Partial expression of the lpr locus in the heterozygous state: presence of autoantibodies.
B6 mice heterozygous at the lpr locus (B6 +/lpr and B6 lpr/+) were compared with lpr homozygous mice (B6 lpr/lpr) and control mice (B6 +/+) for levels of serum immunoglobulin (Ig), presence of autoantibodies and rate of B-cell membrane immunoglobulin (mIg) capping. The total serum Ig levels in B6 +/lpr and B6 lpr/+ mice remained much below the high titres found in B6 lpr/lpr mice, and were close to the titres found in B6 +/+ mice. However, the presence of anti-single-stranded (ss) DNA antibodies and of anti-nuclear antibodies (ANA) was detected in most B6 +/lpr and B6 lpr/+ mice, although less frequently and in lower titres than in B6 lpr/lpr mice. The rate of mIg capping was higher in B6 +/lpr and B6 lpr/+ mice than in B6 +/+ mice, but the acceleration of the capping process remained inferior to the one found in B6 lpr/lpr mice. Therefore, the lpr locus is not totally recessive: some B-cell hyperactivity is expressed in the heterozygous state. This is in contrast with its lack of expression at the level of lympho-proliferation of the lpr-characteristic T-cell subset: none of the lpr heterozygous B6 mice displayed detectable lymphadenopathy.
Jachez
B
B
Laboratoire d'Immunologie, Université Louis Pasteur, Strasbourg, France.
Montecino-Rodriguez
E
E
Fonteneau
P
P
Loor
F
F
D000375:Aging; D000818:Animals; D000974:Antibodies, Antinuclear / Q000032:analysis; D001323:Autoantibodies / Q000032:analysis*; D001327:Autoimmune Diseases / Q000235:genetics; D001402:B-Lymphocytes / Q000276:immunology; D002874:Chromosome Mapping; D004277:DNA, Single-Stranded / Q000032:analysis; D005260:Female; D006579:Heterozygote; D007136:Immunoglobulins / Q000032:analysis; D007152:Immunologic Capping; D008232:Lymphoproliferative Disorders / Q000235:genetics; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains
D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D004277:DNA, Single-Stranded; D007136:Immunoglobulins