Protein which is characteristic of rheumatoid arthritis

Claim 1

A rheumatoid arthritis factor isolated from the sera of human rheumatoid arthritis patients and identifiable by the following characteristics: (a) isoelectric pH range of 5.1 to 5.3 (b) precipitated from human serum in 0.02 molar acetate buffer at pH 5.51 (c) soluble in 0.026 molar ethylene glycol tetraacetic acid (EGTA) at pH 7.5 (d) present in euglobulin fraction of human sera (e) molecular weight of about 135,000 as detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis (f) enlarges the size of the Clq precipitin ring in radial immunodiffusion (g) inhibits the hemolytic activity of Clq (h) inhibits the binding of Clq to fibronectin (i) over 90% by weight of the total molecular weight is accounted for by the following amino acids: ______________________________________ Aspartic acid Alanine Threonine Valine Serine Phenylalanine Glutamic acid Histidine Proline Glycine Isoleucine Cysteine Leucine Tyrosine Lysine Arginine ______________________________________ (j) nonreactive with antibodies in human IgG, IgA or IgM.

Claim 11

A method of detecting rheumatoid arthritis in a human which comprises incubating the serum from an individual under test with a composition containing a diagnostically effective amount of the F(ab') 2 fraction, the Fab fraction or a mixture of such fractions of an antibody to a fheumatoid arthritis factor, said factor, isolated from the sera of human rheumatoid arthritis patients and identifiable by the following characteristics: (a) isoelectric pH range of 5.1 to 5.3 (b) precipitated from human serum in 0.02 molar acetate buffer at pH 5.5 (c) soluble in 0.026 molar ethylene glycol tetraacetic acid (EGTA) at pH 7.5 (d) present in euglobulin fraction of human sera (e) molecular weight of about 135,000 as detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis (f) enlarges the size of the Clq precipitin ring in radial immunodiffusion (g) inhibits the hemolytic activity of Clq (h) inhibits the binding of Clq to fibronectin (i) over 90% by weight of the total molecular weight is accounted for by the following amino acids: ______________________________________ Aspartic acid Alanine Threonine Valine Serine Phenylalanine Glutamic acid Histidine Proline Glycine Isoleucine Cysteine Leucine Tyrosine Lysine Arginine ______________________________________ (j) nonreactive with antibodies to human IgG, IgA or IgM.

Claim 12

A method of detecting rheumatoid arthritis in a human which comprises incubating the serum from an individual under test with a composition containing a diagnostically effective amount of the F(ab') 2 fraction, the Fab fraction or a mixture of such fractions of an antibody to a fheumatoid arthritis factor, said factor, isolated from the sera of human rheumatoid arthritis patients and identifiable by the following characteristics: (a) isoelectric pH range of 5.1 to 5.3 (b) precipitated from human serum in 0.02 molar acetate buffer at pH 5.5 (c) soluble in 0.026 molar ethylene glycol tetraacetic acid (EGTA) at pH 7.5 (d) present in euglobulin fraction of human sera (e) molecular weight of about 135,000 as detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis (f) enlarges the size of the Clq precipitin ring in radial immunodiffusion (g) inhibits the hemolytic activity of Clq (h) inhibits the binding of Clq to fibronectin (i) over 90% by weight of the total molecular weight is accounted for by the following amino acids: ______________________________________ Aspartic acid Alanine Threonine Valine Serine Phenylalanine Glutamic acid Histidine Proline Glycine Isoleucine Cysteine Leucine Tyrosine Lysine Arginine ______________________________________ (j) nonreactive with antibodies to human IgG, IgA or IgM.