Several genes contribute to the production of autoreactive B and T cells in the murine lupus susceptibility locus Sle1c.
The systemic lupus erythematosus 1 (Sle1) locus mediates the loss of tolerance to nuclear Ags in the NZM2410 mouse model of lupus through intrinsic defects in both B and T cells. Congenic analysis has shown that Sle1 corresponds to at least three genetic loci, Sle1a, Sle1b, and Sle1c. Telomeric Sle1c is associated with abnormal B cell responses to subthreshold stimulation with anti-IgM and C3d and with decreased T-dependent humoral immune responses. We have proposed that these phenotypes resulted from polymorphisms in the C3 complement receptor Cr2 gene. We have also found that Sle1c was associated with the production of histone-specific autoreactive CD4(+) T cells, which correlated with higher activation and proliferative responses, and a reduction in the CD4(+)CD25(+)CD62L(+)forkhead/winged helix transcription factor gene (Foxp3(+)) compartment. In this study we showed, using congenic recombinants, that the decreased humoral immune response and impaired GC formation map to the NZM2410 Cr2 allele. A chronic graft-vs-host disease model also showed that Sle1c produces significantly more autoreactive B cells than B6 controls, and that this phenotype maps to two regions excluding the Cr2 gene. Mixed bone marrow chimera demonstrated that the increased activation, proliferative response, and reduced regulatory T cell compartment were intrinsic to Sle1c-expressing CD4(+) T cells. These phenotypes mapped to the same two loci identified with the chronic graft-vs-host disease model, excluding the Cr2 region. Overall, these results show that Sle1c results in the production of autoreactive B and T cells through the expression of three different genes, one of which is consistent with Cr2, based on the phenotypes of the Cr2-deficient mice, and the other two corresponding to as yet unidentified genes.
Department of Pathology, Immunology, and Laboratory Medicine, Department of Medicine, University of Florida, Gainesville, FL 32610, USA.
Yifang
Y
Chen
Daniel
D
Perry
Susan A
SA
Boackle
Eric S
ES
Sobel
Hector
H
Molina
Byron P
BP
Croker
Laurence
L
Morel
D000818:Animals; D016175:B-Lymphocyte Subsets / Q000276:immunology* / Q000473:pathology / Q000528:radiation effects; D002454:Cell Differentiation / Q000235:genetics* / Q000276:immunology*; D002874:Chromosome Mapping; D005260:Female; D005819:Genetic Markers / Q000276:immunology; D020022:Genetic Predisposition to Disease; D018858:Germinal Center / Q000276:immunology / Q000473:pathology; D006086:Graft vs Host Disease / Q000235:genetics / Q000276:immunology; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D016130:Immunophenotyping; D008180:Lupus Erythematosus, Systemic / Q000235:genetics* / Q000276:immunology* / Q000473:pathology; D008297:Male; D051379:Mice; D020297:Mice, Congenic; D008810:Mice, Inbred C57BL; D008814:Mice, Inbred NZB; D011828:Radiation Chimera; D017464:Receptors, Complement 3d / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics; D011995:Recombination, Genetic / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000473:pathology / Q000528:radiation effects
D005819:Genetic Markers; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D017464:Receptors, Complement 3d