas but, in addition, most anti-dsDNA B cells have edited the heavy chain transgene. lambda1 B cells (without the coexpression of a kappa editor) are found and the kappa/lambda1 MZ population is absent. Our results suggest that improper editing and failure to sequester autoreactive B cells may contribute to the breakdown of tolerance in MRL/lpr mice.

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Anti-dsDNA in the sera of BALB/c and MRL/lpr. 3H9H/56R BALB/c, 3H9H/56R MRL/lpr, and their nontransgenic littermates were bled at 6, 8, and 12 wk. (Numbers of animals tested: BALB/c 6w, n = 5; 3H9H/56R BALB/c 6w, n = 4; MRL/lpr 6w, n = 4; 3H9H/56R MRL/lpr 6w, n = 8; BALB/c 8w, n = 5; 3H9H/56R BALB/c 8w, n = 4; MRL/lpr 8w, n = 3; 3H9H/56R MRL/lpr 8w, n = 9; BALB/c 12w, n = 7; 3H9H/56R BALB/c 12w, n = 7; MRL/lpr 12w, n = 4; 3H9H/56R MRL/lpr 12w, n = 5.) Serum samples were tested for anti-dsDNA IgM and IgG by ELISA at 1:100 dilution.
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fig1: Anti-dsDNA in the sera of BALB/c and MRL/lpr. 3H9H/56R BALB/c, 3H9H/56R MRL/lpr, and their nontransgenic littermates were bled at 6, 8, and 12 wk. (Numbers of animals tested: BALB/c 6w, n = 5; 3H9H/56R BALB/c 6w, n = 4; MRL/lpr 6w, n = 4; 3H9H/56R MRL/lpr 6w, n = 8; BALB/c 8w, n = 5; 3H9H/56R BALB/c 8w, n = 4; MRL/lpr 8w, n = 3; 3H9H/56R MRL/lpr 8w, n = 9; BALB/c 12w, n = 7; 3H9H/56R BALB/c 12w, n = 7; MRL/lpr 12w, n = 4; 3H9H/56R MRL/lpr 12w, n = 5.) Serum samples were tested for anti-dsDNA IgM and IgG by ELISA at 1:100 dilution.

Mentions: Anti–DNA B cells are differentially regulated in healthy mice. In the conventional anti-DNA transgenics on a BALB/c genetic background, no anti-DNA is expressed (4). Significant levels of IgM anti-DNA are seen in the site-directed transgene (sd-tg) 3H9H/56R BALB/c at the age of 6–8 wk (Fig. 1) . There seems to be a gradual loss of anti-DNA IgM, although some mice tested at 12 wk still have significant titer. We do not understand this difference. However, no IgG anti-DNA is expressed. Thus, the IgG anti-dsDNA characteristic of Lupus is tightly regulated in BALB/c mice.


Anti-DNA B cells in MRL/lpr mice show altered differentiation and editing pattern.

Li Y, Li H, Ni D, Weigert M - J. Exp. Med. (2002)

Anti-dsDNA in the sera of BALB/c and MRL/lpr. 3H9H/56R BALB/c, 3H9H/56R MRL/lpr, and their nontransgenic littermates were bled at 6, 8, and 12 wk. (Numbers of animals tested: BALB/c 6w, n = 5; 3H9H/56R BALB/c 6w, n = 4; MRL/lpr 6w, n = 4; 3H9H/56R MRL/lpr 6w, n = 8; BALB/c 8w, n = 5; 3H9H/56R BALB/c 8w, n = 4; MRL/lpr 8w, n = 3; 3H9H/56R MRL/lpr 8w, n = 9; BALB/c 12w, n = 7; 3H9H/56R BALB/c 12w, n = 7; MRL/lpr 12w, n = 4; 3H9H/56R MRL/lpr 12w, n = 5.) Serum samples were tested for anti-dsDNA IgM and IgG by ELISA at 1:100 dilution.
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2196070&req=5

fig1: Anti-dsDNA in the sera of BALB/c and MRL/lpr. 3H9H/56R BALB/c, 3H9H/56R MRL/lpr, and their nontransgenic littermates were bled at 6, 8, and 12 wk. (Numbers of animals tested: BALB/c 6w, n = 5; 3H9H/56R BALB/c 6w, n = 4; MRL/lpr 6w, n = 4; 3H9H/56R MRL/lpr 6w, n = 8; BALB/c 8w, n = 5; 3H9H/56R BALB/c 8w, n = 4; MRL/lpr 8w, n = 3; 3H9H/56R MRL/lpr 8w, n = 9; BALB/c 12w, n = 7; 3H9H/56R BALB/c 12w, n = 7; MRL/lpr 12w, n = 4; 3H9H/56R MRL/lpr 12w, n = 5.) Serum samples were tested for anti-dsDNA IgM and IgG by ELISA at 1:100 dilution.
Mentions: Anti–DNA B cells are differentially regulated in healthy mice. In the conventional anti-DNA transgenics on a BALB/c genetic background, no anti-DNA is expressed (4). Significant levels of IgM anti-DNA are seen in the site-directed transgene (sd-tg) 3H9H/56R BALB/c at the age of 6–8 wk (Fig. 1) . There seems to be a gradual loss of anti-DNA IgM, although some mice tested at 12 wk still have significant titer. We do not understand this difference. However, no IgG anti-DNA is expressed. Thus, the IgG anti-dsDNA characteristic of Lupus is tightly regulated in BALB/c mice.

Bottom Line: This transgene codes for a heavy chain that forms anti-double-stranded DNA (dsDNA) antibody when paired with most members of the endogenous Vkappa repertoire, but certain L chains, referred to as Vkappa editors, do not sustain dsDNA binding in combination with 3H9H/56R.In the nonautoimmune 3H9H/56R BALB/c, most B cells generated do not bind DNA because the transgene itself is edited or is associated with a Vkappa editor.Anti-dsDNA B cells use noneditor kappas but, in addition, most anti-dsDNA B cells have edited the heavy chain transgene. lambda1 B cells (without the coexpression of a kappa editor) are found and the kappa/lambda1 MZ population is absent.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.

ABSTRACT
We have studied the regulation of anti-DNA B cells in transgenic mice with a heavy chain transgene (3H9H/56R). This transgene codes for a heavy chain that forms anti-double-stranded DNA (dsDNA) antibody when paired with most members of the endogenous Vkappa repertoire, but certain L chains, referred to as Vkappa editors, do not sustain dsDNA binding in combination with 3H9H/56R. In the nonautoimmune 3H9H/56R BALB/c, most B cells generated do not bind DNA because the transgene itself is edited or is associated with a Vkappa editor. A minor population of B cells (30%) bind dsDNA and express the lambda1 light chain (known to sustain 3H9H/56R DNA binding). These 3H9/56R/lambda1 B cells coexpress a kappa editor, and we propose that the down-regulation of the anti-DNA BCR caused by the dual L chain expression may prevent activation of this kappa/lambda population. These kappa/lambda B cells are sequestered in the marginal zone. Here, we studied the influence of autoimmunity on expression and regulation of 3H9H/56R. In 3H9H/56R MRL/lpr mice, the expression of anti-dsDNA is vastly accelerated. Anti-dsDNA B cells use noneditor kappas but, in addition, most anti-dsDNA B cells have edited the heavy chain transgene. lambda1 B cells (without the coexpression of a kappa editor) are found and the kappa/lambda1 MZ population is absent. Our results suggest that improper editing and failure to sequester autoreactive B cells may contribute to the breakdown of tolerance in MRL/lpr mice.

Show MeSH
Related in: MedlinePlus