Self-reactive repertoire of tight skin (TSK/+) mouse: immunochemical and molecular characterization of anti-cellular autoantibodies.

The tight skin (TSK/+) mouse has been proposed as an experimental model for progressive systemic sclerosis because of the biochemical alterations in collagen synthesis and pathological similarities to the human disease. Here, we report the analysis of tight skin mice sera for the presence of anti-cytoplasmic and anti-nuclear autoantibodies and determination of the frequency of hybridomas producing anti-cellular autoantibodies. The binding specificity of TSK mAbs to nuclear and cytoplasmic antigens such as keratin, actin, vimentin, and mitochondria was determined.

High-specificity in-situ hybridization. Methods and application.

We describe a technique of in-situ hybridization using oligonucleotide probes employing the expression of immunoglobulin VH genes as a model. Optimal conditions for hybridization with the 35S-labeled oligonucleotide probes were established with monoclonal B-cell lines that express VH genes of known nucleic acid sequence. The range of sensitivity and specificity achieved with this technique is documented.

Independent analysis of the 16/6 idiotype lupus model. A role for an environmental factor?

The recent description of a lupus-like disease in normal mice after injections of human mAb that bind DNA and carry the common Id 16/6 Id has excited much attention. In an effort to reproduce this model we have performed two experiments using eight human mAb three of which bear the 16/6 Id. Despite using an injection protocol very similar to that of the original authors and waiting for up to 1 yr we were unable to detect any autoantibodies or any evidence of renal disease.

Molecular analysis of a germ line-encoded idiotypic marker of pathogenic human lupus autoantibodies.

Id-16/6 is an idiotypic marker found in both IgM and IgG antibodies, as well as in the tissue lesions of patients with SLE. The prototypic Id-16/6+ mAb is 18/2, whose VH3-derived H chain is encoded by an unmutated germ-line gene. We found that the H chains of VH3-derived Id-16/6+ antibodies contain the major determinants of Id-16/6.

An immunoglobulin light chain from a lupus-prone mouse induces autoantibodies in normal mice.

Autoantibodies against the 70-kD U1 RNP nucleoprotein autoantigen and DNA were elicited in normal BALB/c mice with a purified Ig light chain. This light chain, derived from a lupus-prone MRL-lpr/lpr mouse, has two distinctive properties: it contains an idiotypic marker recognized by a monoclonal MRL-lpr/lpr anti-snRNP autoantibody, and the amino acid sequence of its third hypervariable region (CDR3) is homologous to a sequence in an antigenic region of the 70-kD U1 RNP polypeptide. The results demonstrate that an Ig idiotype that mimics an autoantigen can induce autoimmunization.