Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Recombinant dna technique included in method of making a...
Reexamination Certificate
1991-05-24
2001-10-16
Kunz, Gary L. (Department: 1647)
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Recombinant dna technique included in method of making a...
C435S006120, C435S007100, C435S071100, C435S320100, C530S403000, C536S023500
Reexamination Certificate
active
06303339
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to peptides bearing selected antigenic epitopes and to nucleic acid compositions which may be employed in the preparation of such peptides, or to detect the presence of complementary nucleic acid sequences in biological samples. More particularly, the invention concerns peptides bearing antigenic epitopes corresponding to epitopes on the 60 kD polypeptide of the Ro/SS-A antigen (also referred to simply as the “Ro” antigen), and to DNA sequences encoding all or a portion of the 60 kD polypeptide. The invention further relates to processes incorporating the foregoing peptides and/or nucleic acid sequences, such as in the immunocharacterization of various autoimmune diseases or in the preparation of recombinant Ro antigen.
2. Description of the Related Art
Patients with rheumatic diseases can make autoantibodies to a variety of biological compounds derived from their own cells, including autoantibodies to products secreted by cells (e.g., rheumatoid factor to immuno-globulins), constituents of the plasma membrane (e.g., phospholipids, insulin receptors) as well as an array of intracellular components. Interestingly, of the greater than 10,000 macromolecules found inside a cell, only about 30 are targets of autoantibody production (1). However, autoimmune antibodies having immunospecificity for one or more of these targets are found in a wide array of rheumatic diseases, including systemic lupus erythematosus (SLE), mixed connective tissue disease (MCTD), primary sicca syndrome, polymyositis, dermatomyositis, progressive systemic sclerosis (PSS), rheumatoid arthritis (RA), idiopathic thrombocytopenic purpura (ITP), primary biliary cirrhosis (PBC), chronic active hepatitis (CAH), and a variety of others.
Accordingly, the presence of autoantibodies in the serum of a patient is generally indicative of one or another of the various foregoing conditions. For example, autoantibodies to double-stranded (ds) DNA occur in 50-70% of SLE patients and are highly specific for this disease (2). This autoantibody is also occasionally seen in clinical settings where SLE overlaps with other rheumatic diseases (e.g., mixed connective tissue disease). Moreover, circulating ds-DNA antibody levels fluctuate with systemic disease activity, particularly renal involvement (3-4), and this autoantibody specificity has been implicated in the more aggressive forms of lupus nephritis (5-6).
The presence of one or more of a variety of other autoantibodies have been used as indicators of rheumatic disease, including antibodies having specificity for chromatin structural proteins such as histones or nucleosomal structures or antibodies to ribonucleoprotein particles (RNP) such as nRNP, U1 snRNP and Sm antigens. For example, studies employing solid phase immunoassays have shown that anti-histone antibodies can be found in about 50% of the sera of unselected SLE patients (7-9), and in approximately 80% of patients with active disease (9).
The appearance of antibodies to Ro/SS-A and La/SS-B RNPs were probably first detected in 1958 in the search of patients with Sjogren's Syndrome, employing extracts of salivary tissue as antigens (10). Later studies demonstrated two major specificities in salivary tissue designated SjD and Sjt (11), probably corresponding to Ro/SS-A and La/SS-B, respectively. Reichlin and Harley have offered several recent comprehensive reviews of the clinical correlations of the Ro/SS-A and La/SS-B antigen-antibody systems (12-13).
Most interest has centered on the Ro/SS-A system since an autoantibody response to this antigen is much more common than one to La/SS-B. In addition, an autoantibody response to La/SS-B is almost invariably associated with anti-Ro/SS-A antibody production. Anti-Ro/SS-A autoantibodies occur in the highest prevalence in Sjogren's syndrome (SS) patients. Moreover, some investigators have suggested that the use of a sufficiently sensitive solid phase assay employing purified Ro/SS-A antigen, virtually all SS patients produce this autoantibody (14).
Unfortunately, although purified Ro/SS-A antigen can be employed to immunodiagnose various autoimmune disorders and particularly Sjogren's syndrome, there are significant problems associated with its use. Of principal importance is the fact that although Ro/SS-A RNP particles can be isolated to some degree of purity (15), to do so is economically impractical. This is due principally to the high cost and time of isolating Ro/SS-A antigen proteins from natural sources. Moreover, in that the Ro/SS-A antigen is an RNP particle, it generally has stricter requirements for storage, as well as a more limited ability to prepare for commercial distribution. While a recombinant version of one or more protein subcomponents would prove to be useful in this regard, their development has not been deported. Clearly there is a need for such a recombinant version, including a need for DNA segments which can be employed in the preparation of peptides containing Ro antigenic sequences, which would provide a means for producing improved antigenic materials which may be recognized by antisera having specificity for autoimmune antigens such as Ro/SS-A.
SUMMARY OF THE INVENTION
Accordingly, the invention concerns methods and compositions which may be employed to prepare an improved autoimmune antigenic material that addresses at least some of the disadvantages in the art.
The invention further concerns antigenic material that may be employed in the immunoidentification of autoimmune diseases, and particularly autoimmune diseases such as Sjogren's syndrome, lupus erythematosus and similar or related disorders.
More particularly, the Invention concerns relatively small peptides which may be substituted for RNP antigens such as Ro/SS-A in immunoassays, yet which may be readily prepared synthetically, and easily stored for extended periods of time.
The present invention addresses these concerns in certain embodiments through the provision of DNA sequences which encode antigenic epitopes, referred to herein as epitopic core sequences, of the 60 kD Ro antigen peptide, or biologically functional equivalents thereof. Most conveniently, one will desire to employ the 60 kD Ro antigen-encoding sequences of the invention to produce essentially the complete, natural 60 kD protein by recombinant means. However, for certain applications, the preparation of shorter transcriptional units encoding epitopic core sequence(s) might prove desirable. Therefore, as used herein, the phrase “60 kD antigen”, and variations thereof, is intended to refer generally to proteins and peptides bearing the antigenic sequences, including epitopic core sequences, as set forth in the present disclosure. It is specifically pointed out that the use of “60 kD” designation is intended as a reference to the natural 60 kD Ro antigen as a shorthand means or “coined” term for referring to the subject matter of the invention, and is not in any way intended to set forth or imply that the invention is limited to the preparation of proteins exhibiting this particular molecular weight.
This aspect of the invention arises out of the inventors successful cloning of DNA encoding the 60 kD Ro antigen. From knowledge of this 60 kD Ro antigen DNA sequence as disclosed herein, one is enabled to prepare DNA sequences which encode a peptide which include at least an epitopic core sequence of the 60 kD Ro antigen, or which encode the full length antigen itself. Moreover, from knowledge of the biological interchangeability of various amino acids which allow one to alter amino acid structures without altering their underlying their biological functional activity, one is enabled by the present disclosure to prepare a wide range of equivalent embodiments, so called biologically functional equivalents as discussed below.
The invention is thus concerned in particular aspects with DNA sequences which encode the 60 kD Ro antigen identified as having an amino acid sequence essentially as set forth in FIG.
2
Capra J. Donald
Lieu Tsu-San
McCauliffe Daniel P.
Sontheimer Richard D.
Board of Regents , The University of Texas System
Fulbright & Jaworski LLP
Kunz Gary L.
Landsman Robert S.
LandOfFree
DNA segments encoding autoimmune polypeptide epitopes of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with DNA segments encoding autoimmune polypeptide epitopes of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and DNA segments encoding autoimmune polypeptide epitopes of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2612543