Department of Preventive Medicine, Washington University School of Medicine, St. Louis, Mo.
Department of Medicine, Washington University School of Medicine, St. Louis, Mo.†
Address requests for reprints to Dr. Eng M. Tan, Dept. of Preventive Medicine, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, Mo. 63110.*
Submitted for publication August 4, 1966; accepted January 12, 1967.
Supported by a grant from the John A. Hartford Foundation to the Laboratory for the Study of Arthritis and Rheumatic Diseases, Barnes Hospital, St. Louis, Mo., and in part by U. S. Public Health Service grant AM 10495.
Presented in part at the Annual Meeting of the American Rheumatism Association, Denver, Colo., June 18, 1966.
First published May 1, 1967 - More info
Double diffusion in agarose was employed for the characterization of a soluble nucleoprotein antigen that gave precipitin reactions with sera from patients with systemic lupus erythematosus. The soluble antigen that was isolated from calf thymus nuclei was demonstrated by enzyme degradation and ultracentrifugation studies, and by immunologic analysis, to be a complex of deoxyribonucleic acid and a moiety susceptible to proteolytic digestion. Antibody to soluble nucleoprotein did not react with the DNA portion of the complex released after proteolytic digestion or with purified calf thymus DNA. Immunologic reaction of identity was obtained between the soluble nucleoprotein antigen and synthesized DNA-histone complex, suggesting that the protein moiety of soluble nucleoprotein might in part be composed of histone. Antibody to soluble nucleoprotein was present in 51% of systemic lupus erythematosus sera examined and was more common than antibody to deoxyribonucleic acid.