Immunization of nonautoimmune mice with DNA binding domains of the largest subunit of RNA polymerase I results in production of anti-dsDNA and anti-Sm/RNP antibodies.

Antibodies against the N-terminal (NT) but not the basic domain (BD), DNA binding regions of the largest subunit (S1) of RNA polymerase I (RNAPI) were detected in the sera of MRL-lpr/lpr lupus mice. Antibodies against both RNAPI(S1)-NT and -BD, as well as other systemic lupus erythematosus (SLE) autoantigens (La, ribosomal P proteins and Sm/RNP) were produced by rabbits immunized with anti-DNA antibodies that had been affinity purified from SLE patients. Immunization of nonautoimmune mice (Balb/c) with RNAPI(S1)-NT, RNAPI(S1)-BD, or La in the form of GST fusion proteins, induced production of anti-double-stranded (ds) DNA and anti-Sm/RNP. GST-P1 did not induce an anti-dsDNA response in these mice. These results demonstrate that RNAPI(S1)-NT, RNAPI(S1)-BD and La can participate in an anti-autoantigen/anti-DNA antibody loop during an SLE-like autoimmune response.

Gene therapy for pituitary tumors.

Pituitary tumors are the most common primary intracranial neoplasms. Although most pituitary tumors are considered typically benign, others can cause severe and progressive disease. The principal aims of pituitary tumor treatment are the elimination or reduction of the tumor mass, normalization of hormone secretion and preservation of remaining pituitary function. In spite of major advances in the therapy of pituitary tumors, for some of the most difficult tumors, current therapies that include medical, surgical and radiotherapeutic methods are often unsatisfactory and there is a need to develop new treatment strategies. Gene therapy, which uses nucleic acids as drugs, has emerged as an attractive therapeutic option for the treatment of pituitary tumors that do not respond to classical treatment strategies if the patients become intolerant to the therapy. The development of animal models for pituitary tumors and hormone hypersecretion has proven to be critical for the implementation of novel treatment strategies and gene therapy approaches. Preclinical trials using several gene therapy approaches for the treatment of anterior pituitary diseases have been successfully implemented. Several issues need to be addressed before clinical implementation becomes a reality, including the development of more effective and safer viral vectors, uncovering novel therapeutic targets and development of targeted expression of therapeutic transgenes. With the development of efficient gene delivery vectors allowing long-term transgene expression with minimal toxicity, gene therapy will become one of the most promising approaches for treating pituitary adenomas.

Autoantibodies and autoantigens in the urine of SLE patients.

Autoantibodies against RNA polymerase I (RNAPI), DNA, La and ribosomal P proteins were detected in the urine of systemic lupus erythematosus (SLE) patients, many with normal protein excretion rates. In a number of cases, the antibodies were detectable in the urine but not the serum sample of the same patient. The presence and relative concentrations of the urinary autoantibodies correlated with disease activity. RNAPI antigens were detected in the urine of SLE patients by radioimmunoassay and immunoblotting using rabbit antisera prepared against the purified holoenzyme. Immunoaffinity purification of the rabbit anti-RNAPI with SLE urine proteins resulted in antibodies directed primarily against the largest RNAPI subunit (S1; 194 kDa). Antibodies prepared against recombinant fusion proteins representing the DNA binding regions of human RNAPI(S1) reacted with a 35 kDa SLE urinary protein, a putative fragment of RNAPI(S1). Ribosomal protein P0 was detected in SLE patients' urine by immunoblotting, using rabbit antiserum prepared against recombinant human P1 fusion protein. The relative quantities of urinary P0 correlated with disease status. Analysis of urinary autoantibodies and corresponding antigens in conjunction with analysis of serum autoantibodies may be of value for the purpose of monitoring disease activity.

Regulatable gutless adenovirus vectors sustain inducible transgene expression in the brain in the presence of an immune response against adenoviruses.

In view of recent serious adverse events and advances in gene therapy technologies, the use of regulatable expression systems is becoming recognized as indispensable adjuncts to successful clinical gene therapy. In the present work we optimized high-capacity adenoviral (HC-Ad) vectors encoding the novel tetracycline-dependent (TetOn)-regulatory elements for efficient and regulatable gene expression in the rat brain in vivo. We constructed two HC-Ad vectors encoding beta-galactosidase (beta-gal) driven by a TetOn system containing the rtTAS(s)M2 transactivator and the tTS(Kid) repressor under the control of the murine cytomegalovirus (mCMV) (HC-Ad-mTetON-beta-Gal) or the human CMV (hCMV) promoter (HC-Ad-hTetON-beta-Gal). Expression was tightly regulatable by doxycycline (Dox), reaching maximum expression in vivo at 6 days and returning to basal levels at 10 days following the addition or removal of Dox, respectively. Both vectors achieved higher transgene expression levels compared to the expression from vectors encoding the constitutive mCMV or hCMV promoter. HC-Ad-mTetON-beta-Gal yielded the highest transgene expression levels and expressed in both neurons and astrocytes. Antivector immune responses continue to limit the clinical use of vectors. We thus tested the inducibility and longevity of HC-Ad-mediated transgene expression in the brain of rats immunized against adenovirus by prior intradermal injections of RAds. Regulated transgene expression from HC-Ad-mTetON-beta-Gal remained active even in the presence of a significant systemic immune response. Therefore, these vectors display two coveted characteristics of clinically useful vectors, namely their regulation and effectiveness even in the presence of prior immunization against adenovirus.